ORGANIC CHEMISTRY PRACTICAL

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1 Ex. No. ORGANIC CHEMISTRY PRACTICAL Course Code: PSCH 103: One step preparations Aim of experiment Date Sign of Prof. 1. Preparation of m-dinitrobenzene from nitrobenzene 2. Preparation of 5-nitrosalicylic acid from salicylic acid 3. Preparation of 4-bromonitrobenzene from bromobenzene 4. Preparation of 4-nitroacetanilide from acetanilide 5. Preparation of benzoic acid from benzaldehyde 6. Preparation of 9,10-anthraquinone from anthracene 7. Preparation of p-nitrobenzoic acid from p-nitrotoluene 8. Preparation of benzil from benzoin 9. Preparation of anthracene-maleic anhydride from anthracene and maleic anhydride (Diels Alder reaction) 10. Preparation of dibenzylideneacetone from acetone and benzaldehyde (Aldol condensation) 11. Preparation of 1,2,4-triacetoxybenzene from p- benzoquinone 12. Preparation of p-bromoacetanilde from acetanilide. 13. Preparation of 5,5-diphenyl hydantoin from benzil and urea 14. Preparation of 3-methyl-1-phenylpyrazol-5-one from ethyl acetoacetate 15. Preparation of 2-methylbenzimidazole from o- phenylenediamine 16 Preparation of 2,3-diphenylquinoxaline from o- phenylenediamine. In-charge

2 A. LABORATORY'S RULES 1. Practicians must wear laboratory uniform in every laboratory activities including during the discussion time. 2. Practicians must prepare the journal, report, and other tasks before practice begin. 3. Practicians not allowed eating, drinking and smoking in laboratory. 4. Practicians not allowed entering assistant room, storage and the research laboratory without permission from the assistant. 5. Except journal and laboratory kit, other should not be placed on the practice table. 6. Practice is done in definite workday and practicians not allowed working outside these days without pennission from the assistant. 7. Practicians should pay attention to sign (bell sound) at the beginning and at the end of practice time. 8. The fill up of attendance list will be done every workday including in every laboratory activities. 9. Practicians not allowed to left the laboratory during the work hour without permission from the assistant. Leaving more than 15 minutes should be with written permission. 10. During the experiment activities, all windows should be opened. 11. Practicians that have finished the practice should asked for the signature of assistant. 12. Practicians not allowed to take chemistry compound from storage, the assistant will prepare the chemistry compounds. Every chemistry compound bottle should be clean and dry. 13. Liquid reagents test must be applied by pipette 14. Solid reagents test must be applied by spatula. 15. Reagents should be placed on reagents table and not allowed to remove. 16. Every tool should be used according to its utility. 17. Laboratory kit contains boiling chips, pipette, spatula, vial, matches, and stirring stick. 18. Cleanness kit contains napkin, tube brush and detergent. 19. Each tool must be clean and dry before the storage. 20. Practicians not allowed keeping chemical compounds in the drawer except with the pemlission from assistant.

3 21. Before leaving the laboratory, fume hood, weight room, laboratory floor, washing stand, table and seat should be clean and neat. Water, gas, electricity and windows should be shut down. 22. Journal contents are experiment's number, procedure, chemical and physical properties of matter that used in the experiment, mechanism reaction, chemical and physical properties of the reaction, theory, reference, observations and observation tables, and table of result. 23. Report and tasks must be wrote on A4 paper and covered. Cover contents are practician code, experiment's number, name, date of experiment, name of the assistant. 24. Each journal must have agreement from assistant otherwise practician not allowed to do the experiment. 25. Journal, report and tasks should be handed over before the experiment begins. Practician who don't hand over the journal, report and tasks on time won't be allowed to do the experiment. 26. Report and tasks that have been handed over can't be taking back by practicians. 27. In everything related with Chemistry Laboratory practicians are not allowed to cheat. Any violation related to this rule, will caused restitution of practician back to his/her own department and will not allowed to practice for 1 or 2 semester, or the case will be handle by university. 28. Repeated warning that caused by repeated violation will affected to practice point. 29. Practician must obey the rules without any exception. NOTES: a. Practicians can have final exam after completed all experiment, report, and tasks, collect all journals and finished all problems of tools and tables. b. Each tool that returns to laboratory should be in good and clean condition. c. Tables should be returned in clean and neat condition. And so as the laboratory. d. Anything related to the laboratory's rules that have not been written will be arranged later.

4 Preparation of m-dinitrobenzene from nitrobenzene. Chemicals: conc. Sulphuric acid, sodium nitrate, nitrobenzene, distilled water, ethanol, acetone, ethyl acetate, pet ether, etc. 1. Place 5 ml of sulfuric acid and 4.5 g of sodium nitrate in a dry 100 ml conical flask. 2. Add 1.0 ml nitrobenzene in small portions with constant stirring. 3. Keep the funnel in flask and heat the reaction mixture with frequent shaking on a boiling water bath for about 30 minutes. 4. Cool the reaction mixture and pour into 40 ml ice cold distilled water with stirring. 5. Filter the crude product by using suction pump and wash with 2-3 times with cold distilled water. 6. Dry the crude product and record its yield. 7. Recrystalize the product by using ethanol, determine its m.p. and perform TLC in suitable mobile phase.

