Ivanov V., Geva O.N., Gaverova Yu.G. Workshop on organic chemistry
the liquid becomes cloudy due to the formation of a white precipitate of tribromophenol.
An experience VI . sulfonation of phenol.
Several phenol crystals are placed in a test tube and 3 drops of sulfuric acid are added. Shake the contents of the tube: the phenol crystals dissolve. A drop of the resulting solution is added to another test tube and 4-5 drops of water are added: phenol is released in the form of turbidity.
The reaction mixture in the first tube is heated in a boiling water bath for 2-3 minutes, then the contents of the tube are cooled and poured into a test tube with 10 drops of cold water. A homogeneous solution is formed, almost without the characteristic smell of phenol.
An experience VII . nitration of phenol.
A few crystals of phenol, 2-3 drops of water are placed in a test tube and shaken until a homogeneous solution is formed. Place 3 drops in another test tube nitric acid conc. and 3 drops of water. Dilute nitric acid is added dropwise to liquid phenol, all the while vigorously shaking and cooling the reaction tube - the reaction is very vigorous. The reaction mixture is poured into a test tube with a few drops of water. The opening of the tube is closed with a stopper with a gas outlet tube and o-nitrophenol is distilled off into a clean, dry receiver tube. The cloudy liquid drop in the receiver has a characteristic bitter-almond smell of o-nitrophenol. The para-isomer remains in the reaction tube.
SELF-CHECK QUESTIONS
How does temperature affect the solubility of phenol in water?
Why does phenol turn pink, redden in air and blur when standing?
Why are acidic properties more pronounced in phenol than in alcohols of the limiting series?
Why is it called "carbolic acid"?
Why does carbonic acid displace phenol from phenolate?
What compounds are obtained by brominating phenol?
What reactions can be used to distinguish a solution of phenol from solutions of alcohols of the limiting series?
Lab #10
aldehydes and ketones. properties
Objective: 1. Carry out a color reaction for formaldehyde and acetaldehyde with fuchsine sulfuric acid.
2. Study qualitative reactions to aldehydes.
3. Study the qualitative reaction to acetone.
Reagents: formaldehyde, acetic aldehyde, fuchsine sulfuric acid, ammonia solution of silver oxide, caustic soda 2n., copper sulphate, acetone, iodine solution in potassium iodide.
equipment
An experience I . Color reaction for aldehydes with fuchsine sulfuric acid.
2 drops of fuchsine sulfuric acid solution are placed in two test tubes and 2 drops of formaldehyde solution are added to one of them, 2 drops of acetaldehyde are added to the other. What are you watching?
An experience II . oxidation of aldehydes with a solution of silver oxide. (Silver mirror reaction)
In a clean test tube, 2 drops of an ammonia solution of silver oxide are introduced. Then 1 drop of formaldehyde solution is added and heated over the flame of an alcohol lamp. A plaque of a silver mirror appears on the walls of the test tube.
An experience III . oxidation of aldehydes with copper hydroxide.
Place 4 drops of sodium hydroxide solution in a test tube, dilute it with 4 drops of water and add 2 drops of copper sulphate solution. To the precipitation of copper hydroxide, add 1 drop of formaldehyde solution and heat to a boil. A yellow precipitate of copper hydroxide is separated, turning into red copper oxide.
An experience IV . obtaining iodoform from acetone.
Place in a test tube 3 drops of a solution of iodine in potassium iodide and 5 drops of a solution of caustic soda. The solution becomes colorless. Add 1 drop of acetone to the decolorized solution. Immediately without heating, a yellowish-white precipitate with a characteristic smell of iodoform falls out.
SELF-CHECK QUESTIONS
Why are the boiling points of the lower members of the aldehyde and ketone series higher than those of the corresponding carbohydrates and lower than those of the corresponding alcohols?
What determines the activity of carbonyl compounds?
How do electron-withdrawing or electron-donating substituents affect the electron density of carbonyl carbon?
Why are aldehydes more active than ketones?
How can you determine the structure of a ketone?
How can the following substances be distinguished: formic aldehyde, acetaldehyde, acetone?
Which aldehydes do not undergo aldehyde condensation?
Industrial methods for producing acetone, its application?
Industrial methods for producing acetaldehyde?
Lab #11
properties of monobasic carboxylic acids
Objective: 1. Examine the physical properties.
2. Substantiate the acidic properties of carboxylic acids.
3. Substantiate the distinctive properties of formic acid.
Reagents: acids: formic, acetic, oxalic, stearic, distilled water, acetic acid 0.1n solution, magnesium powder, sodium carbonate, barite water, methyl orange solution, litmus blue, phenolphthalein, sodium formic acid, sulfuric acid 2n solution, potassium permanganate 0.1N solution, conc. sulfuric acid, sodium acetate cr., iron chloride 0.1N.
equipment: test tubes, vent tube, spirit lamps, matches, holder, spoon.
An experience I . solubility in water of various acids.
Three drops or several crystals of each of the studied acids are shaken in a test tube with 5 drops of water. If the acid does not dissolve, heat the tube. Hot solutions are cooled and the separation of acid crystals is noted, which dissolve only when heated.
Lab #9
study of the properties of phenols
Objective: 1. To study the physical properties of phenols.
2. Substantiate acidic properties.
3. Perform qualitative reactions for phenols.
Reagents: phenol crystal, sodium hydroxide 2n solution, hydrochloric acid 2n solution, iron chloride 1.0n solution, bromine water, sulfuric acid conc., nitric acid conc.
equipment: test tubes, spirit lamps, holder, matches, water bath.
An experience I . dissolving phenol in water.
Place 2 drops of liquid phenol in a test tube, add 2 drops of water and shake. A cloudy liquid is formed - an emulsion of phenol. Allow the contents of the tube to settle. After peeling, the emulsion gradually separates: the top layer is a solution of phenol in water, the bottom layer is a solution of water in phenol. Phenol is poorly soluble in cold water. Gently heat the contents of the tube. A homogeneous solution is obtained. On cooling, a cloudy liquid forms.
An experience II . obtaining sodium phenolate.
Place 4 drops of an emulsion of phenol in water into a test tube and add 2 drops of sodium hydroxide solution. A clear solution of sodium phenolate is formed immediately, as dissolves well in water. The solution is left for the next experiment.
An experience III . decomposition of sodium phenolate with hydrochloric acid.
To half of the clear sodium phenolate solution (from the previous experiment) add a drop of hydrochloric acid. Again free phenol in the form of an emulsion.
An experience IV . the reaction of phenol with ferric chloride (III).
Place 2 drops of phenol solution in a test tube, add 3 drops of water and 1 drop of ferric chloride solution. An intense red-purple color appears.
An experience V . obtaining tribromophenol.
2 drops of bromine water are introduced into the test tube and a drop of an aqueous solution of phenol is added. In this case, bromine water becomes colorless and
An experience V . oxidation of ethyl alcohol with copper oxide (II).
Place 2 drops of ethyl alcohol into a dry test tube. Holding a spiral of copper wire, heat it in a burner flame until a black coating of copper oxide appears. Another hot spiral is lowered into a test tube with ethyl alcohol. The black surface of the spiral becomes golden due to the reduction of copper oxide. At the same time, a characteristic smell of acetic aldehyde (the smell of apples) is felt.
An experience VI . Oxidation of ethyl alcohol with potassium permanganate.
Place 2 drops of ethyl alcohol, 2 drops of potassium permanganate solution and 3 drops of sulfuric acid solution into a dry test tube. Carefully heat the contents of the test tube over a burner flame. The pink solution is discolored. There is a characteristic smell of acetaldehyde.
An experience VII . The interaction of glycerol with copper hydroxide (II).
Place 2 drops of copper sulfate solution, 2 drops of sodium hydroxide solution in a test tube and mix - a blue gelatinous precipitate of copper (II) hydroxide is formed. Add 1 drop of glycerin to the test tube and shake the contents. The precipitate dissolves and a dark blue color appears due to the formation of honey glycerin.
SELF-CHECK QUESTIONS
Why do alcohols dissolve well in water?
Why do primary alcohols boil at a higher temperature than secondary ones, and secondary ones at a higher temperature than tertiary ones?
What causes the acidic properties of alcohols?
How can one explain that acidic properties are more pronounced in propyl alcohol than in isopropyl alcohol, and in ethylene glycol more pronounced than in ethyl alcohol?
What reactions can be used to distinguish ethyl alcohol solutions from ethylene glycol solutions?
How is the association of alcohols carried out?
What products are obtained from the oxidation of primary alcohols, secondary alcohols?
An experience II . acidic properties of carboxylic acids.
Place 1 drop of acetic acid solution into three test tubes. Add 1 drop of methyl orange to the first tube, 1 drop of litmus to the second, and 1 drop of phenolphthalein to the third. A red color appears in a test tube with methyl orange, and a pink color appears in a test tube with litmus. Phenolphthalein remains colorless.
Place 2 drops of acetic acid solution in a test tube and add a little magnesium. A hot splinter is brought to the opening of the test tube. In this case, a flash is observed, accompanied by a sharp sound, characteristic of a flash of a mixture of hydrogen and air.
An experience III . formation and hydrolysis of iron acetate.
A few crystals of sodium acetic acid, 3 drops of water and 2 drops of iron (III) chloride solution are placed in a test tube. The solution turns yellowish-red as a result of the formation of the iron salt of acetic acid. The solution is heated to boiling. Flakes of the main salts of a red-brown color immediately fall out.
An experience IV . oxidation of formic acid with potassium permanganate.
Pour 2 ml of formic acid solution into a test tube, add 2 drops of potassium permanganate solution and 3 drops of sulfuric acid solution. The opening of the test tube is closed with a stopper with a gas outlet tube, the end of which is lowered into a test tube with barite water. The contents of the test tube are heated in the flame of a burner. After a few seconds, the pink solution becomes colorless and the barite water in the second test tube becomes cloudy.
An experience V . decomposition of formic acid when heated with conc. sulfuric acid.
3 drops of formic acid, 3 drops of concentrated sulfuric acid are poured into a test tube and the mixture is heated in a burner flame. Gas is released violently. When ignited, the gas burns with bluish flashes.
SELF-CHECK QUESTIONS
Which acids do not dissolve in water?
Why do acids boil at a higher temperature than ROH?
What explains the acidic properties of carboxylic acids?
Which acid is stronger: formic or acetic and why?
Where are acid properties more pronounced in acids or alcohols, and why?
How is formic acid different from acetic acid?
What reagents can distinguish formic acid from other acids?
Why is there no bond breaking in the carbonyl group in carboxylic acids, unlike aldehydes and ketones?
How do donor and acceptor groups affect the acidic properties of acids?
Lab #12
properties of dibasic carboxylic acids
Objective: 1. Study the properties of dibasic carboxylic acids using oxalic acid as an example.
2. Substantiate its distinctive properties.
Reagents: sodium formic acid crystal, calcium chloride 0.1N solution, oxalic acid crystal, sulfuric acid conc., barite water sat. solution, potassium permanganate 0.1n solution, sulfuric acid 0.2n.
equipment: test tubes, vent tube, spirit lamp, matches, holder.
An experience I . obtaining sodium salt of oxalic acid.
A few grains of formic acid sodium are placed in a dry test tube and strongly heated on a burner flame. Molten salt decomposes with the release of hydrogen. The contents of the test tube are allowed to cool, 3-4 drops of water are added to the alloy and slightly heated until a clear solution appears.
Place a few grains of sodium formic acid into another test tube and add 3-4 drops of water. Add 1 drop of calcium chloride solution to both tubes. In the first tube (with sodium oxalate), a white precipitate of water-insoluble calcium salt of oxalic acid is formed. In a test tube with a solution
Lab #8
study of the properties of monatomic and
polyhydric alcohols
Objective: 1. To study the physical properties of alcohols.
2. Substantiate the acidic properties of alcohols and their relationship to indicators.
3. Substantiate the oxidizability of alcohols.
4. Carry out a qualitative reaction for polyhydric alcohols.
Reagents: ethyl alcohol, glycerin, anhydrous CuSO 4 , litmus paper, 1% phenol-phthalein solution, sodium (met.), copper wire spiral, KMnO 4 0.1n, 2n H 2 SO 4 solution, CuSO 4 0 , 2n, NaOH solution 2n, filter paper, H 2 O dist.
equipment: test tubes, spirit lamp, tweezers, holder, matches.
An experience I . detecting the presence of water in alcohol.
A little powder of anhydrous copper sulfate is placed in a dry test tube and 3-4 drops of ethyl alcohol are added. The mixture is shaken well and heated gently. The white powder quickly turns blue.
An experience II . solubility of ethyl alcohol in water.
Place 2 drops of ethyl alcohol in a dry test tube and add water drop by drop. Turbidity is not observed. Ethyl alcohol is miscible with water in every way.
An experience III . ratio of alcohols to indicators.
3 drops of water are placed in four test tubes and 2 drops of ethyl, propyl, butyl and isoamyl alcohols are added. Alcohol solutions are tested for phenolphthalein and litmus.
An experience IV . Formation and hydrolysis of alcoholates.
Place in a dry test tube small piece metallic sodium. Add 3 drops of ethyl alcohol and close the tube with your finger. At the end of the reaction, bring the test tube to the flame of the burner and remove the finger. The escaping hydrogen ignites at the opening of the test tube. The whitish precipitate of sodium ethoxide remaining at the bottom of the test tube is dissolved in 2-3 drops of distilled water, 1 drop of an alcohol solution of phenolphthalein is added - a crimson color appears.
until the disappearance of potassium bromide crystals in the reaction tube.
Two layers are formed in the receiver: the lower one is ethyl bromide, the upper one is water. Remove the top layer with a pipette. With a glass rod, a drop of ethyl bromide is introduced into the flame of the burner. The flame is painted around the edges in green. What reactions take place?
An experience II . obtaining ethyl chloride.
Small crystals of sodium chloride are poured into a test tube (layer 1 mm high), then 3 ml of ethyl alcohol, 3 ml of conc. sulfuric acid are added, the mixture is heated on the flame of an alcohol lamp. The liberated ethyl chloride ignites, forming a characteristic green ring.
Write a reaction equation, characterize ethyl chloride.
An experience III . obtaining iodoform from ethyl alcohol.
1 ml of ethyl alcohol, 3 ml of a solution of iodine in potassium iodide and 3 ml of 2N sodium hydroxide are placed in a test tube.
The contents of the test tube are heated without boiling, because in a boiling solution, iodoforms are cleaved with alkali. A whitish turbidity appears, from which iodoform crystals gradually form upon cooling. If the turbidity dissolves, then add another 3-4 drops of iodine solution to the warm reaction mixture and thoroughly mix the contents of the test tube until crystals begin to separate. 2 drops of sediment are transferred to a glass slide and viewed under a microscope.
What is the shape of iodoform crystals?
Write an equation for the corresponding reactions. Describe iodoform.
SELF-CHECK QUESTIONS
What determines the boiling point and density of halogen derivatives?
Why halogenated reactive substances?
What determines the reactivity of halogen derivatives?
Why does the halogen in aryl halides deactivate the core?
sodium formic acid precipitate is not obtained, tk. the calcium salt of formic acid is soluble in water.
An experience II . decomposition of oxalic acid when heated with conc. sulfuric acid.
Place several crystals of oxalic acid in a test tube and add 2 drops of sulfuric acid. The test tube is closed with a stopper with a gas outlet tube and heated on a heating pad flame. The escaping gas is ignited - it burns with bluish flashes. After that, the end of the gas outlet tube is lowered into barite water. Barite water becomes cloudy.
An experience III . oxidation of oxalic acid with potassium permanganate.
A few crystals of oxalic acid are placed in a test tube, 2 drops of potassium permanganate and 1 drop of sulfuric acid are added. The opening of the test tube is closed with a stopper with a gas outlet tube, the end of which is lowered into a test tube with barite water. The reaction mixture is heated. The pink solution of potassium permanganate becomes discolored, and a white precipitate of carbonate appears in a test tube with barite water.
An experience IV . decomposition of oxalic acid when heated.
Several crystals of oxalic acid are heated in a test tube with a vent tube, the extended end of which is lowered into a test tube with barite water. The gas released when heated causes the barite water to become cloudy. After that, the gas outlet tube is removed from the test tube with barite water and the gas is ignited.
SELF-CHECK QUESTIONS
How do 2-basic acids differ in structure from monobasic acids?
How is oxalic acid different from other 2 basic acids?
Where are the acid properties more pronounced in oxalic acid or acetic acid?
What properties does oxalic acid exhibit when interacting with potassium permanganate?
How is oxalic acid produced industrially?
Where is oxalic acid used?
Lab #13
higher carboxylic acids. soap
Objective: 1. To study the properties of higher carboxylic acids, to substantiate their acidic nature.
2. Separate higher acids from soaps.
3. Prove the unsaturation of higher acids.
Reagents: stearin, diethyl ether, sodium hydroxide solution 0.1n, phenolphthalein, solid soap, distilled water, conc. solution, sulfuric acid 2n, bromine water, ethyl alcohol, calcium chloride 0.1n.
equipment: test tubes, spirit lamps, matches, spoons.
An experience I . acidic properties of stearin.
Place 4 drops of diethyl ether into two dry tubes. A small piece of stearin is added to one test tube and dissolved in ether without heating. In both tubes add 1 drop of phenolphthalein, 1 drop of sodium hydroxide solution and shake thoroughly. In a test tube containing stearin, a crimson color appears, which disappears with stirring. In a test tube with ether and alkali, a persistent crimson color appears.
An experience II . dissolving soap in water.
A piece of soap (about 10 mg) is placed in a test tube, 5 drops of water are added, and the contents of the test tube are thoroughly shaken for 1-2 minutes. after that, the contents of the test tube are heated in the flame of a burner. Sodium and other alkaline soaps (potassium, ammonium) dissolve well in water.
An experience III . extraction of higher acids from soap.
Place 5 drops of conc. soap solution, add 1 drop of sulfuric acid solution and slightly heat the contents of the test tube in a burner flame. A white oily layer of free floats fatty acids. The aqueous solution is clarified. Leave the contents of the tube for the next experiment.
An experience IV . proof of the unsaturation of the fatty acids that make up the soap.
Add 3 drops of bromine water to a test tube with isolated fatty acids and shake vigorously - bromine water becomes colorless. Consequently, the composition of fatty acids isolated from soap also includes unsaturated acids, which are easily attached
SELF-CHECK QUESTIONS
What do the boiling and melting points of arenes depend on?
Why does benzene exhibit electrophilic grounding reactions?
Why is benzene resistant to the action of an oxidizing agent?
How do addition reactions proceed in arenas and why?
How do substitution and oxidation reactions proceed in arenes and why?
Why does the nitration of benzene take place in the presence of sulfuric acid?
Substituents of the first kind, their guiding action?
Substituents of the second kind, their guiding action?
Arrange the suggested substances in order of increasing activity.
SO 3 H NO 2 CH 3 NH 2
A B C D E)
Lab #7
halogen derivatives
Objective: 1. Learn how to get halogen derivatives in the laboratory.
2. Study the properties of halogen derivatives
Reagents: ethyl alcohol, concentrated sulfuric acid, potassium bromide crystal, sodium chloride crystal, iodine solution in potassium iodide, caustic soda 2n.
equipment: test tubes, spirit lamp, vent tube, matches, holder, microscope, glass slide.
An experience I . production of ethyl bromide.