5 Preparation of 5-nitrosalicylic acid from salicylic acid Chemicals: Nitric acid, salicylic acid, distilled water, acetone, ethyl acetate, pet ether, etc. 1. Take 2 g of salicylic acid in 250 ml conical flask and add small amount of hot distilled water in it. 2. Add slowly 5 ml conc. Nitric acid with constant shaking of the flask. 3. Heat the flask on boiling water bath for about 5 minutes till no more brown fumes comes out form the reaction mixture. 4. Cool the content and pour into 50 ml ice cold distilled water with constant stirring. 5. Filter the crude product by using suction pump and wash with 2-3 times with cold distilled water. Dry the crude product and record its yield. 6. Recrystalize the product by using hot distilled water, determine its m.p. and perform TLC in suitable mobile phase.

6 Preparation of 4-bromonitrobenzene from bromobenzene Chemicals: Nitric acid, sulphuric acid, bromobenzene, distilled water, ethanol, acetone, ethyl acetate, pet ether, etc. 1. Take 2 ml of conc. Sulfuric acid and 2 ml conc. nitric acid in a 250 ml conical flask. 2. To this solution, add 1.0 ml of bromobenzene slowly with vigorous stirring during time 45 minutes. 3. Keep the funnel on the flask and heat it on a boiling water bath for 30 minutes. 4. Cool the reaction mixture and pour slowly into 20 ml ice cold distilled water with constant stirring. 5. Filter the crude product by using suction pump and wash with 2-3 times with cold distilled water. Dry the crude product and record its yield. 7. Recrystalize the product by using hot distilled water, determine its m.p. and perform TLC in suitable mobile phase.

7 Preparation of 4-nitroacetanilide from acetanilide Chemicals: Nitric acid, sulphuric acid, acetanilide, glycial acetic acid, distilled water, ethanol, acetone, ethyl acetate, pet ether, etc. 1. Take 5 g of actanilide in a dry 250 ml beaker and add 3 ml glycial acetic acid in it, stir well to get clear solution. 2. Add 5 ml of conc. Sulfuric acid with vigorous stirring and cool the reaction content into ice salt mixture. 3. Add drop wise precooled mixture of 1.5 ml of conc. Nitric acid and 1.0 ml of conc. Sulfuric acid with vigorous stirring, taking care that temperature does not rise above 10 0 C. 4. After addition of nitrating mixture, keep the reaction mixture at room temperature for 30 minutes. 5. Pour the reaction mixture into 100 ml of ice cold distilled water with stirring. 6. Filter the crude product by using suction pump and wash with 2-3 times with cold distilled water. Dry the crude product and record its yield. 7. Recrystalize the product by using ethanol, determine its m.p. and perform TLC in suitable mobile phase.

8 Preparation of benzoic acid from benzaldehyde. Chemicals: benzaldehyde, sodium carbonate, potassium permanganate, conc. HCl, distilled water, acetone, ethyl acetate, chloroform, etc. 1. Take 2 ml (2.088 g) of benzaldehyde in 250 ml dry conical flask. 2. Add 100 ml of distilled water and 3 g of sodium carbonate in it and stir. 3. Boil the reaction mixture and add slowly saturated solution of potassium permanganate solution till a pink color persists. 4. Heat the reaction mixture further on a sand bath for 30 minutes by using low flame. 5. Allow it to cool and filter to remove the solid impurity. 6. Acidify the filtrate with conc. HCl (add dropwise, check by using litmus paper). 7. Filter the crude product by using suction pump and wash with 2-3 times with cold distilled water. Dry the crude product and record its yield. 8. Recrystalize the product by using hot water, determine its m.p. and perform TLC in suitable mobile phase.

9 Preparation of 9,10-anthraquinone from anthracene. Chemicals: Anthracene, glycial acetic acid, chromium trioxide, sodium hydroxide, distilled water, acetone, ethyl acetate, pet ether, etc. 1. Place 1 g of anthracene and 10 ml glycial acetic acid in dry 100 ml round bottom flask fitted with a reflux condenser. 2. Heat the reaction mixture on boiling water bath till all anthracene get dissolve i.e. solution become clear and cool it to normal temperature. 3. In separate beaker, dissolve 2 g of chromium trioxide in 1.6 ml distilled water and add 5 ml of glycial acetic acid in it. 4. Add chromium trioxide solution in anthracene solution slowly with stirring and reflux the resultant solution for about 15 minutes. 5. Cool it and pour into 50 ml of cold distilled water with stirring. 6. Filter the crude product by using suction pump and wash with 2-3 times with cold distilled water and then 10 ml hot 1N sodium hydroxide solution and finally again with cold distilled water. Dry the crude product and record its yield. 7. Recrystalize the product by using glycial acetic acid or sublimize it, determine its m.p. and perform TLC in suitable mobile phase.