3 ml of alcohol, 2 ml of water, 3 ml of concentrated sulfuric acid are placed in a test tube with a gas outlet tube. After cooling the heated alcohol-acid mixture, several crystals of potassium bromide are placed in it. The tube is fixed obliquely in the leg of the tripod and the contents of the tube are carefully heated to a boil. The end of the gas outlet tube is immersed in another test tube containing 6-7 drops of water and cooled with ice. Heating leads to bromine at the site of double bond rupture, while discoloring bromine water.
equipment: test tubes, porcelain cup, glass, burette, matches.
An experience I . solubility of benzene in various solvents.
Place one drop of benzene into three test tubes. Add 3 drops of water to one test tube, 3 drops of alcohol to another, 3 drops of ether to the third test tube. Shake the contents of the tube thoroughly. In a test tube with alcohol and ether, a homogeneous solution is formed, in a test tube with water there are 2 layers.
Conclusion: benzene is practically insoluble in water, it dissolves well in organic solvents.
An experience II . burning benzene.
The experiment is carried out in a fume hood. 1 drop of benzene is placed in a porcelain cup and set on fire. Benzene burns with a bright, smoky flame.
An experience III . Oxidation of benzene and its homologues.
1. Oxidation of benzene.
3 drops of water, 1 drop of potassium permanganate solution and 1 drop of sulfuric acid solution are placed in a test tube.
2 drops of benzene are added to the resulting solution and the contents of the test tube are shaken; the pink solution does not discolor. One of important conditions is its resistance to oxidizing agents.
2. oxidation of toluene.
3 drops of water, 1 drop of potassium permanganate solution and 1 drop of sulfuric acid solution are placed in a test tube. Then add 1 drop of toluene and shake vigorously for 1-2 minutes.
What's happening? Write the reaction equation.
An experience IV . Nitration of benzene.
In a test tube with chilled water, place 2 ml of conc. sulfuric acid and 1 ml conc. nitric acid. Shake the liquid continuously, add 1 ml of benzene drop by drop. When the benzene solution has been added, transfer the test tube to a beaker of hot water and shake it vigorously until all the benzene has dissolved. After that, pour the liquid into a glass with a small amount of water and let it stand. Note the smell of almonds.
An experience V . hydrolysis of an alcoholic solution of soap.
Place a bar of soap, 4 drops of alcohol into a dry test tube, shake vigorously and add 1 drop of phenolphthalein. The color of the solution does not change. Dist. is added dropwise to an alcoholic solution of soap. water. As water is added, a pink color appears. The color intensity increases.
An experience VI . formation of insoluble calcium salts of fatty acids.
Place 2 drops of soap solution, 1 drop of calcium chloride solution into a test tube and shake the contents of the test tube. A white precipitate falls out.
SELF-CHECK QUESTIONS
How are higher carboxylic acids obtained in industry?
How are soaps made in industry?
Why do soaps coagulate in hard water?
Justify the strength of higher carboxylic acids.
How to prove the presence of a double bond in unsaturated higher carboxylic acids?
What are the disadvantages of soaps and what are they replaced with?
Explain why fabrics become stiff when washed with soaps?
Lab #14
nitro compounds. sulfo compounds
Objective: 1. Obtain nitrobenzene and study its properties.
2. Get nitrotoluene and study its properties.
3. Get benzenesulfonic acid and study its properties.
Reagents: benzene, nitric acid conc., sulfuric acid conc., toluene.
equipment: water bath, thermometer, tile.
An experience I . obtaining nitrobenzene.
Place 2 drops of concentrated nitric acid and 3 drops of concentrated sulfuric acid into a dry test tube.
The resulting nitrating mixture is cooled and 2 drops of benzene are added. The test tube is placed in a water bath, heated to 50-55°C for 2-3 minutes, constantly shaking the test tubes, then the reactive mixture is poured into a pre-prepared test tube with water. A drop of heavy, slightly yellowish nitrobenzene, cloudy from the presence of moisture, falls to the bottom. Set aside until the next experiment.
An experience II . obtaining dinitrobenzene.
2 drops of nitric acid, 3 drops of sulfuric acid are placed in a test tube. 2 drops of nitrobenzene are added to the hot nitrating mixture and heated in a boiling water bath with constant shaking for 3-4 minutes.
Then the reactive mixture is cooled and poured into a test tube with water. Dinitrobenzene is initially released in the form of a heavy oily droplet, then quickly turns into a crystalline state.
An experience III . nitration of toluene.
In a test tube, a nitrating mixture is prepared from 2 drops of concentrated nitric acid and 3 drops of concentrated sulfuric acid. Add 2 drops of toluene to the nitrating mixture and shake vigorously the contents of the tube. After 1-2 min. the reaction mixture is poured into a test tube with water. A heavy drop of nitrotoluene sinks to the bottom.
An experience IV . obtaining benzenesulfonic acid.
3 drops of benzene and 5 drops of concentrated sulfuric acid are placed in a test tube. The contents of the tube are heated in a boiling water bath with constant shaking of the reaction mixture. After obtaining a homogeneous solution, pour the sulfomass into a test tube with 10 drops of cold water. If the sulfonation is completed completely, a clear solution is formed, since sulfonic acids are soluble in water.
SELF-CHECK QUESTIONS
Why is nitrobenzene obtained at a temperature of 50°C, and dinitrobenzene at a higher temperature?
How do the O 2 and O 3 H groups affect the activity of the benzene ring?
Which reacts more easily benzene or nitrobenzene, benzene or benzenesulfonic acid?
An experience III . Formation of silver acetylene.
Assemble the device as indicated in the previous experiment. A few drops of ammonia solution of silver oxide are added to the test tube. A current of acetylene is passed through this solution. In the test tube, a light yellow precipitate of silver acetylenide is formed, which then turns gray.
An experience IV . Formation of copper acetylenide.
Place 1-2 pieces of calcium carbide in a dry test tube and add 2 drops of water. A strip of filtered paper moistened with an ammonia solution of copper chloride CuCl is inserted into the opening of the test tube. A red-brown color appears due to the formation of copper acetylenide.
SELF-CHECK QUESTIONS
Why must all parts of the apparatus be dry before starting the reaction?
Is the acetylene reaction exothermic or endothermic?
Why is the ground reaction possible for acetylene, but not for ethylene?
What is the difference between the flame during the combustion of acetylene and the flame of methane. Why?
What reaction equations can be used to distinguish acetylene from methane?
NaNH 2 +CH 3 ×CH 2 Cl +H 2 O × H 2 SO 4
There are transformations:
CH 4 ¾¾®X¾¾¾¾®X 1 ¾¾¾¾®X 2 ¾¾¾¾®X 3
Lab #6
arenes, benzene, toluene, properties
Objective: 1. Examine properties aromatic hydrocarbons:
The ratio of benzene to various solvents.
2. Study the chemical properties:
benzene burning
oxidation of benzene and its homologues
benzene nitration
Reagents: benzene, water, alcohol, ether, 2n sulfuric acid, potassium permanganate, 0.1n toluene solution, conc. sulfuric acid, conc. nitric acid.
3. Why should the sulfuric acid used in the experiment be concentrated?
4. What qualitative reactions can be used to distinguish ethylene from methane?
5. Carry out transformations:
H 2 SO 4 + HCl + KOHsp.r. + KmnO 4
C 2 H 5 OH¾¾¾®X¾¾¾®X 1 ¾¾¾®X 2 ¾¾¾®X 3
Lab #5
obtaining acetylene. study of the properties of alkynes
Objective: 1. Obtain acetylene experimentally.
2. Study its properties and note the similarities and differences between acetylene and previously studied hydrocarbons.
Reagents: calcium carbide, dist. water, ammonia solution of copper (I) chloride, ammonia solution of silver oxide, potassium permanganate, bromine water.
equipment: test tubes, a large test tube with a test tube with a drawn end, cotton wool, matches.
An experience I . acetylene production.
Put a piece of calcium carbide, a small piece of cotton wool into a test tube and moisten with water. Close the wide opening of the test tube with a cork with the end of the tube pulled back, squeeze the released acetylene. At first, acetylene burns with a smoky flame, which at the end of the reaction, when the release of acetylene, becomes completely dazzlingly bright. Write the reaction equation.
An experience II . properties of acetylene.
Assemble the instrument from the test tube with the vent tube. Place a few pieces of calcium carbide in a test tube, lower the long end of the glass tube into a test tube with a dilute solution of potassium permanganate and pass a current of acetylene, for which moisten the calcium carbide with water. After a few minutes, the solution becomes discolored and brown flakes of manganese dioxide hydrate precipitate. Do the same with bromine water.
Observe the discoloration of bromine water.
Lab #15
Amine properties
Objective: 1. Study the physical properties of aniline.
2. Study the chemical properties, justify its basic character.
3. To study qualitative reactions to aniline.
Reagents and equipment: aniline, sulfuric acid 2n, hydrochloric acid conc., sodium hydroxide 2n, phenol-phthalein, litmus red, bleach, newsprint, splinter, bromine water, diphenylamine, nitric acid conc., sulfuric acid conc., microscope, glass slide , test tubes.
An experience I . aniline solubility in water.
Place 5 drops of water and 1 drop of aniline into a test tube and shake vigorously - an emulsion of aniline in water is formed. Add another 3-4 drops of water and shake the contents of the test tube again - the emulsion is preserved.
Aniline is poorly soluble in water. A saturated aqueous solution at 16°C contains 3% aniline.
An experience II . formation of aniline salts and their decomposition.
1. Place 1 drop of aniline and 8 drops of water into a test tube and shake the contents of the test tube. One drop of emulsion is applied to litmus paper.
The color of red litmus does not change.
2. The prepared aniline emulsion is divided into two parts. Sulfuric acid solution is added dropwise to one part. A precipitate of aniline sulphate is formed. Heat the tube until the precipitate dissolves and cool slowly. The precipitated needle-shaped crystals are transferred to a glass slide and examined under a microscope.
An experience III . color reactions of aniline.
1. Color reaction with lingin.
Place 1 drop of aniline, 5 drops of water into a test tube, and add hydrochloric acid drop by drop until a clear solution of aniline hydrochloride is formed. A drop of this solution is applied to a strip of newsprint. A yellow-orange color appears. A splint, dipped into a solution of aniline hydrochloride, also turns yellow-orange. Coloring is due to the presence of lingin in paper and wood.
If a strip of filter paper is moistened with an aniline salt solution, no staining will occur, since the filter paper is pure fiber.
2. color reaction with bleach.
A solution of aniline hydrochloride is prepared and a drop of the solution is applied to a glass slide. Add a drop of bleach solution. A dark green color appears, turning into blue, and then black.
These reactions are based on the easy oxidizability of aniline. The final product is "black aniline" - a dye for cotton fabrics, fur.
An experience IV . aniline bromination.
Place 3 drops of bromine water and 1 drop of aniline water into a test tube. A white precipitate of tribromaniline precipitates.
An experience V . color reaction of diphenylamine with nitric acid.
2-3 crystals of diphenylamine and a drop of sulfuric acid are placed in a test tube, the crystals are stirred until dissolved, i.e. to the formation of the sulfate salt of diphenylamine. One drop of a dilute solution of nitric acid is placed in a test tube with diphenylamine sulfate. A bright blue color appears.
SELF-CHECK QUESTIONS
What are the main properties of amines?
How do donor and acceptor groups affect the basic properties?
Where the main properties are more clearly expressed in
ammonia or methylamine
aniline or ammonia
aniline or methylamine,
methylamine or dimethylamine.
How can aniline be obtained in the laboratory, in industry?
What reagent can be used to distinguish primary amines from secondary, tertiary ones?
Write a reaction equation that allows you to distinguish between aniline, phenol, diphenylamine.
What is the essence of aniline dyeing?
4. Carry out transformations:
С®CH 4 ®C 3 H 8 ®CH 3 ¾CH¾CH¾CH 3 +Cl 2 ®X
Lab #4
obtaining ethylene. study of the properties of alkenes
Objective: Master the laboratory method of obtaining ethylene, study its properties and compare them with the properties of methane.
Reagents: Ethyl alcohol, sulfuric acid (conc.), sand, potassium permanganate, bromine water, ammoniacal copper chloride solution, ammoniacal silver nitrate solution, distilled water, calcium carbide.
equipment: Test tubes, tripod, alcohol lamp, matches, test tube with a stopper with a drawn end, cotton wool, holder.
An experience I . ethylene production and combustion.
A few grains of sand, 2 drops of ethyl alcohol and 4 drops of concentrated sulfuric acid are placed in a dry test tube. Close the test tube with a cork with a gas outlet tube and carefully heat it with the flame of an alcohol lamp. Gas is released, set on fire at the end of the gas outlet tube.
An experience II . addition of ethylene with bromine.
Without stopping the heating of the test tube, lower the end of the gas outlet tube into the test tube with 5 drops of bromine water.
Bromine water becomes colorless.
Experience III. the ratio of ethylene to oxidizing agents.
Without stopping the heating of the test tube, lower the end of the gas outlet tube into a test tube with 2 drops of potassium permanganate solution and 4 drops of water. The solution quickly decolorizes.
SELF-CHECK QUESTIONS
1. Why are alkenes highly reactive with alkanes?
2. What is the difference between an ethylene flame and a methane flame? Why?
placed in a crystallizer with water and bring the end of the tube under a test tube filled with water. The mixture continues to heat up.
When the test tube is filled with methane, take it out of the water and close it with your finger, hold it upside down. Remove the vent tube and stop heating. Light a splinter, and then open the test tube with the hole up, set fire to the methane and carefully pour in the water. Methane burns with a large flame, forms a mixture with air, which, when ignited, gives a strong explosion.
Write the equation for the reactions of production and combustion of methane.
After that, turn the gas outlet tube with the curved end up, attach a small piece of glass tube and pass methane through a solution of potassium permanganate in a test tube and bromine water in another test tube.
Discoloration of the solutions does not occur.
An experience II . oxidation of saturated hydrocarbons
1 drop of the studied alkane (or a mixture of alkanes), 1 drop of sodium carbonate solution and 2-3 drops of potassium permanganate solution are placed in a test tube. The contents of the tube are shaken vigorously. The violet color of the water layer does not change, because Alkanes do not oxidize under these conditions.
An experience III . action of conc. sulfuric acid to saturated hydrocarbons
Place 2 drops of liquid alkane and 2 drops of sulfuric acid into a test tube. The contents of the tube are vigorously stirred for 1-2 minutes, cooling the tube with running water. Under experimental conditions, alkanes do not react with sulfuric acid.
With slight heating, fuming sulfuric acid forms sulfonic acids with alkanes containing a tertiary carbon atom. At high temperatures, sulfuric acid acts as an oxidizing agent.
SELF-CHECK QUESTIONS
1. How the boiling and melting points of alkanes change with the growth and branching of the carbon chain. Why?
2. Explain the strength of the carbon-hydrogen and carbon-carbon bonds in alkanes.
3. Determine the mass fraction of carbon in methane.
Lab #16
carbohydrates. properties of monosaccharides
Objective: 1. Prove the presence of an aldehyde group in glucose.
2. Prove the presence of gr. OH in glucose.
Reagents: glucose 0.5% solution, sodium hydroxide 2n. solution, copper sulfate (II) 0.2n solution, copper saccharate solution, Fehling's reagent, ammonia solution of silver oxide, 0.2n solution of silver nitrate, caustic sodium kots. 40% solution.
An experience I .
Place 1 drop of glucose solution and 5 drops of sodium hydroxide solution into a test tube. To the resulting mixture add 1 drop of copper (II) sulfate solution and shake the contents of the test tube. The bluish precipitate of copper (II) hydroxide Cu (OH) 2 that forms at the beginning dissolves instantly, a transparent solution of copper saccharate is obtained, which has a faint blue color.
An experience II .
5-6 drops of water are added to the alkaline solution of copper saccharate obtained in the previous experiment (the height of the liquid layer should be 10-15 mm). the contents of the test tube are heated over the flame of the burner, holding the test tube at an angle so that only the upper part of the solution is heated, while the lower part remains unheated (for control). When heated gently to boiling point, part of the blue solution turns orange-yellow due to the formation of copper (II) hydroxide CuOH. With longer heating, a red precipitate of copper oxide (I) Cu 2 O may form.
An experience III .
3 drops of glucose solution and a drop of Fehling's reagent (an alkaline solution of copper alkoxide of Rochelle salt) are injected into a test tube. Holding the tube at an angle, gently heat the top of the solution. In this case, the heated part of the solution turns orange-yellow due to the formation of copper (I) hydroxide CuOH, which subsequently turns into a red precipitate of copper (I) oxide Cu 2 O.
An experience IV .
A drop of silver nitrate solution, 2 drops of sodium hydroxide solution are placed in a test tube, and ammonia solution is added dropwise until the precipitate of silver hydroxide is dissolved. Then add 1 drop of glucose solution and slightly warm the contents
tubes over the flame of the burner until the blackening of the solution. Further, the reaction proceeds without heating, and metallic silver is released on the walls of the test tube in the form of a brilliant mirror coating.
An experience V .
Place 4 drops of glucose solution in a test tube and add 2 drops of sodium hydroxide solution. Heat the mixture to a boil and gently boil for 2-3 minutes. The solution turns yellow and then turns dark brown.
When heated with alkalis, monosaccharides, like aldehydes, are resinous and turn brown, while undergoing splitting and partly oxidation.
SELF-CHECK QUESTIONS
laboratory work number 17
starch hydrolysis
Put half a spoonful of starch and prepare 50 ml of starch paste and place it a little in a test tube and cool it. Add a drop of iodine solution here. There was a blue color characteristic of starch. Put 10 ml of starch paste into a test tube, add 1 ml of 10% sulfuric acid solution and boil for 5 minutes.
Let the liquid settle, transfer a few drops to the glass. If a blue color does not appear, this indicates the conversion of starch into a new substance that does not give color with iodine (starch hydrolysis).
To the rest of the liquid, add a few drops of a weak solution of alkali copper sulphate. Bring to a boil.
Divide the solution into two parts, add lead nitrate solution to one part. What color is the precipitate? To the other part, add freshly prepared sodium nitroprusside solution dropwise until a red-violet color appears.
Questions for self-examination
When burning a substance weighing 3.72 g containing carbon, hydrogen, sulfur, 5.26 g of CO 2 were obtained; 3.24 g H 2 O; 3.84 g O 2 . Set the formula of the substance if D n \u003d 15.
When burning 2.28 g of organic matter, 1.92 g of H 2 O was obtained; 7.97 g CO 2 . in addition to carbon and hydrogen, the composition of the substance includes nitrogen, the content of which is 15.04%. What is the formula of the substance?
Lab #3
getting methane. properties study
Objective: 1. Learn how to get methane in the laboratory.
2. Study the properties of alkanes.
Reagents: dehydrated sodium acetate, soda lime, bromine water, potassium permanganate, In solution, sodium carbonate In solution, liquid alkanes, sulfuric acid conc.
equipment: Gas outlet tube with curved end, crystallizer, test tube for collecting gas, beaker, tube with rubber cap, tripod, test tubes, splinter, matches, holder.
An experience I . methane production
To obtain methane, a mixture is prepared consisting of one volume of fused sodium acetate with a double volume of calcined soda lime. The mixture is placed in a porcelain mortar in the volume of one teaspoon and carefully moved and ground into a fine powder. After that, pour into a dry test tube, close the cork with a gas outlet tube and a curved end.
Support the test tube with the mixture horizontally so that the bottom is slightly higher. Gently heat the mixture for 5-10 seconds to release the expanding air. Therefore, release the first portions outward, and then the curved end of the gas outlet tube
Lab #2
Discovery of NITROGEN AND SULFUR in
organic matter
Objective: Determine if the organic matter samples issued contain nitrogen and sulfur.
Reagents: urea crystals, metallic sodium, ethyl alcohol, distilled water, solutions of ferrous sulfate and ferrous chlorite, HCl 2n solution, ammonium thiocyanate cr., lead nitrate, sodium nitroprusside.
equipment: test tubes, spirit lamp, matches, tweezers, knife, filter paper.
An experience I . Discovery of nitrogen in urea.
5-10 mg of urea (several crystals) are placed in a dry test tube and a small piece of metallic sodium is added. Heat the mixture carefully in the flame of a burner until the urea fuses with sodium. At the same time, a small flash is sometimes observed.
After cooling the test tube with the alloy, 3 drops of ethyl alcohol are added to it to eliminate the residues of metallic sodium, which reacts with alcohol not as violently as with water.
Then 5 drops of distilled water are added to the test tube and heated on a burner flame to dissolve the resulting sodium cyanide. After that, 1 drop of a 0.1N solution of ferrous sulfate (FeSO 4), 1 drop of a 0.1N solution of ferric chloride (FeCl 3) and a drop of a 2N solution of hydrochloric acid are added to the test tube for acidification. In the presence of nitrogen, the liquid turns blue color. When conducting the experiment, it is necessary to pay attention to the fact that sodium melts together with organic matter.
An experience II . Discovery of sulfur in ammonium thiocyanate.
Place a few crystals of ammonium thiocyanate and no more than a rusty seed into a dry test tube, a piece of metallic sodium, not contaminated with kerosene. Holding the tube vertically, heat the mixture to red hot so that the sodium melts in the mixture with the substance. Then the test tube with the alloy is cooled and 3 drops of ethyl alcohol are added to it to remove the remaining metallic sodium. After the end of the evolution of gas bubbles (hydrogen), the alloy is dissolved by heating in 5 drops of distilled water.
A red precipitate of cuprous oxide is formed, which indicates the appearance of glucose in solution as a result of starch hydrolysis.
AN EXPERIENCE I . proof of the presence of hydroxyl groups in sucrose.
In a test tube with 1 drop of sucrose solution, 5 drops of alkali solution and 4-5 drops of water are placed. Add 1 drop of copper sulphate solution. The mixture acquires a bluish color due to the formation of copper sucrose. Save the solution until the next experiment.
AN EXPERIENCE II . determination of the reducing ability of sucrose.
The copper saccharate solution is gently heated to boiling over a burner flame, holding the tube so that only the top of the solution is heated. Sucrose does not oxidize under these conditions.
AN EXPERIENCE III . acid hydrolysis of sucrose.
3 drops of 2N hydrochloric acid and 3 drops of water are placed in a test tube with 1 drop of sucrose, carefully heated over the flame of an alcohol lamp for 20-30 minutes, half of the solution is poured into another test tube and 5 drops of alkali and 4 drops of water are added to it. Then 1 drop of copper sulphate solution is added and the top is heated to a boil, an orange-yellow color appears, proving the formation of glucose.
Lab #18-19
study of the properties of polysaccharides.
fiber and its esters
Objective: 1. Examine the physical properties of fiber
dissolution in Schweitzer's reagent.
2. Study the chemical properties of fiber
attitude towards alkalis
relation to acids (formation of amyloid glucose)
3. Obtain an ester of fiber and nitric acid.
Reagents: fiber (cotton wool), Schweitzer's reagent, hydrochloric acid conc., filter paper, sodium hydroxide conc., ammonia 2n, sulfuric acid conc., iodine solution in potassium iodide, sulfuric acid 20%, sodium hydroxide 2n, Fehling's reagent, nitric acid , diethyl ether, water bath, glass slide, porcelain cup, tweezers, thermometer.
An experience I . dissolution of cellulose in Schweitzer's reagent.
A small piece of absorbent cotton is placed in a test tube and 6 drops of Schweitzer's reagent are added. The contents of the test tube are stirred with a glass rod until the cotton wool is completely dissolved. Add 4 drops of water to the resulting viscous solution and mix again. When adding 1-2 drops of concentrated hydrochloric acid, cellulose is released in the form of a white gelatinous precipitate - cellulose hydrate. The released fiber is similar in composition to the original, but does not have a characteristic fibrous structure.
An experience II . interaction of fiber with alkali.
5 drops of water are placed in a test tube and a strip of filter paper is lowered into it so that it reaches the bottom of the test tube. Place 5 drops of sodium hydroxide solution and the same strip of filter paper into another test tube. After 3 min. remove the paper strip from the water and leave to dry. Then the strip is removed from the alkali, washed with water, hydrochloric acid (previously poured into the third test tube), again with water and dried. To speed up drying, strips removed from liquids are lightly squeezed between sheets of filter paper. A strip lying in alkali is denser and shorter than a strip lying in water.
An experience III . obtaining amyloids from cellulose.
Place 3 drops of water and 5 drops of sulfuric acid into a test tube. The resulting hot solution is cooled to room temperature and the end of a strip of filter paper is lowered into it. After 8-10 seconds, the paper is removed, thoroughly washed from acid in running water and in an ammonia solution, and slightly dried. The end of the paper, dipped in acid, becomes more dense and waterproof. One drop of iodine solution is placed at the border of two sections of paper. The area treated with acid turns reddish-blue.
An experience IV . acid hydrolysis of cellulose.
A small piece of filter paper rolled up with a tourniquet is placed in a test tube, 4 drops of conc. sulfuric acid and mix the contents of the test tube with a glass rod. Fiber fibers gradually dissolve. A colorless thick solution is formed. The test tube is placed for several minutes in a boiling water bath, using a pipette, 2 drops of hydrolyzed fiber are placed in a separate test tube, 6 drops of sodium hydroxide solution, a drop of Felink's reagent are added, the contents of the test tube are shaken and
Lab #1
Discovery of carbon, hydrogen, chlorine
in organic matter
Objective: Determine whether the issued samples of organic substances contain carbon, hydrogen, chlorine.
Reagents: copper oxide (II), glucose cr., copper sulphate (anhydrous), Ba (OH) 2, chloroform.
Crockery and equipment: test tubes, cotton wool, vent tube, copper wire, spirit lamp, matches, tripod.
An experience I . Discovery of carbon and hydrogen in glucose.
Pour 5 mm (height) of copper oxide and half a microspade of glucose into a dry test tube, mix thoroughly by shaking the tube. Place a piece of cotton wool in the upper part of the test tube, on which pour a little white CuSO 4 powder. Close the test tube with a gas outlet tube, the end of which is lowered into a test tube with 6 drops of barite water. Heat the appliance over a stovetop or spirit lamp.
An experience II . Discovery of chlorine in chloroform.
The tip of the copper wire, the other end of which is fixed into a stick, is bent into an eye, calcined in the flame of a burner. The wire is covered with a black coating of copper oxide. Make sure that neither copper nor copper oxide stains the flame. Let the wire cool, dip it in chloroform, and put it back into the flame.
What color is the flame?
When calcined, copper oxide oxidizes carbon and hydrogen of organic matter into carbon dioxide and oda, and copper combines with halide. The copper halide formed during the reaction, volatilizing in the flame of the burner, paints it green.
Questions for self-examination
Analysis of a substance consisting of carbon, hydrogen, chlorine gave the following results: (с)=42.6%, (Сl)=50.3%, (Н)=7.1%. Define molecular formula substances, if Dn=70.5.
When burning 4.48 liters of gas, 13.44 liters of CO 2 and 10.8 grams of n 2 were obtained. mass of 1 liter of this gas at n.o. equals 1.875 grams. Determine the true formula of the substance?
First aid kit
assistance in the laboratory:
Boric acid, 2% solution.
Vishnevsky ointment.
Sodium bicarbonate, 1% solution.
Glycerol.
Iodine, 3% alcohol solution.
Adhesive plaster.
A beaker for taking medicines.
Ammonia.
Potassium permanganate, 2% solution.
Rubber tube (harness) 40 cm long.
Glass bath for washing eyes.
sulfidine emulsion.
Acetic acid, 1% solution.
Ethanol.
etherealerion drops.
Before conducting the next lesson in the laboratory, the teacher must repeat the instructions on the precautions that must be observed when using certain reagents in these experiments (concentrated sulfuric and nitric hydrochloric acids, caustic alkalis, etc.)
lightly heated in the flame of a burner. A yellow color appears.
An experience V . obtaining nitrate esters of cellulose.
Place 4 drops of nitric acid and 8 drops of sulfuric acid into a test tube. The hot solution is slightly cooled and a small piece of cotton wool is dipped into it with a glass rod. The test tube is heated in a water bath at a temperature of 70°C, gently stirring the contents. After 3-4 min. the resulting colloxylin is removed with a stick: thoroughly washed with running water, squeezed in filter paper and dried in a porcelain cup in a boiling water bath. The resulting yellowish colloxylin is divided into two parts. A piece of colloxylin cotton wool is brought to the flame of a burner - it instantly flares up. Another piece of colloxylin cotton wool is placed in a dry test tube, 4 drops of the mixture and ether (1:1) are added and mixed. Colloxilin swells and forms a colloidal solution. Pour the solution onto a glass slide. After evaporation of the solvent, the resulting thin film is removed from the glass and introduced into the flame of the burner. It burns out more slowly than cotton wool.
SELF-CHECK QUESTIONS
What compounds are called polysaccharides?
How do polysaccharides differ from oligosaccharides?
What fiber esters are used to obtain varnishes, paints, enamels?
What reactions can be used to distinguish starch from fiber, starch from glucose?
From which you can get more ethyl alcohol from 1 kg of glucose or 1 kg of starch. Justify your answer without using calculations.
What polysaccharides make up starch?
What is the structure of amylose?
What is the difference between amylopectinote and amylose?
What compounds does colloxylin belong to?
Where is colloxylin, pyroxylin, cellulose acetate, viscose used?
How can you get pure fiber?
What substance is obtained during the hydrolysis of cellulose and how can this be proved (write a reaction equation)?
LAB #20
protein properties
Objective: To study the properties of proteins:
color reaction to protein (biuret, xantoprotein, reaction to sulfur, nitrogen-mercury reaction of proteins);
precipitation of proteins;
protein folding.
Reagents: proteins, aqueous solutions, caustic soda 2n. solution, caustic soda conc. solution, nitric acid conc., copper sulfate 0.2n solution, lead nitrate 0.1n solution, white wool, ammonium sulfate sat. solution, hydrochloric acid conc., nitrogen-mercury reagent.
equipment: test tubes, spirit lamp, holder, matches.
An experience I . 1. biuret reaction.
2 drops of the investigated protein solution, 1 drop of alkali solution and 1 drop of copper sulfate solution are placed in a test tube. The liquid turns purple, which is even noticeable in the colored water extract of the meat.
2. Xantoprotein reaction.
3 drops of an aqueous protein solution and 1 drop of nitric acid are introduced into the test tube. A white precipitate appears. When the reaction mixture is heated, the solution and the precipitate turn bright yellow. The mixture is cooled and 1-2 drops of caustic soda are added. In this case, the yellow color turns into a bright orange.
3. REACTION TO SULFUR.
A lump of wool, 2 drops of sodium hydroxide solution, a drop of lead nitrate solution are introduced into the test tube, the contents are heated in the flame of an alcohol lamp. A brown-black precipitate of lead sulfate appears.
4. Nitrogen-mercury reaction of proteins.
Place 2 drops of protein solution and 1 drop of nitrogen-mercury reagent into a test tube, shake the contents of the tube and heat. A characteristic color appears.
An experience II . protein coagulation on heating.
4 drops of the protein solution are poured into a test tube and heated in the flame of an alcohol lamp to a boil. Protein in this case falls out in the form of turbidity or flakes. Cool the contents of the tube slightly, add
VI. SAFETY REQUIREMENTS AFTER WORK COMPLETION
All records of observations should be made immediately after the end of the experiment in the laboratory journal.
After finishing work, wash the used dishes and tidy the workplace.
Report all accidents to the teacher or laboratory assistant immediately.
V. first aid in case of accidents in the laboratory
in case of burns with acids, wash with a 2% solution of baking soda and a solution of KMnO 4;
in case of burns with alkalis, wash with a 1% solution of acetic or citric acid. Apply a bandage from a bandage moistened with alcohol.
When injured with glass, make sure that there is no glass left in the wound, quickly wipe the wound with cotton wool soaked in alcohol, lubricate with iodine and bandage it.
In case of thermal burns, apply a bandage of gauze moistened with a concentrated solution of potassium permanganate to the burnt place, or lubricate this place with burn ointment. If there is no potassium permanganate and ointment, it is recommended to sprinkle with baking soda and apply a bandage moistened cold water.
In case of burns of the face, hands with acid or alkali, wash the affected area with plenty of water, and then:
If acid or alkali gets into the eyes, rinse them with plenty of water, and then:
in case of acid contact, rinse with a dilute solution of baking soda;
in case of contact with alkali - 1% solution boric acid.
If necessary, after rendering first aid, immediately deliver the victim to the first-aid post or polyclinic.
III. WORK SAFETY
IN THE CHEMICAL LABORATORY organic chemistry
The laboratory table must be kept clean and tidy, not cluttered with unnecessary items. Place briefcases and bags on tables.
Dishes should always be washed; do not conduct experiments in contaminated dishes.
Handle glassware with care. Remains broken dishes clean with a dustpan and brush.
All work related to the release of toxic, volatile and unpleasant-smelling substances should be carried out in a fume hood.
Do not perform additional experiments without the permission of teachers.
When determining the smell of substances, keep the opening of the vessel at a distance of 25-30 cm from the face, directing a jet of gas towards you with translational movements of the palm from the opening to the face.
When pouring reagents, do not lean over the vessel to avoid splashes or particles on the face or clothing.
When heating the test tube, do not hold its opening towards yourself or towards your comrades.
Hot objects can only be placed on asbestos cardboard or asbestos mesh.
It is forbidden to store and use flammable liquids (gasoline, alcohol, acetone, etc.) near fire.
In case of ignition of flammable liquids, quickly extinguish the burner, turn off electrical appliances, set aside vessels with flammable substances and extinguish: cover with asbestos or ordinary blanket or cover with sand.
Mercury vapor is hazardous to health. Therefore, if a mercury thermometer is broken or mercury is spilled, it is necessary to report the incident to the teacher and take measures to eliminate it.
It is forbidden to eat in the chemical laboratory and drink water from laboratory glassware.
drop of ammonium sulfate solution and heated until boiling. The amount of coagulated protein in this case increases.
An experience III . precipitation of proteins with concentrated acids.
Pour 2 drops of concentrated nitric acid into the test tube and carefully, tilting the test tube, add 2 drops of protein solution along the wall. After a few seconds, a ring of coagulated protein is formed at the interface between the protein and the acid and increases. The same experiment is repeated with hydrochloric acid. The precipitate formed by the action of hydrochloric acid dissolves when shaken.
An experience IV . precipitation of proteins with salts of heavy metals.
Place 3 drops of protein solution into two test tubes. Add 1 drop of copper sulfate solution to one test tube, 1 drop of lead nitrate solution to another. A flaky precipitate or turbidity is formed. With copper salt - a blue precipitate, with lead salt - white.
An experience V . reversible precipitation of proteins from solutions.
Place 2 drops of protein solution, 2 drops of saturated ammonium sulfate solution into a test tube and lightly shake. A cloud of precipitated protein (globulin) appears. One drop of the cloudy solution is poured into another test tube with 3 drops of water and shaken. The precipitate dissolves.
SELF-CHECK QUESTIONS
What compounds are the main constituents of proteins?
What compounds are obtained by the hydrolysis of proteins?
What is a peptide bond?
How are proteins different from polysaccharides?
What reactions can be used to detect a protein?
How to obtain dipeptides from ethyl alcohol:
glycylglycine
alanilapanim
Lab #21
obtaining polycondensation IUDs
Objective: Get urea-formaldehyde resin and study its properties.
Reagents: crystalline urea, formaldehyde, 40% aqueous solution.
equipment: test tubes, spirit lamp, holder, matches.
An experience I . condensation of urea with formaldehyde.
Place crystalline urea in a dry test tube (layer 2 mm high) and add 2-3 drops of formaldehyde solution until a clear urea solution is obtained. Carefully heat the test tube over a burner flame. After a few seconds, the contents of the tube become cloudy due to the formation of urea-formaldehyde resin.
SELF-CHECK QUESTIONS
What reaction is called a polycondensation reaction?
How is a polycondensation reaction different from a polymerization reaction?
How can urea be obtained, what is the raw material?
How do IUD resins differ from IUD proteins?
Carry out the polycondensation reaction of phenol and formaldehyde.
Suggest a scheme for obtaining urea-formaldehyde resin from CH 3 OH?
Perform transformations:
(NH 4) 2 CO 3 ¾®(NH 2) 2 CO¾¾¾¾®X
II. WHEN USING REAGENTS, IT IS NECESSARY
KNOW THE FOLLOWING RULES:
Solutions and solids for experiments must be taken in such quantity and concentration as indicated in the instructions. If there are no instructions on the dosage of reagents for a given experiment, then they should be taken in the smallest possible amount: 5-7 drops of a solution and one microspatula of a solid.
Keep all bottles with solutions and dry substances closed, open them only during use.
Do not confuse stoppers from bottles, as well as pipettes for taking reagents.
Pour test solutions into test tubes using pipettes only. When using pipettes, make sure that the tip of the pipette does not touch the inner walls of the tube. If the pipette becomes dirty, rinse it with distilled water.
Do not pour out excess reagent and do not pour it back into the vessel from which it was taken, as this can contaminate the contents.
Do not take common use reagents to workplaces; observe the order in the arrangement of both general-purpose reagents and reagents in racks for individual use.
Spilled and spilled reagents must be immediately removed, and the table washed and wiped.
You can not taste the substances. All chemicals are poisonous to some degree.
Pour the remains of silver salts, mercury, as well as concentrated acids and alkalis into special containers located in fume hoods.
Prepare solutions of acids and alkalis in thin-walled dishes; pour the acid into the water in small portions while moving.
When diluting acids, pour them into water, and not vice versa.
Spilled acid or alkali should be covered with sand, and then removed with a shovel and brush. Neutralize the contaminated place with soda if acid is spilled, or a weak solution of acetic acid if alkali is spilled.
It is forbidden to pour solutions of acids and alkalis into the sewer without neutralization.
Before starting laboratory work, students receive (surrender) a work permit. At the end of the semester, students who successfully complete all laboratory work receive a credit. Students who missed classes must work out laboratory work after class under the guidance of a teacher and laboratory assistant and pass a test.
I. SAFETY REQUIREMENTS BEFORE WORKING START
In the laboratory, students must work in white coats.
Work individually, keep quiet.
Check the availability of the necessary equipment and reagents for this work.
Preliminarily repeat the theoretical material of the corresponding chapter and familiarize yourself with the content of the laboratory work.
Understand and strictly observe the order and sequence of operations indicated in the manual.
Observe all precautions indicated in the instructions or verbally communicated by the teacher.
Follow the experiment closely. In case of unsuccessful setting of the experiment and before repeating it, the reason should be established; in doubtful cases, contact the teacher.
All work in the educational chemical laboratory is carried out under the direct supervision of a teacher.
The laboratory should have instructions on how to follow safety rules when performing various types of work.
Each student is assigned permanent place on the desktop, equipped with laboratory supplies.
Students who have been instructed in safety precautions and received admission to classes are allowed to work in the laboratory. An appropriate entry is made in the instruction log, and students sign that they are familiar with the rules.
To ensure fire safety, dry sand, an asbestos blanket, and fire extinguishers must always be available.
To provide the first first aid there should be a first aid kit in the laboratory.
List of reagents required for laboratory work
| 1. Ammonium nitrate 2. Ammonium sulfate 3. Ammonium chloride 4. Ammonia, 25% solution 5. Aluminum (granules) 6. Aluminum sulfate 7. Aluminum chloride 8. Nitrate lead (II) 10. Barium chloride 11. Benzene 13. Glucose 14. Glycerin 15. Metallic iron (shavings, 16. Iron (III) sulfate 17. Iron (III) chloride 18. Yellow blood salt 19. Crystalline iodine 20. Indicators (litmus blue, 21. Phenolphthalein, methyl orange 22. Potassium metal 23. Potassium hydroxide 24. Potassium dichromate 25. Potassium iodide 26. Potassium carbonate 27. Potassium nitrate 28. Potassium sulfide 29. Potassium permanganate 30. Potassium chloride 31. Calcium carbide 32. Potassium chromate 33. Calcium metal 34. Calcium carbonate 35. Calcium chloride 36. Red blood salt | 37. Nitric acid ( \u003d 1.4 g / cm 3) 38. Sulfuric acid ( \u003d 1.84 g / cm 3) 39. Hydrochloric acid ( \u003d 1.19 g / cm 3) 40. Acetic acid (essence) 41. Formic acid 42. Dry starch 43. Vegetable oil 44. Magnesium (shavings) 45. Copper metal (shavings) 46. Copper (II) chloride 47. Copper (II) oxide 48. Copper (II) sulfate 49. Marble, chalk 50. Laundry soap 51. Sodium (metal) 52. Sodium acetate 53. Sodium hydroxide 54. Sodium carbonate 55. Sodium nitrate 56. Sodium chloride 57. Sodium sulfate 58. Sodium sulfite 59. Sodium phosphate 60. Sodium dihydro (hydro) phosphate 61. Sodium silicate 62. Coal (charcoal) 64. Sucrose 66. Silver nitrate 67. Ethyl alcohol 68. Toluene 70. Zinc chloride 71. Magenta 72. Chromium (III) chloride 73. Antimony (III) chloride |
Organization of work and maintaining a laboratory journal. 3
I. Safety requirements before starting work. 4
II. When using reagents, you need to know the following rules. five
III. Safety precautions when working in a chemical laboratory
organic chemistry. 6
IV. Safety requirements at the end of work. 7
V. First aid in case of accidents in the laboratory. 7
First aid kit in the laboratory. 8
Laboratory work №1. Discovery of carbon, hydrogen, chlorine in
organic substances. nine
Laboratory work №2. Discovery of nitrogen and sulfur in organic
substances. 10
Laboratory work №3. Getting methane. Exploring properties. eleven
Laboratory work №4. Getting ethylene. Study of the properties of alkenes. 13
Laboratory work №5. Getting acetylene. Exploring properties
alkynes. fourteen
Laboratory work №6. Arenes, benzene, toluene, properties. 15
Laboratory work №7. Halogen derivatives. 17
Laboratory work №8. The study of the properties of monatomic and
polyhydric alcohols. 19
Laboratory work No. 9. Study of the properties of phenols. 21
Laboratory work №10. Aldehydes and ketones. Properties. 23
Laboratory work №11. Properties of monobasic carboxylic acids. 24
Laboratory work №12. Properties of dibasic carboxylic acids. 26
Laboratory work №13. higher carboxylic acids. Soap. 28
Laboratory work №14. Nitro compounds. Sulfo compounds. 29
Laboratory work №15. properties of amines. 31
Laboratory work №16. Carbohydrates. properties of monosaccharides. 33
Laboratory work №17. hydrolysis of starch. 34
Laboratory work No. 18-19. Study of the properties of polysaccharides.
Cellulose and its esters. 35
Laboratory work №20. Protein properties. 38
Laboratory work №21. Obtaining polycondensation IUDs. 40
List of reagents required for carrying out
laboratory work 41
Introduction
This practical manual for conducting laboratory work in organic chemistry is intended for second-year students of a technical school and is compiled in accordance with the organic chemistry program approved by the Ministry of Education of the Russian Federation for secondary specialized educational institutions.
The program provides for 21 laboratory work, which are carried out by macro and semi-micro methods. The macro method is used in cases where non-toxic reagents are used for work. The introduction of the semi-micro method allows to increase labor productivity, significantly reduce the consumption of reagents, develop skills for accurate, fast and more accurate work, the ability to work without a fume hood.
To work with the semi-micro method, smaller test tubes (4-6 ml), reactive flasks with pipettes, porcelain plates with recesses, Petri dishes are used.
Organization of work and maintaining a laboratory journal
Students prepare for a laboratory lesson using a textbook, notes in abstracts and a practical guide. When performing laboratory work, students according to the results chemical experiments should keep records in a laboratory journal, which has a clear structure and the following sections.
Sample design of the laboratory journal
| What have you been doing | What was observed | Reaction equations | |
When preparing a report, you must follow a certain sequence:
name of the laboratory work, date of completion;
purpose of the work;
number and name of the experiment, a brief description of it, the conditions for conducting it, the design of the device, the number of reagents;
observed changes;
process chemistry;
summarizing conclusions;
answers on questions.
Reviewers: Tambov State University G.R. Derzhavin
Institute of Natural Science Department of Chem. disciplines
PhD chem. Sciences, Professor A. Panasenko
Laboratory workshop in organic chemistry: tutorial for students of technical schools of the second year was developed by T. Tsygankova.
The manual contains laboratory work on organic chemistry, which gives a description of each experience, guidelines for the work, experimental tasks. The textbook is compiled in accordance with the chemistry program recommended by the Ministry of Education of the Russian Federation for secondary specialized educational institutions.
The use of this manual will allow students to more efficiently and effectively use time during laboratory work in organic chemistry.
| Year | Group | Surname |
State educational institution
middle vocational education
"Kotovsky Industrial College"
Laboratory workshop in organic chemistry
(textbook for students
specialties 240505
II college course)
The textbook on the general course of organic chemistry was compiled on the basis of many years of experience of the student workshop on organic chemistry of the Faculty of Chemistry of Moscow State University. M. V. Lomonosov. Contains synthesis techniques organic compounds various classes. The general rules and methods of work in the organic workshop are outlined, general guidelines are given for the interpretation of the 1H and 13C NMR spectra of synthesized compounds. For students, graduate students and teachers of chemical universities, as well as scientists.
First aid for burns, poisoning and other accidents.
For mild thermal burns, wash the affected area with a stream of cold water, rinse with alcohol, and then lubricate with glycerin or boric petroleum jelly. In case of severe burns, wash the affected area with a stream of cold water and call a doctor.
In case of burns with bromine, wash the affected area thoroughly with a stream of cold water, and then with a 10% solution of sodium thiosulfate. After inhaling bromine vapor, you should smell the diluted ammonia solution and go out into fresh air. In case of any damage to the eyes or respiratory tract by bromine, the teacher should be immediately informed and the victim should be sent to a medical institution for qualified assistance.
In case of burns with phenol or its solution, wipe the whitened area of the skin with alcohol until then. until normal skin color is restored, then rinse the affected area with water and apply a compress of cotton wool or gauze moistened with glycerin.
In case of burns with concentrated acid solutions, wash the burned area with a stream of cold water, and then with a 3% soda solution. If acid gets into eyes, rinse with cold running water for 5 minutes and seek medical advice.
In case of burns with concentrated solutions of alkalis, wash the skin with a stream of cold water, and then with a 1% solution of boric acid. Ammonia and amines have almost no effect on the skin, but if they get into the eyes, they can cause severe eye damage. If alkalis and other bases get into the eyes, immediately rinse them with a stream of water, at the same time informing the teacher. Continue washing for several minutes, slightly lifting the eyelid. In case of contact with alkali or bases in the eyes, in any case, you should consult a doctor - even if there are no unpleasant sensations!
In case of accidental ingestion of reagents into the body, immediately drink at least a glass of water and notify the teacher.
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MINISTRY OF HIGHER AND SECONDARY SPECIAL EDUCATION OF THE REPUBLIC OF UZBEKISTAN
TASHKENTINSTITUTETEXTILEANDLIGHT INDUSTRY
department"Chemistry"
UDC547(072).002(076.5)
Teaching aid for laboratory work for bachelors of TITLP direction:
5522300 - Chemical technology of textile, light and paper industries
ORGANICCHEMISTRY
I.I. Gharibyan ,
A.R.Tulaganov
Tashkent- 20 10
Reviewers
Approved at a meeting of the Scientific and Methodological Council of TITLP from " _ 28 _" __May_ _ 2010, protocol no. _ 5 _
Reproduced in the TITLP printing house in the amount of " _ 25 _" copy.
Introduction
The most important condition for the development of the country is the improvement of the system of training on the basis of economics, science, culture, engineering and technology. The national personnel training program is aimed at fundamental modernization of the structure and content of the lifelong education system.
The state policy in the field of personnel training provides for the formation of a diversified personality through a system of continuous education. A special place in the system of continuous education is occupied by higher education, which, on the basis of general secondary, secondary specialized, vocational education, is an independent type of continuous education and is carried out in accordance with the Law of the Republic of Uzbekistan “On Education” and the “National Program for Personnel Training”.
One of the defining tasks higher education in accordance with the National Program for Personnel Training is to ensure effective education and training of qualified personnel based on modern educational programs.
Among the disciplines that make up the basic training of chemists in the textile, light and paper industries, organic chemistry occupies an important place.
Organic chemistry - this branch of chemical science that studies carbon compounds, their structure, properties, methods of preparation and practical use.
Compounds containing carbon are called organic compounds. In addition to carbon, they almost always contain hydrogen, quite often - oxygen, nitrogen and halogens, less often - phosphorus, sulfur and other elements. However, carbon itself and some of its simplest compounds, such as carbon monoxide (II), carbon monoxide (IV), carbonic acid, carbonates, carbides, etc., by the nature of their properties, belong to inorganic compounds. Therefore, another definition is often used: organic compounds are hydrocarbons (compounds of carbon with hydrogen) and their derivatives.
Carbon stands out among all the elements in that its atoms can bind to each other in long chains or cycles. It is this property that allows carbon to form millions of compounds, the study of which is devoted to an entire field - organic chemistry.
The role of chemistry in the practical activity of man and in the development of technology is great. A deep knowledge of chemistry is necessary for specialists: along with physics and mathematics, it forms the basis for the professional training of highly qualified specialists.
ruleswork in the laboratory of organic chemistry andpreventive actionagainstaccidents
When conducting laboratory work in organic chemistry, one has to deal with combustible, flammable liquids and gases, strong acids and alkalis, and toxic substances. Therefore, the following instructions must be observed:
Before classes, the student needs to get acquainted in advance with the course of the experiments, clearly understand the goals and objectives of the work. It is possible to start performing experiments only after the student submits a preliminary report (name, brief description of the course of the experiment, reactions)
Keep the workplace clean and tidy.
It is forbidden to conduct experiments in dirty dishes, as well as to use substances from unlabeled bottles for experiments.
Work with toxic and strong-smelling substances, with concentrated solutions of acids, alkalis should be carried out in a fume hood
Do not pour out the excess reagent and do not pour it back into the bottle from which it was taken.
If there are no instructions on the dosage of reagents for a given experiment, then they should be taken in the smallest possible amount. Burning spirit lamps should not be left unnecessarily.
When working with acids, one must firmly remember the rules for mixing strong sulfuric acid with water - carefully pour acid into water in small portions while stirring, and not vice versa.
Do not sniff the released gases, leaning close to the bottle. If it is necessary to determine the smell of a gas or liquid, carefully inhale the air, slightly directing the stream of air from the opening of the vessel towards you.
Never blow on a burning spirit lamp. Extinguish it, covering it with a cap.
Do not work with flammable liquids near heating devices. It is forbidden to heat volatile flammable liquids, substances (ethers, alcohols, acetone) on an open flame. To do this, you must use a water bath.
When heating and boiling a test tube with a liquid, the opening of the test tube should be directed away from both the worker and others, in order to avoid the release of substances from the test tube.
Do not taste reagents.
In case of a burn, apply cotton wool moistened with a 5-10% solution of potassium permanganate or moistened with liquid from burns (from the first-aid kit) to the burned area.
In case of glass cuts, remove the fragments from the wound, disinfect with a solution of potassium permanganate KMnO4 or alcohol, lubricate the edges of the wound with iodine tincture, put sterilized gauze, absorbent cotton on the wound and tightly tie it with a bandage. After providing first aid, refer the victim to a doctor
If acids or alkalis get on the skin or clothes, you must first wash the affected area with plenty of water, then, in case of acid damage, rinse with 3% sodium bicarbonate solution, and in case of alkali, 1-2% acetic acid solution. After that again with water. The alkali is washed off with water until the area of the skin on which it has fallen is no longer slippery. Remove clothing that has come into contact with reagents.
In case of a burn with a hot liquid or a hot object, rinse the burned area with cold running water for 5-10 minutes. Then you should immediately deliver to the nearest medical facility
If acid splashes into the eye, it is washed with plenty of water so that it flows from the nose to the temple, and then with a 3% bicarbonate solution; in case of contact with alkali, they are washed first with water, then with saturated solutions of boric acid.
If the poison is ingested, it is necessary to induce vomiting by taking a warm solution of table salt (3-4 teaspoons per glass of water). Move the victim to fresh air.
Llaboratory work1
Eelementalanalysisorganic compoundseny
The composition of organic compounds includes: carbon, hydrogen, oxygen, relatively less often - nitrogen, sulfur, halides, phosphorus and other elements.
Organic compounds in most cases are not electrolytes and do not give characteristic reactions to the elements contained in them. In order to perform a qualitative analysis of organic matter, it is necessary to first destroy organic molecules by complete combustion or oxidation of them. In this case, simpler substances are formed, such as CO2, H2O, which are easily discovered by conventional analytical methods.
An experience1. Determination of carbon andhydrogenbut.
The presence of carbon in organic compounds can in most cases be detected by the charring of the substance when it is carefully ignited.
The most accurate method of discovering carbon and hydrogen at the same time is the combustion of organic matter mixed with a fine powder of copper (II) oxide. Carbon forms carbon dioxide with the oxygen of copper oxide, and hydrogen forms water. Copper oxide is reduced to metallic copper.
Experience Description. In a dry test tube with a gas outlet tube, fill one third with a mixture of starch (well-ground sugar can be used) with powdered copper (II) oxide, taken in excess (Fig. 1). Place a few crystals of anhydrous copper sulphate at the opening of the test tube. The test tube is fixed in a stand in a horizontal position, and the end of the gas outlet tube is inserted to the bottom into another test tube containing 2-3 ml of lime (or barite) water.
The reaction mixture is heated first gently, then more strongly for 3-5 minutes. After the completion of the experiment, first remove the end of the gas outlet tube from the test tube and stop heating. Note the changes in the crystals of copper sulphate and barite water. The formation of water droplets on the walls of the test tube and the gas outlet tube, as well as the blue vitriol (formation of CuSO4 * 5H2O) indicate the presence of hydrogen in the test substance, and the turbidity of lime or barite water indicates the presence of carbon (the formation of a precipitate of barium carbonate BaCO3 or calcium carbonate CaCO3) . Reaction equations:
(C6H10O5)n + 12CuO 6СО2 + 5Н2О + 12Сu
Сa(OH)2 + CO2 СaCO3v + H2О
CuSO4 + 5H2O CuSO4 * 5H2O
Rice. 1 Determination of carbon and hydrogen in a mixture of starch with copper (II) oxide:
1 - test tube
2 - gas outlet tube
3 - test tube with lime water
An experience2. Determination of nitrogen and sulfur.
Nitrogen in organic compounds can be detected in various ways. The most common method is the Prussian blue reaction.
To do this, the organic matter is calcined with metallic potassium or sodium. There is a complete decomposition of organic matter. Carbon, nitrogen and potassium (or sodium) form potassium cyanide (or sodium cyanide). The action of a small amount of iron sulphate converts the cyanide salt into iron cyanide. The latter gives a characteristic reaction of the formation of Prussian blue with ferric chloride:
2NaCN + FeSO4 = Fe(CN)2 + K2SO4
Fe(CN)2 + 4NaCN = Na4
3Na4 + 4FeCl3 = Fe43 + 12NaCl
Sulfur can be opened at the same time as nitrogen. When an organic substance containing sulfur is calcined with metallic sodium, sodium sulfide is formed:
The experiment is carried out in a fume hood behind glass or in safety goggles, following the instructions below., since an accident can occur if sodium metal is handled carelessly.
Experience Description. The experiment is carried out in a fume hood behind glass. A few crystals or a drop of the test substance are placed in a dry test tube. A small piece of metallic sodium, well purified from the outer layer, is also thrown there. Carefully heat the test tube on the flame of a burner, holding it in a wooden clamp. After a while there is a flash. The test tube is heated to red heat for some more time, and then the hot end of the test tube is immersed in a porcelain cup with 3-4 ml of distilled water (Caution! There may be a slight explosion from incompletely reacted metallic sodium!). In this case, the test tube cracks and the contents dissolve in water. The solution is filtered from pieces of coal and glass. To a part of the filtrate, a crystal of ferrous sulfate or 2-3 drops of its freshly prepared solution is added, boiling for one minute, then a drop of ferric chloride is added and acidified with hydrochloric acid. In the presence of nitrogen in the test substance, a blue precipitate of Prussian blue appears.
To detect the sulfur ion, part of the filtrate is acidified with hydrochloric acid. The characteristic smell of hydrogen sulfide indicates the presence of sulfur. Lead acetate is poured into the test tube with the remaining alkaline filtrate. In the presence of sulfur, a black precipitate of lead (II) sulfide PbS is formed, or in the case of a small amount of sulfur, the solution turns brown.
An experience3 . Qualitative reactionfor halogens.
TryBelstein.
For the discovery of halides, the flame coloring reaction proposed by the chemist F.F. Belshtein is often used. When organic matter is heated in the presence of copper oxide, as seen above, the organic matter burns out. Carbon and hydrogen forms carbon dioxide and water. Halides form salts with copper. These salts are easily volatile when heated and the vapors turn the flame a beautiful green color.
Description of experience. A copper wire with a diameter of 1-2 mm with a loop at the end is calcined in the colorless part of the burner flame until the coloring of the flame disappears. In this case, copper is covered with a black coating of copper oxide (II) CuO. Upon cooling the wire, the loop is immersed in a reagent containing a halogen, for example, in chloroform, or several grains of the test substance are collected and brought into the burner flame. In the presence of halogen, the flame turns a beautiful green color due to the formation of volatile copper halides. For cleaning, the wire is moistened with hydrochloric acid and ignited again. A control experiment should be made by lowering the wire into a liquid known to be halogen-free (distilled water, alcohol). Reaction equation:
2CHCI3 + 5CuO CuCI2 + 4CuCI + 2СО2 + Н2О
hydrocarbons
hydrocarbons - it's aboutorganic compounds made up of carbon and hydrogen. The classification of hydrocarbons is carried out according to the following structural features that determine the properties of these compounds:
1) the structure of the carbon chain (carbon skeleton);
2) the presence in the chain of multiple bonds С=С and С?С (degree
saturation).
1. Depending on the structure of the carbon chain, hydrocarbons are divided into two groups:
*acyclic ( or aliphatic, or fatty hydrocarbons;
*cyclic, characterized by the content in the molecule of rings or cycles of carbon atoms.
Carbon atoms are able to connect with each other in chains of various structures:
and different lengths: from two carbon atoms ( ethane CH3-CH3, ethylene CH2=CH2, acetylene CH?CH) to hundreds of thousands ( polyethylene, polypropylene, polystyrene and other macromolecular compounds).
An open (open) chain of aliphatic hydrocarbons can be unbranched or branched. Hydrocarbons with an unbranched carbon chain are called normal ( n-) hydrocarbons. Among the cyclic hydrocarbons are:
*alicyclic(or aliphatic cyclic);
*aromatic (arenas).
In this case, the structure of the cycle serves as a classification feature. Aromatic hydrocarbons include compounds containing one or more benzene rings.
2 . According to the degree of saturation, they distinguish:
*rich(marginal) hydrocarbons ( alkanes And cycloalkanes), in which there are only single bonds between carbon atoms and there are no multiple bonds;
*unsaturated(unsaturated), containing, along with single bonds, double and / or triple bonds ( alkenes, alkadienes, alkynes, cycloalkenes, cycloalkynes).
Llaboratory work2
Topic : « Limit hydrocarbons»
Alkanami - called aliphatic (alicyclic) limiting hydrocarbons(or paraffins), in the molecules of which the carbon atoms are interconnected by simple (single) bonds in undevelopedbranched and branched chains.
General formula of saturated hydrocarbons CnH2n+2, where n is the number of carbon atoms. The simplest representatives of alkanes:
When a hydrogen atom is detached from an alkane molecule, one-valve particles are formed, called hydrocarbon radicals (abbreviated as R). The names of monovalent radicals are derived from the names of the corresponding hydrocarbons with the replacement of the ending - en on the -ill. The general name for the monovalent radicals of alkanes is alkyls. They are expressed by the general formula СnН2n+1.
The formulas and names of the first ten members of the homologous series of alkanes and their normal radicals (alkyls) are given in Table 1
Table 1
|
Monovalent |
||||
To understand the properties of a molecule, it is necessary to take into account all the atoms adjacent to each carbon atom. A carbon atom bonded to one carbon atom is called primary , an atom bonded to two carbon atoms, - secondary , with three - tertiary , and with four Quaternary . Primary, secondary, tertiary and quaternary carbon atoms can also be distinguished by the degree of saturation of carbon atoms with hydrogen atoms.
Name construction example:
|
Objective: |
Get acquainted with the laboratory method for obtaining the first representative of the homologous series of saturated hydrocarbons and study its chemical properties. |
|
|
Equipment and reagents: |
Gas outlet tube with stopper, set of test tubes in a rack, spirit lamp, anhydrous sodium acetate CH3COONa, soda lime (mixture of powders of calcium oxide CaO with sodium hydroxide NaOH (3:1), saturated solution of bromine water Br2, 1% solution of potassium permanganate KMnO4 |
An experience1. Receiptand properties of methane
Methane can be obtained in the laboratory by fusing dry sodium acetate and caustic alkali.
Experience Description. In a mortar, dehydrated sodium acetate is thoroughly ground with soda lime (soda lime consists of a mixture of caustic soda and calcium oxide), mass ratio 1:2. The mixture is placed in a dry test tube (layer height 6x8 mm), closed with a gas outlet tube and fixed in a tripod.
Separately, 2x3 ml of potassium permanganate solution is poured into one test tube and acidified with 1-2 drops of concentrated sulfuric acid, and 2 ml of bromine water into another test tube.
The mixture in a test tube is heated in the flame of an alcohol lamp, and the end of the gas outlet tube is alternately introduced into solutions of potassium permanganate and bromine water. The passage of gas is carried out for 20 h 30 s. After that, the vent tube is turned upside down and the gas is ignited at the end of the vent tube. The color of these solutions does not change, therefore, methane does not react with the taken substances.
Without stopping heating, collect the evolved gas. To do this, fill an empty test tube with water and tip it into a cup of water. Bring the end of the gas outlet tube under the test tube and fill it with gas. Without removing the test tubes from the water, close it with your finger and then bring it to the flame of the burner. The ignited gas burns with a bluish flame. Reaction equations:
Llaboratory work3
Topic : "Unsaturated hydrocarbons. Alkenes»
Alkenes (olefins, or ethylene) called unsaturated hydrocarbons containing one double bond in the molecule and having the general formulaCnH2n.
A double bond consists of one y-bond and one p-bond, which is less strong and therefore easily broken during chemical reactions.
Carbon atoms in the sp2 hybridized state are involved in the formation of such a bond. Each of them has three 2sp2-hybrid orbitals directed to each other at an angle of 120°, and one unhybridized 2p-orbital located at an angle of 90° to the plane of the hybrid atomic orbitals AO.
An experience1. ReceiptAndproperties of ethylene.
Ethylene can be obtained from ethyl alcohol by removing water:
CH2 - CH2 CH2 = CH2 + H2O
This reaction proceeds by the interaction of alcohol with sulfuric acid in two phases:
1) the formation of ethylsulfuric acid when alcohol is mixed with acid:
C2H5OH + H2SO4 CH3 - CH2 - O - SO3H + H2O
2) elimination of sulfuric acid when the mixture is heated to 1700C:
CH3 - CH2 - O -SO3H H2SO4 + CH2 = CH2
Ethylene, as an unsaturated hydrocarbon, easily reacts with addition, for example, with bromine:
CH2 CH2 + Br2 CH2 - CH2
1,2-dibromoethane
Upon addition, bromine decolorizes, so this reaction is used as qualitative reaction to the double bond. The oxidation of ethylene also occurs very easily.
With careful oxidation in an aqueous solution, oxygen and a water molecule are added to form a dihydric alcohol - glycol:
3CH2 = CH2 + 2KMnO4 + 4H2O > 3CH2 - CH2 + 2MnO2v + 2KOH
ethene (s) | |
ethylene (p) OH OH
ethanediol-1,2 (c)
ethylene glycol (r)
The oxidizing agent is usually a weak solution of potassium permanganate. This reaction is called Wagner reactions. In this reaction, potassium permanganate is reduced to manganese (IV) oxide and the solution turns brown. This reaction can also serve as a qualitative reaction to unsaturated hydrocarbons.
Rice. 2 Device for obtaining ethylene:
1 - burner, 2 - test tube with mixture, 3 - plug, 4 - tripod, 5 - gas outlet tube, 6 - test tube with bromine water (or potassium permanganate)
Experience Description. About 5 ml of a mixture consisting of one part of ethyl alcohol and three parts of concentrated sulfuric acid is poured into a test tube with a gas outlet tube. The mixture is gently heated (Fig. 2).
Attention! The mixture is dangerous! Put a piece of pumice stone or dry sand there (for even boiling when heated). Pass the released gas through solutions of potassium permanganate and bromine water. There is a discoloration of bromine water and the reduction of potassium permanganate. The collected gas is ignited.
Reaction equation:
CH2 CH2 + 3O2 2CO2 + 2H2O
Llaboratory work4
Topic : “Unsaturated hydrocarbons. Alkiny"
Alkynes (or acetylenic hydrocarbons) called unsaturated (unsaturated) aliphatic hydrocarbons, the molecules of which, in addition to single bonds, contain one triple bond between carbon atoms.
These hydrocarbons are even more unsaturated compounds than their corresponding alkenes (with the same number of carbon atoms). This can be seen from a comparison of the number of hydrogen atoms in the series:
ethane ethylene acetylene (ethene) (ethyne)
When a triple bond is formed, two electrons of the outer layer participate ( s- And p-) forming two hybrid sp-orbitals. The resulting hybrid orbitals overlap each other and the orbitals of the hydrogen atom, forming triple bond , consisting of one at- and two
R- connections (valence angle 1800). Therefore, they talk about the linear structure of acetylenic hydrocarbons.
An experience1 . ReceiptAndpropertiesbutacetylene.
Acetylene is obtained in a test tube with a gas outlet tube by the action of water on a piece of calcium carbide (Fig. 3).
The reaction proceeds according to the following equation:
C? C + 2H2O HC? CH + Ca(OH)2
Calcium carbide usually contains impurities of phosphorous compounds, which give poisonous hydrogen phosphide under the action of water, so the reaction for producing acetylene must be carried out in a fume hood.
Rice. 3 Device for obtaining acetylene:
1- test tube - reactor
2- vent pipe
The resulting acetylene is passed through pre-prepared solutions: a solution of potassium permanganate acidified with sulfuric acid, bromine water, an ammonia solution of copper (I) chloride.
Acetylene attaches bromine and is easily oxidized with potassium permanganate. The bromine addition reaction proceeds in two stages:
HC CH + Br2 CHBr = CHBr CHBr2 - CHBr2
ethyne 1,2-dibromoethene 1,1,2,2-tetrabromoethane
The oxidation reaction of acetylene is very complex with the splitting of the molecule. When interacting with a solution of potassium permanganate KMnO4, the raspberry solution becomes discolored. This is another qualitative reaction for the presence of a p-bond in an organic compound.
a) partial oxidation:
3HC? CH + 4KMnO4 + 2H2O > 3 + 4MnO2 + 4KOH
glyoxal
(dialdehyde)
b) complete oxidation
HC? CH + [O] + H2O > HOOC - COOH
acetylene oxalic acid
Just as in previous experiments, the combustion of acetylene in air is studied. Description of experience. About 1 ml of water is poured into a test tube and a piece of calcium carbide is dropped. Quickly close the hole with a stopper with a gas outlet tube. The reaction is violent and fast. To slow down the reaction, you can add one drop of dilute sulfuric acid to 3-4 drops of poured water. The released gas is passed through pre-prepared solutions of potassium permanganate and bromine water. Then collect the gas and set it on fire. Hold a piece of glass high above the flame of burning acetylene. Acetylene burns with the formation of soot (with a lack of air supply) or a luminous flame (a sign of unsaturation of the compound). The combustion reaction of acetylene:
2HC CH + 5O2 4CO2 + 2H2O
halo derivativeIEALIPHATIC HYDROCARBONS (HALOIDALKYLS)
Halogen derivatives of aliphatic hydrocarbons can be considered as derivatives of hydrocarbons in which one or more hydrogen atoms are replaced by halogen atoms. Depending on the substitution of one, two, three, etc. atoms into halides distinguish between monohalo derivatives and polyhalo derivatives.
The name of the simplest halogen derivatives is usually compiled by analogy with the name of inorganic salts of hydrohalic acids with the designation of their constituent radicals. For example, CH3Cl is methyl chloride, etc.
Halogen can replace hydrogen at various carbon atoms in the chain. If the halogen is at the carbon bonded to one carbon atom, the halogen derivative is called primary; for example, the compound CH3-CH2-Cl is called primary ethyl chloride. If the halogen is at the carbon bonded to two carbon atoms, the halogen derivative is called secondary, for example, the compound:
called secondary butyl chloride (2-chlorobutane). And, finally, if the halogen stands at the carbon bonded to three carbon atoms, the halide derivative is called tertiary, for example, the compound:
called tertiary isobutyl chloride (2-methyl 2-chloropropane). All three compounds are isomeric. It can be seen from these examples that both chain isomerism and halogen position isomerism take place for halogen derivatives. Unlike saturated hydrocarbons, their halogen derivatives are reactive compounds due to the presence of a polar bond between carbon atoms and a halogen. They can easily exchange a halogen atom for other atoms or groups of atoms, such as -OH, -CN, -NH2, etc.
Llaboratory work5
Synthesis of ethyl bromide
Ethyl bromide can be obtained by one of the general methods for obtaining halide derivatives by the action of hydrohalic acids on alcohols:
C2H5OH + HBr > C2H5Br + H2O
In practice, potassium bromide is taken instead of hydrogen bromide and sulfuric acid. Formed as a result of the interaction of these substances - hydrogen bromide, reacts with alcohol. The reaction is reversible. To direct it towards the formation of ethyl bromide, an excess of sulfuric acid is taken, which binds the water formed during the reaction.
Part of the alcohol reacts with sulfuric acid, forming ethylsulfuric acid, which then, reacting with hydrogen bromide, also forms ethyl bromide. The reaction proceeds according to the following equation:
CH3CH2OH + HO- SO3H > CH3CH2 OSO3H + H2O
CH3CH2OSO3H + HBr > CH3CH2Br + H2SO4
Description experience. Pour 5 ml of ethyl alcohol into a flask with a capacity of 100 ml through a dropping funnel and then in small portions 5 ml of concentrated sulfuric acid. Since heating occurs in this case, the flask with the mixture is cooled with water, after which 3.5 ml of water is poured into it drop by drop and 5 g of potassium bromide are added. The flask is then closed with a cork stopper and attached to a refrigerator connected to the allonge. The end of the allonge is lowered into a flask with water so that it is immersed in water by about 1-2 mm. Before starting the reaction, several pieces of ice are thrown into the receiver to better cool the easily evaporating ethyl bromide.
The reaction mixture is carefully heated on an asbestos grid to a boil, not allowing the liquid to foam strongly, otherwise it may be thrown into the receiver. The reaction starts fairly quickly, as can be seen from the heavy oily drops of ethyl bromide falling to the bottom of the flask. When the droplets of ethyl bromide have nearly stopped falling, the heating is stopped.
The resulting ethyl bromide is separated from the aqueous layer. To do this, the entire mixture is transferred to a separating funnel and, carefully opening the tap, the lower oily layer is poured into the prepared clean test tube and immediately closed with a stopper.
Ethyl bromide is a heavy colorless liquid with a sweet smell, density 1.486 and boiling point 38.40C. Write the reaction equation. Do a Bellstein test for the presence of halogen. The received preparation should be handed over to the teacher.
Llaboratory work6
Topic : "Aromatic hydrocarbons"
Arenas (or aromatics) - this connections, whose molecules contain stable cyclic groups of atoms (benzene nuclei) with a special nature of chemical bonds.
The simplest representatives:
single core arenas:
multi-core arenas:
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Naphthalene Anthracene
Benzene is a colorless, mobile liquid with a boiling point of 80.10C, which solidifies on cooling into colorless crystals with a melting point of 5.530C, and has a peculiar smell. Easily ignited and burns with a smoky flame. Judging by the summary formula, it can be assumed that benzene is a highly unsaturated compound, similar to, for example, acetylene.
However, the chemical properties of benzene do not support this assumption. So, under normal conditions, benzene does not give reactions characteristic of unsaturated hydrocarbons: it does not enter into addition reactions, does not decolorize a solution of potassium permanganate KMnO4.
In a benzene molecule, all carbon and hydrogen atoms lie in the same plane, and the carbon atoms are located at the vertices of a regular hexagon with the same bond length between them, equal to 0.139 nm. All bond angles are 120.
This arrangement of the carbon skeleton is due to the fact that all carbon atoms in the benzene ring have the same electron density and are in the sp2 hybridization state.
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Goalswork: |
To study some physical and chemical properties of benzene and its homologues. Compare the reactivity of benzene and toluene. To get acquainted with the properties of polynuclear aromatic compounds using the example of naphthalene |
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equipment and rnon-assets: |
Outlet tube, set of test tubes, porcelain cup, three 100 ml beakers, spirit lamp, Wurtz flask, C6H6 benzene, naphthalene, concentrated H2SO4 sulfuric acid, HNO3 concentrated nitric acid, Br2 saturated bromine water solution, 1% KMnO4 potassium permanganate solution, sodium hydroxide NaOH, calcium chloride CaCl2. |
An experience1 . Reaction of benzene with bromine and potassium permanganate.
Pour 0.5 ml of benzene into two test tubes. 1 ml of bromine water is added to one of them, a few drops of potassium permanganate are added to the other. The mixture is shaken vigorously and allowed to settle.
Record your observations and explain.
Synthesis."Nitration of benzene"
Descriptionwork. ABOUTtests are carried out in a fume hood, as nitrobenzene vapors are poisonous. 25 ml of concentrated H2SO4 sulfuric acid is poured into a 100 ml flask equipped with cooling (40x50 cm3) and 20 ml of concentrated HNO3 nitric acid is carefully poured by drop method. The mixture is cooled to room temperature and 18 ml of benzene are added while stirring (an emulsion is formed). When nitrating benzene, make sure that the temperature of the reaction mixture does not exceed 500C and is not lower than 250C. The reaction is carried out in a water bath with a thermostat. The nitration reaction is continued for 45 minutes. at a temperature of 600C. After that, the reaction mixture is cooled with cold water and separated using a separating funnel. Nitrobenzene is at the bottom of the separating funnel. The nitrobenzene is then washed with a dilute sodium hydroxide solution and cold water. The washed nitrobenzene is poured into a conical flask and calcined calcium chloride is added. The flask is stoppered with an air cooler and heated in a water bath until a clear liquid is formed. The dried nitrobenzene is poured into an air-cooled Wurtz flask and distilled at a temperature of 207-2110C. Benzene yield 22 g.
Nitrobenzene is a yellow oily liquid with a bitter almond odor. Nitrobenzene does not dissolve in water, but dissolves in alcohol, benzene, ether. Molecular weight 123.11, boiling point 210.90C.
Couples nYitrobenzene poisonous, so after experiencehis must be drained into a specialwow bottleat.
An experience3 . Sulfonationaromatic hydrocarbons.
Experience Description. 3 drops of toluene are placed in two test tubes, and a few crystals of naphthalene are placed in the second. 4-5 drops of concentrated sulfuric acid are poured into each test tube and heated in a boiling water bath with constant shaking for 10 minutes. Naphthalene partially sublimates and crystallizes on the walls of the test tube above the liquid level; it must be remelted by heating the entire test tube. Record the time required to obtain a homogeneous solution.
After that, the tube is cooled in cold water and 0.5 ml of water is added to it. If the sulfonation is complete, a clear solution is formed, since sulfonic acids are highly soluble in water. Write the reaction equations for the sulfonation of toluene and naphthalene at different temperatures.
Oxygenated organic compounds
There are a huge number of organic compounds, which, along with carbon and hydrogen, include oxygen. The oxygen atom is contained in various functional groups that determine whether the compound belongs to a particular class.
LlaboratoryJob7
Topic : "Alcohols"
alcohols organic substances are called, the molecules of which contain one or more hydroxo groups connected to a hydrocarbon radical.
The hydroxo group is a functional group of alcohols. Depending on the nature of the hydrocarbon radical, alcohols are divided into aliphatic (limiting and unsaturated) and cyclic.
Alcohols are classified according to various structural features:
1. According to the number of hydroxo groups (atomicity) in the molecule, alcohols are divided into one-, two-, three-atomic, etc.
For example:
In polyhydric alcohols, primary, secondary, and secondary and tertiary alcohol groups are distinguished. For example, a molecule of the trihydric alcohol glycerol contains two primary alcohol (HO-CH2-) and one secondary alcohol (-CH(OH)-) groups.
2. Depending on which carbon atom the hydroxo group is attached to, alcohols are distinguished:
primary R-CH2-OH
secondary R1 - CH - R2
tertiary R1 - C - R3
where R1, R2, R3 are hydrocarbon radicals, may be the same or different.
3. According to the nature of the hydrocarbon radical associated with the oxygen atom, the following alcohols are distinguished:
? marginal, or alkanols containing only saturated hydrocarbon radicals in the molecule, for example,
2-methylpropanol-2
? unlimited, And whether alkenols containing multiple (double or triple) bonds between carbon atoms in the molecule, for example:
CH2=CH-CH2-OH HC? C - CH - CH3
? aromatic, those. alcohols containing a benzene ring and a hydroxo group in the molecule, connected to each other not directly, but through carbon atoms, for example:
Phenylcarbinol (benzyl alcohol)
An experience1. Solubility of alcohols in water
The simplest monohydric alcohols are highly soluble in water. Solubility decreases as molecular weight increases. The solubility of polyhydric alcohols increases with an increase in the number of hydroxo groups. Aqueous solutions of alcohols have a neutral environment.
Experience Description. Pour a few drops of methyl, ethyl and isoamyl alcohols into separate tubes and add 2-3 ml of water to each tube. Shaken. Note the presence or absence of layers. Determine the solubility of alcohols.
Test alcohol solutions on litmus paper. No color change occurs. Write the structural formulas of the taken alcohols.
test questionsand exercises:
Experience 2.Obtaining sodium alcoholate
Monohydric alcohols as neutral compounds do not react with aqueous solutions of alkalis. Hydrogen of the hydroxo group can only be displaced by metallic potassium or sodium to form compounds called alcoholates, for example:
2C2H5OH + 2Na 2C2H5ONa + H2^
This compound is highly soluble in alcohol. Under the action of water, it decomposes with the formation of alcohol and alkali:
C2H5ONa + H2O C2H5OH + NaOH (pH>7)
Description of experience. A small piece of sodium metal, purified and dried with filter paper, is thrown into a test tube with 1 ml of anhydrous ethanol, and the opening of the test tube with a gas outlet tube is closed. ( If heating leads to the boiling of alcohol, then the mixture is cooled in a glass of cold water.). The escaping gas is ignited. If the sodium has not completely reacted, then an excess of alcohol is added, bringing the reaction to completion.
After all the sodium has reacted, the tube is cooled and 3-4 drops of water and 1 drop of phenolphthalein are added. Test the solution with litmus paper. organic hydrocarbon aldehyde ketone
Experience 3.Getting glyceratecopper (II)
In polyhydric alcohols, the hydrogens of hydroxo groups are more easily replaced by metals than in monohydric alcohols. So, for triatomic alcohols - glycerols, the corresponding metal derivatives - glycerates are obtained even when heavy metal oxides and their hydrates, for example, copper oxide hydrate, act on glycerin. This indicates that, unlike monohydric alcohols, polyhydric alcohols have weak acidic properties.
Description of experience. Prepare copper(II) hydroxide. To do this, about 1 ml of a 10% solution of copper sulfate (CuSO4) is poured into a test tube and a little 10% solution of sodium hydroxide (NaOH) is added until a precipitate of copper hydroxide forms. Glycerol is added dropwise to the resulting precipitate and the tube is shaken. The precipitate dissolves and a dark blue solution is obtained. The reaction equation for the formation of copper glycerate:
CuSO4 + 2NaOH Cu(OH)2v + Na2SO4
LlaboratoryJob8
Topic: « Fenoly"
Phenols called derivatives of aromatic hydrocarbons, whose molecules contain one or more hydroxogroups -OH, directly connected with carbon atoms benzene ring.
Depending on the number of hydroxo groups, they are distinguished: monatomic phenols and polyatomic phenols.
phenol 1,2-dioxybenzene 1,3-dioxybenzene 1,4-dioxybenzene
about-dioxybenzene m-dioxybenzene P-Dioxybenzene (pyrocatechin) (resorcinol) (hydroquinone)
1,2,3-trioxybenzene 1,3,5-trioxybenzene 1,2,4-trioxybenzene (pyrogallol) (fluroglucinol) (hydroxyhydroquinone)
Phenols, unlike alcohols, are slightly acidic. This is expressed in the fact that they easily react with alkalis, forming compounds similar to alcoholate, called phenolates. The simplest phenol is called carbolic acid. For phenols, in addition to the reactions of substitution of the hydrogen of the hydroxo group, reactions of hydrogen substitution in the benzene ring are characteristic, for example, the reaction of halogenation, nitration and sulfonation. These reactions proceed more easily than in benzene, since the presence of a hydroxo group in the nucleus sharply increases the mobility of hydrogen atoms in the ortho and para positions.
Experience 1.actechlorideglandon thephenols
Phenols, both monatomic and polyhydric, give a characteristic color when a solution of ferric chloride is added. This reaction is qualitative breakdown for phenol.
INattention!Phenol is caustic.When working withhimit can't be allowed contact with skin, it causes burns.
Description of experience. In a test tube with 0.5 ml of phenol solution add 2-3 drops of 1% iron (III) chloride solution. Similar experiments are carried out with aqueous solutions of resorcinol, pyrogallol and hydroquinone. Phenol and resorcinol solutions turn purple, pyrogallol solution - brown-red. Hydroquinone does not give a characteristic coloration with ferric chloride, as it is easily oxidized by it to form quinone. Explain the observation. Reaction equations:
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An experience2 . Receiptphenolatesodium.
Experience Description. Pour a few ml of phenol emulsion into a test tube. Add carefully, drop by drop, a solution of caustic soda until the phenol is completely dissolved. Sodium phenolate is formed. To the resulting phenolate, add dropwise a 10% solution of sulfuric acid until an acidic reaction. In this case, phenol will again be released in the form of an emulsion. Reaction equations:
An experience 3 . Brominationphenol.
Description of experience. Pour 5 ml of a 1% phenol solution into a dry test tube and, with constant shaking, add a saturated solution of bromine water until a precipitate forms. Reaction equation:
LlaboratoryJob9
Topic : « Aldehydes and ketones»
Aldehydes and ketones are carbonyl compounds.
Aldehydes - this organic compounds in which the carbon atom of the carbonyl group linked to a hydrogen atom and a hydrocarbon radical.
General formula:
where, is the functional group of aldehydes,
R - hydrocarbon radical
Ketones - it's aboutorganic substances whose molecules contain a carbonyl group connected to two hydrocarbon radicals. General formula:
where R, R" are hydrocarbon radicals, may be the same or different.
ethylacetic aldehyde (p) dimethylacetic aldehyde (p)
3-methylpentanal (c) secondary isobutyl acetaldehyde (p)
methylpropylketone (p) methylisopropylketone (p)
CH3 - CH2- C - CH2 - CH3
pentanol -3 (c)
diethyl ketone (r)
An experience1. Receiptaceticaldehydeoxidationethanol.
Experience Description. In the flame of an alcohol lamp, a copper wire with a loop at the end is oxidized, red-hot, then it is quickly lowered into a test tube with alcohol and the tube is closed with a cork.
There is a reduction of copper oxide to metallic copper and the oxidation of alcohol to aldehyde. Save the resulting aldehyde solution for further experiments. Reaction equation:
CH3 -CH2-OH + CuO + Cu + H2O
An experience2. Reactionsilvermirrorson thealdehyde.
Aldehydes are easily oxidized, sometimes even by atmospheric oxygen, as well as oxides of silver and copper metals. In this case, acids are formed with the same number of carbon atoms in the chain.
The oxidation reaction of aldehydes by the action of silver oxide is the most sensitive to the aldehyde group (silver mirror reaction). The reagent is an ammonia solution of silver oxide hydrate. In this reaction, the aldehyde is oxidized to an acid, and silver oxide is reduced to metallic silver:
2OH + 2Agv + 4NH3^ + 2H2O
Ketones do not give a silver mirror reaction, since they are much more difficult to oxidize. They can be oxidized by stronger oxidizing agents, such as potassium permanganate. In this case, the ketone molecule is split and two acid molecules are formed.
Experience Description. A few drops of an ammonia solution of silver oxide are added to the aldehyde solution obtained in the previous experiment. The test tube is slightly heated. If the glass of the test tube is clean enough, the silver reduction is deposited on the walls in the form of a mirror. If the glass is dirty, a black precipitate of metallic silver will form. Write the reaction equation.
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MINISTRY OF HIGHER AND SECONDARY SPECIAL EDUCATION OF THE REPUBLIC OF UZBEKISTAN
A.KARIMOV, N.CHINIBEKOVA
WORKSHOP
IN ORGANIC CHEMISTRY
Textbook for students of pharmaceutical institutes
Tashkent -2009
Reviewers:
Akhmedov K. - Doctor of Chemical Sciences, Professor of the Department
Organic Chemistry of the Uzbek National
university
Kurbonova M. - Candidate of Pharmaceutical Sciences, Associate Professor of the Department
inorganic, analytical and physical colloid chemistry
Tashkent Pharmaceutical Institute
Introduction
I. TECHNIQUE OF LABORATORY WORKS
I.1 Laboratory safety and first aid measures
I.2 Chemical glassware and accessories
I.3 Basic operations when working in an organic chemistry laboratory
I.3.1 Heating
I.3.2 Cooling
I.3.3 Grinding
I.3.4 Mixing
I.3.5 Drying
I.4. Methods for isolating and purifying substances
I.4.1 Filtering
I.4.2 Crystallization
I.4.3 Sublimation
I.4.4 Distillation
I.5 Essential physical constants
I.5.1 Melting point
I.5.2 Boiling point
II. methods for determining the structure of organic compounds
II.1 Qualitative elemental analysis of organic compounds
III fundamentals of the structure, properties and identification of organic compounds
III.1 Classification, nomenclature, spatial structure and isomerism of organic compounds
III.2 Chemical bond and mutual influence of atoms in organic compounds
III.3 Alkanes. Cycloalkanes
III.4 Alkenes, alkadienes, alkynes
III.5 Arenas
III.6 Halogenated hydrocarbons
III.7 Alcohols
III.8 Phenols
III.9 Ethers
III.10 Aldehydes. Ketones
III.11 Amines
III.12 Diazo-, azo compounds
III.13 Monobasic and dibasic carboxylic acids
III.14 Heterofunctional carboxylic acids
III.14.1 Hydroxy-, phenolic acids
III.14.2 Oxoacids
III.14.3 Amino acids. Amides. Acid ureides
III.15 Five-membered heterocyclic compounds
III.15.1 Five-membered heterocyclic compounds with one heteroatom
III.15.2 Five-membered heterocyclic compounds with two heteroatoms
III.16 Six-membered heterocyclic compounds
III.16.1 Six-membered heterocyclic compounds with one heteroatom
III.16.2 Six-membered heterocyclic compounds with two heteroatoms
III.17 Fused heterocyclic compounds
III.18 Carbohydrates
III.18.1 Monosaccharides
III.18.2 Polysaccharides
III.19 Saponifiable and unsaponifiable lipids
IV syntheses of organic compounds
IV.1 Halogenation
IV.1.1 1-Bromobutane
IV.1.2 Bromoethane
IV.1.3 Bromobenzene
IV.2 Sulfonation
IV.2.1 p-Toluenesulfonic acid
IV.2.2 p-Toluenesulfonic acid sodium
IV.2.3 Sulfanilic acid
IV.3 Acylation
IV.3.1 Acetic acid ethyl ester
IV.3.2 Acetylsalicylic acid
IV.3.3 Acetanilide
IV.4 Preparation of glycosides
IV.4.1 N-glycoside of white streptocide
V. Literature
INTRODUCTION
Organic chemistry occupies an important place in the system of higher pharmaceutical education, being one of the fundamental sciences that form the scientific, theoretical and experimental basis both for mastering special knowledge in pharmaceutical chemistry, pharmacognosy, pharmacology, toxicological chemistry, and for the professional activities of a pharmacist. The use of this knowledge when performing qualitative reactions to functional groups, obtaining individual representatives of various classes of organic compounds, carrying out characteristic reactions with them contributes to a deeper assimilation of theoretical material.
Today, the development of organic chemistry is accompanied by the appearance of a huge number of new substances: in the general list medicines, over 90% are organic matter. This, in turn, predetermines the need for knowledge and improvement of experimental techniques and research methods. In this regard, the training of pharmaceutical specialists who need knowledge of organic chemistry requires not only theoretical training, but also versatile practical skills and abilities in conducting a chemical experiment.
Workshop on Organic Chemistry" is a logical continuation of the lecture course on this subject and is a single educational and methodological complex that contributes to creativity to the study of the discipline, conducting practical classes, taking into account modern teaching methods (interactive, innovative). This manual allows you to get acquainted with some methods for obtaining individual representatives of the classes of organic chemistry in the laboratory with small amounts of starting materials, reagents and relatively simple equipment.
The workshop included in almost every topic is aimed at ensuring that the student can see in the experiment the manifestation of the most important chemical properties characteristic of the functional groups that determine the reactivity of the compound. Indeed, in professional activities, sometimes with the help of outwardly simple chemical samples, the authenticity of a medicinal substance will be determined, the question of the presence or absence of one or another component in the mixture, etc. will be decided. It is important to understand what chemical processes cause the manifestation of an external effect (the appearance of coloration, smell, etc.).
This guide embodies the experience of many years of work of the staff of the Department of Organic Chemistry of the Tashkent Pharmaceutical Institute, on the basis of which the structure of the workshop for students of the pharmaceutical specialty is determined.
The workshop includes four sections and a list of recommended literature.
The first section, devoted to the technique of laboratory work, provides information on chemical glassware and auxiliary devices, discusses the main operations of practical work, methods for isolating and purifying substances, and determining the most important physical constants.
In the second section, methods for determining the structure of organic compounds are considered, and a qualitative elemental analysis of the study of the structure of organic substances is given.
The third section includes information about the structure, properties and identification of organic compounds. For each topic, general theoretical questions and answers to them, control questions and exercises, and practical experiments with a detailed description of the ongoing chemical processes are given.
The fourth section lists the syntheses of some organic compounds available for laboratory use.
I. TECHNIQUE OF LABORATORY WORKS
I.1 LABORATORY SAFETY AND FIRST AID MEASURES
GENERAL SAFETY RULES FOR WORK IN CHEMICAL LABORATORIES
When working in an organic chemistry laboratory, a student must clearly understand the specifics of organic compounds, their toxicity, flammability, which requires especially careful handling and compliance with certain rules.
1. In the laboratory, a student works in a dressing gown that fastens at the front (the gown is easy to remove in case of ignition). At the workplace, in addition to a rack with test tubes and reagents, there is only a working diary and a soft napkin.
2. Before starting work, you need to carefully study its description, know the properties of the substances obtained.
3. When performing work, you must be careful and careful. Carelessness, ignorance of the properties of substances with which the student will work, can lead to an accident.
4. When heating chemicals in a test tube, it is necessary to fix it in an inclined state so that its opening is directed in the direction opposite from oneself and not in the direction of the comrades working nearby. Heat the test tube gradually, moving the flame of the burner through the test tube from top to bottom.
5. When working with a gas outlet tube, the heating of the test tube can be stopped only by first removing the end of the tube from the receiver with liquid. If the heat source is removed prematurely, the liquid from the receiver may be sucked into the reaction tube and it may burst, and the reaction mixture may be splashed onto the face and hands.
6. No substances in the laboratory can be tasted.
7. When determining the smell, pairs from a test tube or flask are directed towards themselves with a movement of the hand.
8. All experiments with substances with a sharp irritating odor should be carried out only under draft.
9. Sodium metal is cut with a sharp, dry knife on filter paper. Scraps, leftovers are immediately removed into special bottles filled with dry kerosene or vaseline oil. The reaction with metallic sodium should be carried out in a completely dry vessel.
10. Combustible and flammable liquids (ether, benzene, alcohol) are poured away from fire, test tubes and flasks with them are heated in a water or sand bath.
11. When igniting a liquid in a vessel, it is necessary, first of all, to extinguish the heat source, and then cover the flame with a napkin or cup. If a burning liquid spills on a table or on the floor, extinguish it only with sand or cover it with a dense piece of cloth. It is not recommended to use water for extinguishing, since organic substances, as a rule, do not mix with water and spread along with it, spreading the flame.
12. When clothing catches fire, it is necessary to immediately cover the burning with a blanket or thick outer clothing.
13. When diluting sulfuric acid with water, sulfuric acid should be added in a thin stream to water (and not vice versa) with continuous stirring of the solution.
14. It is forbidden to take alkali metals (potassium, sodium, their hydroxides) with bare hands, as well as to suck in acids, alkalis and solvents by mouth.
15. Bottles with common use reagents should always be on common shelves.
16. The remains of flammable liquids, acids, alkalis should not be poured into the sink, but into special bottles.
17. After finishing work and handing it over to the teacher of the workshop, the student is obliged to put his workplace in order, check whether electrical appliances, water, gas are turned off.
FIRST AID
Each laboratory for first aid should have a first aid kit with absorbent cotton, sterile swabs and bandages, adhesive plaster, 3-5% alcohol solution of iodine, 1% acetic acid solution, 1-3% solution of bicarbonate of soda, 2% solution of boric acid, glycerin , petroleum jelly, ointment for burns, ethyl alcohol, ammonia.
1. Burns from fire or hot objects are quickly treated with ointment from burns, then cotton is applied with this ointment and loosely bandaged. Potassium manganese and alcohol are also used for pre-treatment of the burned area. With severe burns, the victim is sent to the outpatient clinic.
2. In case of chemical burns (skin contact with acid, alkali or bromine), the affected area is washed with plenty of water, then with a 3% solution of bicarbonate of soda, lubricated with burn ointment or petroleum jelly and bandaged. The area of skin that has got alkali is immediately washed with plenty of water, then with a 1% solution of acetic acid, lubricated with burn ointment or petroleum jelly and bandaged. If bromine gets on the skin, immediately wash it with benzene, gasoline or a saturated solution of hyposulfite.
3. If acid gets into the eye, it is immediately washed with plenty of water, then with a dilute solution of soda, again with water, and the victim is immediately sent to the outpatient clinic.
4. If alkali gets into the eye, it is immediately washed with plenty of water, then with a dilute solution of boric acid, and the victim is immediately sent to the outpatient clinic.
5. The fabric of clothing that has been exposed to acid or alkali is washed with plenty of water, then treated with a 3% solution of bicarbonate of soda (in case of acid ingress) or a 1% solution of acetic acid (in case of alkali).
6. Hand cuts with glass are washed with a strong stream of water, fragments are removed from the wound, poured with an alcoholic solution of iodine and bandaged.
I.2 CHEMICAL GLASSWARE AND ACCESSORIES
The main laboratory chemical glassware includes flasks, glasses, test tubes, cups, funnels, refrigerators, dephlegmators and other vessels various designs. Chemical utensils are made of glass of various grades, they are resistant to different temperatures, to the effects of most chemicals, transparent, easy to clean.
Flasks, depending on the purpose, are made in various volumes and shapes (Fig. 1.1).
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Rice. 1.1. Flasks: a) round-bottomed, b) flat-bottomed, c) round-bottomed with two and three angled necks, d) conical (Erlenmeyer flask, e) Kjeldahl flask, f) pear-shaped, g) pointed-bottomed, h) round-bottomed for distillation (Wurtz flask) , i) sharp-bottomed for distillation (Claisen flask), j) Favorsky flask, l) flask with a tube (Bunsen flask).
organic chemistry synthesis compound
Round bottom flasks are designed for high temperature, atmospheric distillation and vacuum applications. The use of round-bottom flasks with two or more necks makes it possible to perform several operations simultaneously in the synthesis process: use a stirrer, refrigerator, thermometer, dropping funnel, etc.
Flat-bottomed flasks are only suitable for atmospheric pressure and storage liquid substances.
Conical flat-bottomed flasks are widely used for crystallization because their shape provides a minimum evaporation surface.
Thick-walled conical flasks with a tube (Bunsen flasks) are used for vacuum filtration up to 1.33 kPa (10 mm Hg) as filtrate receivers.
Glasses (Fig. 1.2, a) are designed for filtration, evaporation (at a temperature not exceeding 1000C), preparation of solutions in laboratory conditions, as well as for carrying out some syntheses, in which dense precipitates are formed that are difficult to remove from flasks. Glasses are not used when working with low-boiling and flammable solvents.
Rice. 1.2. Chemical glassware: a) glass, Fig. 1.3. Porcelain cup b) bottles
Bottles (Fig. 1.2, b) are used for weighing and storing volatile, hygroscopic and easily oxidized substances in air.
Cups (Fig. 1.3) are used for evaporation, crystallization, sublimation, drying, grinding and other operations.
Test tubes (Fig. 1.4) are produced with different capacities and are used for the analysis of test substances in small quantities. Test tubes with a conical section and a drain tube are used for filtering small volumes of liquids under vacuum.
To measure the volume of liquid, volumetric utensils are used: measuring cups, cylinders, volumetric flasks, pipettes, burettes (Fig. 1.5).
Rice. 1.4. Test tubes: a) cylindrical with Fig. 1.5. Volumetric utensils: 1) beaker, unfolded edge, b) cylindrical 2) cylinder, 3) volumetric flask, without bend, c) sharp-bottomed (centrifuge - 4) graduated pipettes, naya), d) with interchangeable conical - 5) Mora pipette, 6) pipette with thin sections, e) with a conical section and with a piston, 7) burette with outlet tube
For rough measurement of liquids, beakers are used - conical glasses expanding upwards with marked divisions and measuring cylinders. To measure large fixed volumes of liquids, volumetric flasks are used, their capacity ranges from 10 ml to 2 liters, and for accurate measuring of small volumes of liquids - pipettes and burettes - pipettes with a tap.
There are two types of pipettes: 1) "for filling" - the zero mark at the top and 2) "for pouring" - the upper mark indicates the maximum volume. For filling pipettes use rubber balloons, medical pears. Under no circumstances should organic liquids be sucked into the pipette by mouth!
Glass laboratory equipment also includes connecting elements, funnels, droppers, alcohol lamps, water jet pumps, desiccators, refrigerators, dephlegmators.
The connecting elements (Fig. 1.6) are designed for assembly on thin sections of various laboratory installations.
Rice. 1.6. The most important connecting elements: a) transitions, b) allongs, c) nozzles, d) connecting tubes, e) gates
Funnels (fig. 1.7) are used for pouring, filtering and separating liquids.
Rice. 1.7. Funnels: a) laboratory, b) filtering with sealed glass filter,
c) dividing, d) drip with a side tube for pressure equalization
Laboratory funnels are used for pouring liquids into narrow-necked vessels and for filtering solutions through a paper pleated filter. Funnels with glass filters are usually used to filter liquids that destroy paper filters. Separating funnels are designed to separate immiscible liquids during extraction and purification of substances. Dropping funnels are used for the controlled addition of liquid reagents during the synthesis, they are similar to separating funnels, they usually have a longer tube outlet, and the stopcock is located under the tank itself, their maximum capacity does not exceed 0.5 l.
Desiccators (Fig. 1.8) are used for drying substances under vacuum and for storing hygroscopic substances.
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Rice. 1.8. Desiccators: a) vacuum desiccator, b) conventional
Cups or glasses with substances to be dried are placed in the cells of porcelain liners, and a substance is placed on the bottom of the desiccator - a moisture absorber.
Refrigerators (Fig. 1.9) are used for cooling and condensing vapors. Air coolers used for boiling and distillation of high-boiling (tboil>1600C) liquids, ambient air serves as a cooling agent. Water-cooled refrigerators differ from air-cooled refrigerators by the presence of a water jacket (the cooling agent is water). Water cooling is used to thicken vapors and distill substances with a boiling point <1600C, and in the range of 120-1600C, stagnant water serves as a cooling agent, and below 1200C - running water. The Liebig refrigerator is used for the distillation of liquids, ball and spiral refrigerators are most applicable as reverse liquids for boiling liquids, since they have a large cooling surface.
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Rice. 1.9. Refrigerators and dephlegmator: a) air, b) with a straight tube (Liebig), c) ball, d) spiral, e) Dimroth, f) dephlegmator
Dephlegmators serve for more thorough separation of the fractions of the mixture during its fractional (fractional) distillation.
In laboratory practice, for work related to heating, porcelain dishes are used (Fig. 1.10).
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Rice. 1.10. Porcelain dishes: a) evaporating cup, b) Buchner funnel, c) crucible,
d) mortar and pestle, e) spoon, f) glass, g) burning boat, h) spatula
For filtering and washing precipitates under vacuum, porcelain suction filters - Buchner funnels are used. Mortars with pestles are designed for grinding and mixing solid and viscous substances.
To assemble and fix various devices in a chemical laboratory, tripods with sets of rings, holders (legs) and clamps are used (Fig. 1.11).
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Rice. 1.11. Laboratory stand (a) with a set of accessories: b) rings, c) clamps, d) holder
To fix the test tubes, racks made of stainless steel, aluminum alloys or plastics, as well as manual holders (Fig. 1.12), are used.
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Rice. 1.12. Stand (a) and manual holders for test tubes (b)
The tightness of the connection of the components of laboratory instruments is achieved using thin sections (Fig. 1.13) and rubber or plastic plugs. Stoppers are selected by numbers that are equal to the inner diameter of the closed neck of the vessel or the opening of the tube.
Rice. 1.13. Tapered sections: a) cores, b) coupling
The most universal and reliable way of sealing a laboratory instrument is to connect its individual parts with the help of conical sections by joining the outer surface of the core with the inner surface of the coupling.
I.3 BASIC OPERATIONS WHEN WORKING IN THE ORGANIC CHEMISTRY LABORATORY
Qualified performance of practical work by an experimental chemist is impossible without knowledge of the technique of carrying out basic operations. Therefore, it is necessary to study and master the most commonly used operations in the laboratory of organic chemistry: heating, cooling, dissolving, drying, grinding, mixing, etc. Their correct implementation is also necessary to ensure safe working conditions.
I.3.1 HEATING
One of the conditions for the flow of chemical reactions in a given direction is the strict observance of a certain temperature regime.
The main organic reactions are non-ionic and proceed slowly, therefore they are often carried out when heated, which contributes to an increase in the reaction rate - the reaction rate increases by 2-4 times when heated by 100C (van't Hoff rule).
For heating, various burners, electric heaters, water vapor, etc. are used. The choice of a heating device is carried out taking into account the properties of the solvent, the reactants and the temperature at which the reaction should be carried out.
Burners are gas or liquid (alcohol) (Fig. 1.14). For rapid heating to relatively high temperatures (? 5000C), Bunsen and Teklu gas burners are used. These burners are a metal tube fixed on a metal stand, in the lower part of which there are holes with devices for adjusting the air supply. An alcohol burner is a tank made of thick-walled glass, through the neck of which a thread wick or cotton swab is pulled. The neck is covered with a metal or ground glass cap.
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Fig.1.14. Burners: a) alcohol, b) Bunsen gas, c) Teklu gas
The most widely used electric heaters are mantle heaters, tiles, drying cabinets, muffle, crucible, shaft furnaces and baths. When used for heating electric stoves and burners, local overheating and partial decomposition of organic matter can occur. To increase the uniformity of heating above 1000C, asbestos nets are used, fiberglass electric heaters with interwoven electric spirals (Fig. 1.15). To avoid overheating of the reaction mixture, the flame of the burner should not go beyond the circle of asbestos on the grid.
When working with explosive, flammable substances (ether, acetone, benzene, etc.), various types of heating baths are used to prevent local overheating. The heat-conducting medium in the heating baths is air, sand, water, organic liquids, metals, molten salts, etc. When choosing a certain type of bath, take into account the properties of the reaction mixture, the temperature regime, which must be observed for a long time. The level of the substance to be heated in the vessel must correspond to the level of the bath coolant.
To slightly increase the uniformity of heating, air baths are used - a Babo funnel with a gas burner (Fig. 1.16). The maximum temperature reached when using an electrically heated air bath is 250°C.
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Rice. 1.15. Electric heating mantle Fig. 1.16. Funnel Babo
Sand baths, equipped with electric or gas burners, have a large thermal inertia; they allow maintaining temperatures up to 4000C. Dishes with substances are placed at a depth of 2-5 cm in pre-calcined from organic impurities, sifted sand.
If in the experiment it is necessary to maintain a temperature not exceeding 1000C, boiling water baths are used. The container with flammable substances is gradually immersed in a preheated water bath, eliminating sources of heat. Using a thermometer, control the temperature of the mixture and, if necessary, change the cooled water to hot. Water baths should not be used when conducting an experiment with metallic potassium or sodium. When distilling volatile, combustible substances (petroleum ether, diethyl ether, etc.), steam baths are used.
Oil baths have a relatively large thermal inertia and are used for heating in the range of 100-2500C. The maximum temperature reached depends on the type of coolant (glycerin - up to 2000C, paraffin - up to 2200C). It should be remembered that when water enters, heated oils foam and splash, so a filter paper cuff is put on the lower end of the reflux condenser. To prevent ignition of the coolant vapor during overheating, the bath is placed in a fume hood, covered with asbestos cardboard, or cold oil is added to the bath. In no case can not be extinguished with water, sand!
The temperature is measured with a thermometer placed in the bath at the level of the bottom of the reaction flask, the thermometer should not touch the flask, the bottom and the walls of the bath.
Metal baths are used for heating in the range of 200-4000C, a more intense temperature increase causes rapid oxidation of the metal surface. Low-melting alloys of Wood (Bi:Pb:Sn = 4:2:1) with tmelt = 710C, Rose (Bi:Pb:Sn = 9:1:1) with tmelt = 940C are used as a coolant. The thermometer and vessels are placed after melting and removed before the coolants solidify.
For long-term maintenance of temperature in a given interval, thermostats are used (Fig. 1.17).
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Rice. 1.17. Thermostats: a) ultrathermostat UT-15, b) microthermostat MT-0.3
It should be remembered that local overheating of liquids above their boiling point can lead to an explosion. To avoid this, long glass capillaries sealed on one side are immersed in a cold liquid with the open end down or small pieces of fired unglazed porcelain, brick, the so-called "boilers", are placed. When heated, they release small air bubbles, which provide mixing and promote uniform boiling. "Boilers" are used once, because when cooled, the liquid fills their pores.
I.3.2 COOLING
When carrying out many chemical works, sometimes it becomes necessary to cool the reaction mixture. This operation is used to accelerate crystallization, separate products with different solubility, etc. In exothermic reactions, the release of a significant amount of heat can lead to overheating of the reaction mixture, and, consequently, cause a low yield of the final product. In these cases, a decrease in temperature is necessary. The amount of heat dissipated and the required temperature determine the choice of coolant.
Water is a simple, cheap and heat-consuming agent. The reaction vessel is cooled under running water, or periodically immersed in cold water. circulating cold water used for cooling and condensing vapors in refrigerator jackets. When the vapor temperature rises above 1500C, water coolers should not be used, since glass may crack due to a sharp temperature drop.
Crushed ice is used for cooling down to 00C. A mixture consisting of ice and a small amount of water has a more effective cooling effect, since more contact is achieved with the walls of the flask or test tube. If the presence of water does not interfere with the reaction, it is convenient to maintain low temperature by adding ice cubes directly to the reaction mixture
The use of special mixtures (Table 1.1) with which cooling baths are filled makes it possible to reach temperatures close to 0°C and below.
Table 1.1.
Coolant mixtures
|
Mixture components |
Quantity ratio |
Minimum temperature, 0C |
|
|
H2O, Na2S2O3.5H2O |
|||
|
Ice (snow), CaCl2.6H2O |
|||
|
Ice (snow), Na2S2O3.5H2O |
|||
|
H2O, NH4Cl, NH4NO3 |
|||
|
Ice (snow), KCl |
|||
|
Ice (snow), NH4NO3 |
|||
|
Ice (snow), NaNO3 |
|||
|
Ice (snow), NaСl (technical) |
|||
|
H2O, NH4Cl, NH4NO3 |
|||
|
Ice (snow), KСl (technical) |
|||
|
Ice (snow), conc. Hcl (cooled to 00С) |
|||
|
Ice (snow), NaСl (technical) |
|||
|
Ice (snow), CaCl2.6H2O |
By adding solid carbon monoxide (IV) ("dry ice") to individual solvents (acetone, ether, etc.), the temperature is reduced below -700C.
If long-term cooling is required, refrigerators are used. In order to avoid corrosion of the metal upon contact with a mixture of aggressive vapors and condensed moisture, to prevent the explosion of vapors of organic solvents, the vessels in the refrigerator are tightly sealed.
I.3.3 GRINDING
Grinding is the destruction of solids with the formation of material particles. Grinding is used to perform many operations: in obtaining a homogeneous mass of solids, in extraction, taking an average sample, etc. One of the decisive factors determining the rate of a heterogeneous reaction is the surface area of the solid phase and the possibility of its contact with the liquid medium. Grinding increases the reactivity of the compounds.
The main characteristics of the grinding process are the change in dispersion and the degree of grinding.
The degree of grinding - the ratio of the average size of the pieces of the source material to the average particle size of the crushed material.
Depending on the purpose of grinding, crushing (obtaining a lumpy product of the required size) and grinding (increasing the dispersion of a solid material, giving the particles a certain shape) are distinguished. Depending on the size of the crushed product, coarse (300-100 mm), medium (100-25 mm), fine (25-1 mm) crushing and coarse (1000-500 microns), medium (500-100 microns), fine ( 100-40 microns), ultra-fine (less than 40 microns) grinding.
Solids are ground manually or mechanically. The choice of method and means of grinding is determined by the mechanical and chemical properties of the processed material, the required degree of dispersion. For direct chemical action, fine and ultra-fine grinding is desirable. Materials for extraction and steam distillation may be limited to coarse grinding.
Grinding is carried out in mortars (Fig. 1.18) made of various materials. Metal mortars are used to grind pieces or large crystals of substances. Substances less solid than phosphorus are ground in porcelain tools. For the manufacture of analytical samples, agate mortars are used, since the mineral has a high hardness, is a little abraded, and does not clog the ground substance. The size of the mortar is chosen in accordance with the amount of working material, which should not occupy more than 1/3 of its volume. Grinding is carried out with rotational movements, from time to time cleaning parts of the mortar and pestle with a spatula and collecting the substance to the center. Substances are best processed in small portions. If the material is smeared and sticky, before grinding it is mixed with silicon oxide (IV), broken glass, pumice.
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Rice. 1.18. Mortars: a) agate, b) for grinding dusty and toxic substances.
With dusty and toxic substances, they work in a fume hood, using special mortars with dust-proof devices or closing an ordinary mortar with polyethylene with a hole for a pestle.
Laboratories also use mechanical attritors, crushers, mills, and homogenizers to grind substances.
It should be remembered that the grinding of substances increases their chemical activity, so the possibility of an explosion is not excluded. For safety reasons, before processing large quantities of unknown substances, it is necessary to make sure on a small sample that the possibility of an explosion is excluded.
I.3.4 MIXING
Stirring is a method of obtaining homogeneous mixtures. This operation for solid bulk substances is defined by the term mixing, for liquid - mixing.
Mixing is done manually and mechanically. The operation is carried out using a mixing device or by shaking. Periodic shaking is used if the use of stirrers is difficult, if during the operation the addition of substances, cooling, heating are not carried out. With a significant release of gases and vapors, shaking is not used.
The state of aggregation of the mixed substances determines the choice of method and equipment for its implementation. When working with small amounts of solids and liquids in fast reactions, manual stirring in the beaker with a glass rod or shaking the vessel is sometimes sufficient. The flasks are rotated, holding by the throat, the closed vessels are repeatedly turned over. It should be remembered that in vessels with low-boiling liquids, pressure increases with stirring, so the plugs in them must be held.
Working with viscous liquids, with large quantities of substances or carrying out the reaction for a long time, mechanical stirring is used. The operation can be carried out by means of magnetic, vibrating stirrers, as well as stirrers rotating with an electric drive.
Under normal conditions (at atmospheric pressure, temperature environment, in the presence of air moisture) mixing is carried out in open wide-mouthed vessels, thick- or thin-walled glasses, titration flasks, wide-mouthed test tubes, in special flasks. This utensil allows you to simultaneously use stirrers, thermometers, dropping funnels, etc.
Mechanical mixing is effectively carried out using glass stirrers (Fig. 1.19), which are easily made from thick sticks or tubes with a diameter of 4-10 mm. They are given a different configuration depending on the shape, size of the vessel and the width of its neck.
Depending on the mixing method, different types mixers (Fig. 1.20).
More efficient flat, propeller, or helical agitators are placed in open, cylindrical, wide-mouthed vessels.
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Rice. 1.19. Glass stirrers Fig. 1.20. Agitators
For narrow-necked dishes, agitators with glass or fluoroplastic blades are used, which lean outward under the action of centrifugal forces. They are not suitable for intensive mixing. At high speeds, stirrers of this type can easily break and break the reaction vessels.
Propeller and centrifugal mixers are not suitable for heavy, solid substances (eg molten sodium). In these cases, it is convenient to use a Gershberg stirrer with a glass rod and wire blades (d=1-2 mm), which is easily inserted through the narrow neck of the reaction vessel. When working, its blades take on the shape of a flask, easily glide along the walls without leaving scratches. To work with substances that stick to the walls of narrow-necked flasks, scraper-type stirrers are used, but they cannot be used while simultaneously introducing a thermometer into the flask.
Mixing in large volumes is carried out using metal paddle and centrifugal mixers.
When working in a high vacuum and with small volumes of low-viscosity substances (during liquid-liquid extraction, electrolysis, titration), it is convenient to use magnetic stirrers (Fig. 1.21). They consist of a motor with a rotating magnet and a rod placed in a reaction vessel. Under the influence of the magnetic field created by the rotor of the electric motor, the rod begins to move. Magnetic stirrers can be combined with flat electric heaters, but the low stability of the magnets when heated must be taken into account. The advantages of this type of stirrers are the possibility of using the equipment without special training, placing the stirring rod in closed apparatus (sealed vessels).
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Fig.1.21. Magnetic stirrer
To mix liquids with gases, for immiscible liquids, vibrating mixers are installed, in which a membrane with a glass or steel plate is driven by an alternating electromagnetic field. This method is effective for the formation of thin emulsions.
When carrying out many reactions requiring stirring, it becomes necessary to prevent the leakage of volatile substances, maintain an increased or reduced pressure, and isolate the contents of the vessel from the external environment (the penetration of air and water vapor). Tightness is ensured by seals or special devices - gates, and the reliable operation of seals depends, in turn, on the supply of lubricating fluid (water, oil, glycerin, etc.)
To ensure uniform, silent operation of agitators, it is necessary to fix the position of their axis. The supports used for fastening must be sufficiently immobile, and the stirrer shaft must not oscillate during rotation.
Before starting work, scrolling the stirrer by hand, you need to make sure how easily it rotates, whether it touches the walls of the reactor, thermometer and other parts of the device.
Obtaining a homogeneous mass of solid bulk solid materials from individual substances by mixing them can be carried out simultaneously with chemical transformations, with grinding, heating, cooling, moistening. In industrial conditions, special devices of periodic and continuous action are used for this.
When mixing several solids, it is necessary that they have, as far as possible, the smallest possible particles of the same size.
Under laboratory conditions, crushed substances can be poured into the middle of a square sheet and mixed by rolling, lifting its ends alternately. Solids mix well when repeatedly sieved through sieves, the diameter of the holes of which exceeds the diameter of the working particles by 2-3 times. Mixing can also be carried out by repeatedly pouring substances from one vessel into another, while the containers are filled with mixed substances by no more than half the volume.
All devices intended for grinding (mortars, mills, etc.) can also be used for mixing.
I.3.5 DRYING
In organic chemistry, some reactions are possible only in the absence of moisture; therefore, preliminary drying of the starting materials is necessary. Drying is the process of releasing a substance, regardless of its state of aggregation, from an admixture of liquid. Drying can be carried out by physical and chemical methods.
The physical method consists in passing dry gas (air) through the substance to be dried, heating or keeping it in vacuum, cooling, etc. In the chemical method, drying reagents are used. The choice of drying method is determined by the nature of the substance, its state of aggregation, the amount of liquid impurities and the required degree of drying (Table 1.2). Drying is never absolute and depends on temperature and desiccant.
Gases are dried by passing them either through a layer of a water-absorbing liquid (usually concentrated sulfuric acid) poured into a Drexel wash bottle (Fig. 1.22), or through a layer of a granular desiccant placed in a special column or U-shaped tube. An effective method of drying air or gases is strong cooling. When a current is passed through a trap cooled by a mixture of acetone with dry ice or liquid nitrogen, water is frozen out, which is deposited on the surface of the trap.
Table 1.2.
The most common dehumidifiers and their applications
|
Dehumidifier |
Drainable substances |
Substances for which application is not allowed |
|
|
Neutral and acidic gases, acetylene, carbon disulfide, hydrocarbons and their halogen derivatives, acid solutions |
Bases, alcohols, ethers, hydrogen chloride, hydrogen fluoride |
||
|
Noble gases, hydrocarbons, ethers and esters, ketones, carbon tetrachloride, dimethyl sulfoxide, acetonitrile |
Acidic substances, alcohols, ammonia, nitro compounds |
||
|
CaO (soda lime) |
Neutral and basic gases, amines, alcohols, ethers |
||
|
Ethers, hydrocarbons, tertiary amines |
Chlorine derivatives of hydrocarbons, alcohols and substances that react with sodium |
||
|
Neutral and acidic gases |
Unsaturated compounds, alcohols, ketones, bases, hydrogen sulfide, hydrogen iodide |
||
|
Ammonia, amines, ethers, hydrocarbons |
Aldehydes, ketones, acidic substances |
||
|
anhydrous K2CO3 |
Acetone, amines |
Substances of an acidic nature |
|
|
Paraffinic hydrocarbons, olefins, acetone, ethers, neutral gases, hydrogen chloride |
Alcohols, ammonia, amines |
||
|
anhydrous Na2SO4, MgSO4 |
Esters, solutions of substances sensitive to various influences |
Alcohols, ammonia, aldehydes, ketones |
|
|
silica gel |
Various substances |
Hydrogen fluoride |
Rice. 1.22. Gas drying: 1) Drexel flask, 2) column with solid desiccant, 3) U-tube, 4) cold traps: a) cooling liquid, b) Dewar vessel
The drying of liquids is usually carried out by means of direct contact with one or another desiccant. The solid desiccant is placed in a flask containing the organic liquid to be dried. It should be noted that the use of too much desiccant can lead to the loss of the substance as a result of its sorption.
Drying of solids is carried out in the simplest way, which consists in the following: the substance to be dried is placed in a thin layer on a sheet of clean filter paper and left at room temperature. Drying is accelerated if it is carried out with heat, for example in an oven. Small amounts of solids are dried in conventional or vacuum desiccators, which are thick-walled vessels with ground-in grinding lids. The polished surfaces of the lid and the desiccator itself must be lubricated. The desiccant is located at the bottom of the desiccator, and the substances to be dried in bottles or Petri dishes are placed on porcelain partitions. The vacuum desiccator differs from the usual one in that its lid has a tap for connecting to a vacuum. Desiccators are used only for operation at room temperature, they must not be heated.
I.4 METHODS OF ISOLATION AND PURIFICATION OF SUBSTANCES
I.4.1 FILTERING
The simplest way to separate the liquid from the solid particles in it is decantation - draining the liquid from the settled sediment. However, it is difficult to separate completely the liquid phase from the solid in this way. This can be achieved by filtration - passing liquid with sediment through the filter material. There are various filter materials and various filtering methods.
The most common filter material in the laboratory is filter paper. It is used to make paper filters. The size of the filter is determined by the mass of the sediment, not by the volume of liquid being filtered. The filtered precipitate should occupy no more than half of the filter volume. Before starting work, the filter is moistened with the solvent to be filtered. During filtering, the liquid level should be slightly below the top edge of the filter paper.
A simple filter is made from a square piece of filter paper (Fig. 1.23.) The filter should fit snugly against the inner surface of the glass funnel. The folded filter has a large filtering surface, filtration through it is faster. If the solution contains strong acids or other organic substances that destroy paper, glass crucibles with a porous glass bottom or glass funnels with porous glass plates sealed into them are used for filtration. Glass filters have a number according to the pore size: the larger the filter number, the smaller the pore cross section and the finer deposits can be filtered on it.
Several filtration methods are used in the laboratory: simple, vacuum, hot.
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Rice. 1.23. Filters: Fig. 1.24. Simple filtering
1) making a simple filter, 2) making a folded filter, 3) a filter crucible with a porous plate, 4) funnels with a glass porous plate
Simple filtration is reduced to the use of a glass funnel with a paper filter embedded in it (Fig. 1.24). The funnel is inserted into the ring, a glass or a flat-bottomed flask is placed under it to collect the filtered liquid (filtrate). The tip of the funnel should be slightly lowered into the receiver and touch its wall. The liquid to be filtered is transferred to the filter over a glass rod.
To speed up and more completely separate the precipitate from the filtrate, vacuum filtration is used. A Buchner porcelain funnel (Fig. 1.25), which has a flat perforated septum, is inserted into a flat-bottomed thick-walled Bunsen flask with a rubber stopper, on which a paper filter is placed. The filter is cut to fit the bottom of the funnel. The vacuum is created by a water jet pump. If the pressure in the water supply is reduced, water from the pump may enter the appliance. To avoid this, a safety bottle is installed.
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Rice. 1.25. Filtration a) in vacuum: 1) Bunsen flask, 2) Buchner funnel; b) small amounts of substances
When filtering in vacuum, certain rules must be observed: 1) connecting a water jet pump and connecting it to the system, 2) wetting the filter with a small amount of the solvent that is supposed to be filtered, 3) adding filter fluid. The precipitate collected on the filter is squeezed out with a glass stopper until the mother liquor stops dripping from the funnel. If a whistling sound occurs during filtering, this indicates a loose or broken filter, in which case the filter should be replaced. If the precipitate on the Buchner funnel needs to be washed out, then using three-way valve first connect the Bunsen flask to the atmosphere, then the precipitate is soaked in washing liquid and filtered, reconnecting the vacuum. After filtration is completed, the entire system is first disconnected from the vacuum, then the water jet pump is turned off.
Hot solutions tend to filter faster than cold solutions because the heated liquid has a lower viscosity. Hot filtration is carried out in glass funnels heated from the outside in one way or another (Fig. 1.26). The simplest method, most applicable for filtering aqueous solutions, is to use a funnel with a short tail, which is placed in a beaker without a spout with a diameter slightly smaller than the top edge of the funnel. A little water is poured into the bottom of the glass, and the funnel is closed with a watch glass. Bring water in a glass to a boil. When the water vapor heats the funnel, the watch glass is removed and the hot filtered mixture is poured into the funnel. During the entire filtration process, the solution in the beaker is maintained at a gentle boil.
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Rice. 1.26. Funnels for 1) hot filtration: a) with steam heating, b) with hot water heating, c) with electric heating; 2) Cooling filtering
I.4.2 CRYSTALLIZATION
Crystallization is one of the most important methods for the purification and isolation of solids in laboratory and industrial settings. The method is based on the process of crystal formation from a melt, solution or gas phase. But the substance obtained as a result of crystallization is not always sufficiently pure, therefore the resulting product is subjected to further purification, which is called recrystallization. The contaminated substance, when heated, is dissolved in a suitable solvent and a saturated solution is obtained. The hot solution is filtered to remove insoluble impurities, then the filtrate is cooled. When a saturated solution is cooled, the solubility of substances decreases. Part of the solute precipitates as a precipitate, which contains fewer impurities than the original substance. The method is applicable to substances whose solubility increases significantly with increasing temperature.
The result of crystallization depends to a greater extent on the choice of solvent (tab. 1.3). The substance to be purified should be poorly soluble in the chosen solvent in the cold and well - at its boiling point. Contaminants should be difficult to dissolve or be insoluble in a given solvent. The solvent must not react with the solute. It should cause the formation of stable crystals and be easily removed from the crystal surface upon washing and drying.
Table 1.3.
Solvents used in recrystallization
When the solvent is selected, the substance is heated with it to a boil, observing all precautions. First, the solvent is taken in a smaller amount than is necessary for the complete dissolution of the substance, and then it is added through a reflux condenser in small portions (Fig. 1.27).
Rice. 1.27. Crystallization device:
1) flask, 2) reflux condenser, 3) bath, 4) boilers
If necessary, the solution is decolorized by adding an adsorbent (crushed activated carbon, finely torn filter paper). Before adding adsorbents, the solution should be cooled slightly, as these substances can enhance the boiling process, which will lead to vigorous ejection from the flask. The solute-adsorbent mixture is reheated to boiling and filtered while hot using a conical funnel and a pleated filter. The flask with the filtrate is left to cool. Gradually, crystals of the test substance fall out of the filtrate. Slow cooling of the filtrate makes it possible to obtain large crystals, while fast cooling produces small ones.
Solid organic substances can be separated as oily liquids during the distillation of solvents, which makes it difficult to crystallize them. This can be avoided by introducing a few pure crystals of the crystallizable substance. Rubbing the glass rod against the walls of the vessel also facilitates the crystallization process.
WORKSHOP
Experience 1. RECRYSTALLIZATION OF BENZOIC ACID
Reactants: benzoic acid, water
1 g of benzoic acid and 50 ml of water are placed in a 100 ml conical flask. The mixture is heated to a boil - benzoic acid is completely dissolved. The hot solution is quickly filtered through a pleated filter and the filtrate is equally poured into two flasks. The contents of one flask are rapidly cooled under running tap water or in ice and shaken. Benzoic acid precipitates in the form of small crystals.
The solution in another flask is kept at room temperature for 20-25 minutes. Slow crystallization occurs and shiny large lamellar crystals of benzoic acid are formed. The resulting crystals are filtered off and dried. T.pl.=1220С.
Experience 2. RECRYSTALLIZATION OF ACETANILIDE
IN ALCOHOL SOLUTION
Reactants: acetanilide, ethyl alcohol
1 g of acetanilide and 5 ml of ethyl alcohol are placed in a flask. The contents of the flask, constantly shaking, are heated in a hot water bath until the mixture begins to boil, achieving complete dissolution of acetanilide. Half of the resulting alcohol solution is poured into a test tube and cooled. To the rest of the hot solution, with shaking, add warm water(12-15 ml) until a slight turbidity appears, after which the solution is slightly heated until clear and allowed to cool. When the alcoholic solution is cooled, no precipitate of acetanilide is formed, while crystals separate from the aqueous-alcoholic solution with gentle shaking.
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The boundary between organic and inorganic substances. Synthesis of substances previously produced only by living organisms. The study of the chemistry of organic substances. Ideas of atomism. The essence of the theory of chemical structure. The doctrine of the electronic structure of atoms.
abstract, added 09/27/2008
Study of the theory of chemical structure of A.M. Butlerov. Characterization of the isomerism of organic substances. Features of carbon-carbon bonds. Electronic structure conjugated dienes. Methods for obtaining arenes. Classification of carbonyl compounds.
course of lectures, added 09/11/2017
Adamantane is the ancestor of the homologous series of the family of hydrocarbons with a diamond-like structure, diamantane, triamantane. The emergence and development on the basis of the chemistry of adamantane is one of the areas of modern organic chemistry - the chemistry of organic polyhedrans.
term paper, added 10/08/2008
Consideration of reactions based on the formation of complex compounds of metals and without their participation. The concept of functional-analytical and analytic-active groups. The use of organic compounds as indicators of titrimetric methods.
term paper, added 04/01/2010
Chemical bond in organic molecules. Classification of chemical reactions. Acid and basic properties of organic compounds. Heterofunctional derivatives of the benzene series. Carbohydrates, nucleic acids, lipids. heterocyclic compounds.
tutorial, added 11/29/2011
Oxidative dimerization of methane. Mechanism of catalytic activation of methane. Production of organic compounds by oxidative methylation. Oxidative transformations of organic compounds containing a methyl group in the presence of a catalyst.
dissertation, added 10/11/2013
The subject of organic chemistry. The concept of chemical reactions. Nomenclature of organic compounds. Characteristics and methods of obtaining alkanes. Covalent chemical bonds in the methane molecule. Chemical properties of haloalkanes. Structural isomerism of alkenes.
test, added 07/01/2013
Classification of organic compounds according to the carbon skeleton and functional groups. The relationship of the chemical structure of organic molecules with their reaction center. Influence of the electron-spatial structure on the mechanisms of chemical transformations.
Foreword
PART I WORKING TECHNIQUES FOR ORGANIC SYNTHESIS
Chapter I. Organization of work and safety
1. General rules for working in the laboratory of organic synthesis
2. Precautions and first aid in case of accidents
Working with poisonous and caustic substances
Work with flammable and explosive substances
Glass handling rules
First aid for burns, poisoning and other accidents
Putting out local fires and burning clothes
3. Basic laboratory chemical glassware
4. Assembly of devices
5. Washing and drying chemical glassware
6. Use of literature and rules for compiling a report
Chapter II. Basic operations when working in a chemical laboratory
1. heating
2. Cooling
3. Temperature measurement and control
4. Grinding and mixing
5. Dissolution and properties of some organic solution gels
Ethanol
Methyl alcohol
Diatyl ether
Petroleum ether
Acetone
6. Drying and main dryers
Dehumidification of gases
Drying of organic liquids
Drying solids
Basic dryers
7. Filtering
Filtration at normal pressure
Vacuum filtration
Chapter III. Methods for purification of organic substances
1. Crystallization
Solvent choice
Carrying out recrystallization
Separation of crystals
2. Sublimation (sublimation)
3. Extraction
4. Distillation
Simple distillation at atmospheric pressure
Steam distillation
Distillation under reduced pressure
Fractional (fractional) distillation
Rectification
5. Chromatography
Adsorption chromatography
Partition chromatography
Chromatography on paper
Ion exchange chromatography
Chapter IV. Determination of the most important constants of organic compounds
1. Melting point
2. Boiling point
3. Relative density
4. Refractive index
5. Molecular weight
Chapter V. Work with compressed and liquefied gases
1. Gas cylinders and handling
2. Gas dosing
3. Purification and introduction of gases into the instrument
4. Safety regulations for working with gas cylinders
Chapter VI. Quantitative elemental analysis of organic substances
1. Determination of carbon and hydrogen by semi-micro method
Installation assembly
Performing analysis
2. Determination of nitrogen by a semi-micro method (according to Dumas)
Installation assembly
Performing analysis
3. Determination of carbon and hydrogen by the micromethod
Installation assembly
Performing analysis
PART II SYNTHESIS OF ORGANIC SUBSTANCES
Chapter VII. halogenation reactions
1. Substitution of the hydroxyl group of alcohol with a halogen
2. Substitution of the hydroxyl group of acids with a halogen
3. Addition of a halogen via a multiple bond
4. Direct replacement of hydrogen by halogen
5. Examples of syntheses
Ethyl bromide
(?) - Bromonaphthalene and ethyl bromide
Ethyl iodide
Butyl bromide
Acetyl chloride
benzoyl chloride
1,2-dibromoethane
Bromobenzene
(?)-Bromonaphthalene
(?)-Bromanisole
Chapter VIII. Alkylation reactions
1. Alkylation of aromatic hydrocarbons with alcohols in the presence of sulfuric acid
2. Obtaining ethers
3. Examples of syntheses
sec-Butylbenzene
dibutyl ether
Isoamyl ether
diphenyl ether
Fenetol
Ethyl ether (?) -naphthol (new nerolin, bromeliad)
Anizol
Chapter IX. Acylation reactions
1. Acylation of alcohols and amines with carboxylic acids
2. Acylation of alcohols, phenols and amines with acid chlorides
3. Acylation of alcohols, phenols and amines with acid anhydrides
4. Examples of syntheses
Acetic ethyl ether
Acetic isoamyl ether
Ethyl ester of chloroacetic acid
Diethyl ester of oxalic acid
Ethyl ester of benzoic acid
benzanilide
Aspirin (acetylsalicylic acid)
(?)-Naphthyl acetate
Acetanilide
Chapter X. Friedel-Crafts Reactions
1. Alkylation of aromatic compounds
2. Acylation of aromatic compounds
3. Examples of syntheses
Isopropylbenzene
Diphenylmethane
Acetophenone
Benzophenone
Chapter XI. Oxidation reactions
1. Double bond oxidation
2. Oxidation of primary and secondary alcohols to aldehydes or ketones
3. Oxidation of aldehydes and ketones to acids
4. Oxidation of methyl and methylene groups
5. Obtaining quinones by oxidation
6. Examples of syntheses
Acetaldehyde
propionaldehyde
Isovaleric aldehyde
Benzophenone
isobutyric acid
Valeric acid
Benzoic acid
Benzoquinone
Anthraquinone
Chapter XII. Nitration reactions
1. Nitration of fatty hydrocarbons
2. Nitration of aromatic hydrocarbons
3. Examples of syntheses
Nitromethane
Nitrobenzene
(?)- and (?)-Nitrotoluene
(?)- and (?)-Nitrophenol
(?)-Nitronaphthalene
Chapter XIII. Amination reactions
1. Preparation of fatty amines
2. Preparation of aromatic amines
3. Examples of syntheses
methylamine
Aniline
(?)- and (?)-Toluidine
(?)-Naphthylamine
Chapter XIV. Sulfonation reactions
1. Sulfonation of aromatic compounds
2. Examples of syntheses
(?)-Naphthalenesulfonic acid (sodium salt)
Benzenesulfonic acid (sodium salt)
(?)-Toluenesulfonic acid
Sulfanilic acid
Chapter XV. Diazotization and azo coupling reactions
1. Reactions of diazonium salts, accompanied by the release of nitrogen
2. Reactions of diazonium salts without nitrogen evolution
3. Examples of syntheses
Phenol
Iodobenzene
Helianthin
(?)-Naphthol-orange
Chapter XVI. Grignard reactions
1. Getting hydrocarbons
Quantitative determination of active hydrogen according to Chugaev-Tserevitinov
2. Obtaining carboxylic acids
3. Obtaining alcohols
4. Examples of syntheses
Phenylacetic acid
Triphenylcarbinol
Diphenylcarbinol (benzhydrol)
Chapter XVII. Cannzzaro reaction
Synthesis of benzoic acid and benzyl alcohol
Chapter XVIII. Claisen reaction
Synthesis examples
Acetoacetic ester
Benzoidacetor
Chapter XIX. Polymerization and polycondensation reactions
1. Polymerization
2. Polycondensation
3. Examples of syntheses
Paraldehyde
Polystyrene
Polymethyl methacrylate
Copolymer of styrene with methyl methacrylate
Methyl Methacrylate (from Polymethyl Methacrylate)
Glyphthalic resin
Phenolic-formaldehyde resin
Chapter XX. Identification
1. Preliminary tests
2. Qualitative reactions
3. Derivation
Recommended reading
Applications
1. Dryers for organic compounds
2. Water vapor pressure at different temperatures
3. Pressure of liquefied gases in cylinders
4. Color of compressed gas cylinders
5. Density of sulfuric acid solutions (20°С)
6. Density of hydrochloric acid solutions (20°С)
7. Density of nitric acid solutions (20°С)
8. Density of caustic soda solutions (20°C)
9. Density of solutions of caustic potash (20°C)
10. Physical properties alcohols and their derivatives
11. Physical properties of phenols and their derivatives
12. Physical properties of aldehydes and their derivatives
13. Physical properties of ketones and their derivatives
14. Physical properties of carboxylic acids and their derivatives
15. Physical properties of primary and secondary amines and their derivatives
16. Physical properties of alkyl halides and their derivatives
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