10 Preparation of p-nitrobenzoic acid from p-nitrotoluene. Chemicals: p-nitro toluene, Sodium dichromate dehydrate, conc. Sulphuric acid, etc. 1. Place 2.3 g of p-nitrotoluene, 6.65 g of sodium dichromate dehydrate and 15 ml of water in a 50 ml, two-necked round-bottomed flask. 2. Add 17 g (9.2 ml) of concentrated sulphuric acid dropping funnel during about 30 minutes to the well-stirred mixture. 3. The heat of dilution of the acid causes the p-nitrotoluene to melt and oxidation takes place; if the reaction shows signs of becoming vigorous, the rate of addition must be reduced. 4. When all the sulphuric acid has been introduced and the temperature of the mixture commences to fall, attach a reflux condenser to the flask, and reflux for half an hour. 5. Cool and pour the reaction mixture into ml of water. 6. Filter the crude p-nitrobenzoic acid at the pump and wash it with about ml of water.

11 Preparation of benzil from benzoin. Chemicals: Benzoin, conc. Nitric acid, ethanol, etc. A. By using fuming nitric acid: 1. Place 2.0 g of crude benzoin and 10 ml of fuming nitric acid in 50 ml round bottom flask fitted with air condenser. 2. Heat it on a boiling water bath (in the fume cupboard) with occasional shaking until the evaluation of oxides of nitrogen has caused (about 1.5 hours). 3. Cool the reaction mixture and pour into ml of cold water containing in beaker and stir until yellow solid product is obtained. 4. Filter the crude benzil at the pump and wash with water till it is free from nitric acid. 5. Recrystalize the product from ethanol or rectified spirit. Record the yield and m.p. of the product.

12 Preparation of anthracene-maleic anhydride from anthracene and maleic anhydride (Diels Alder reaction). Chemicals: Anthracene, maleic anhydride, xylene, activated carbon, acetone, ethyl acetate, pet ether, etc. 1. Place 1 g of anthracene (pure) and 0.55 g of maleic anhydride in 13 ml of dry xylene in dry round bottom flask fitted with a reflux condenser. 2. Reflux the reaction mixture in oil bath for 20 minutes (if possible, use assembly having mechanical stirrer arrangement). 3. Cool it and add 0.5 g of activated charcoal (to remove colored impurities) and boil it again for 5 minutes. 4. Filter the solution in hot condition and cool the filtrate to get solid product. 5. Filter the solid product by using suction pump and dry it in a vaccum desicator containing paraffin wax to absorb the traces of xylene. Record the yield and m.p. of the product.

13 Preparation of dibenzylideneacetone from acetone and benzaldehyde (Aldol condensation). Chemicals: Acetone, benzaldehyde, sodium hydroxide, distilled water, ethanol, acetone, ethyl acetate, pet ether, etc. 1. In a 250 ml conical flask, add a cold solution of 2.5 g of sodium hydroxide in 25 ml water and 20 ml ethanol, shake well till solution become clear. 2. Cool the aqueous alcoholic NaOH solution in water bath and add few drops of mixture of 2.55 ml (density g/ml) of pure benzaldehyde and ml of acetone slowly with vigorous stirring, a fluocculent precipitate forms in 2,3-minutes. Stir further at room temperature for 15 minutes. 3. After 15 minutes, add the remaining mixture of benzaldehyde-acetone mixture and continue the stirring for further 30 minutes. 4. Filter the solid product by using Buckner funnel and wash it with cold distilled water. Record the yield of the product. 5. Recrystallize the product by using hot ethyl acetate, record the m.p. and perform the TLC of compound in suitable mobile phase, record the R f value of reactant and products.

14 Preparation of 1,2,4-triacetoxybenzene from p-benzoquinone. Chemicals: Acetic anhydride, conc. Sulphuric acid, p-benzoquinone, cold distilled water, ethanol, acetone, ethyl acetate, pet ether, etc. 1. Take 3 g acetic anhydride and 1 drop of concentrated sulfuric acid in a dry 100 ml conical flask. 2. Add 1 g of p-benzoquinone to it slowly with continuous shaking of conical flask. The reaction is exothermic so that temperature of the reaction mixture rises to C and this temperature is maintained during the further addition (if necessary use water bath to control the temperature). 3. Allow the reaction mixture to cool about 25 0 C and pour into 15 ml of cold water with stirring. 4. Filter the product at the suction pump, dry it and record the yield of the product. 5. Recrystallize the product by using ethyl alcohol and determine its m.p. (97 0 C).

15 Preparation of p-bromoacetanilde from acetanilide. Chemicals: Acetanilide, Bromine, Acetic acid, Sodium metabisulfide, etc. 1. Dissolve 1.35 g of finely powdered acetanilide in 4.5 m1 of glacial acetic acid in a 50 m1 conical flask. 2. In another small flask dissolve 1.7 g (0.53 ml) of bromine in 2.5 m1 of glacial acetic acid. 3. Add the bromine solution slowly into above acetanilde solution with constant shaking to ensure thorough mixing: stand the flask in cold water. 4. Allow the final reaction mixture to stand at room temperature for 30 minutes with occasional shaking. 5. Pour the reaction product into 400 m1 of water; rinse the flask with about 100 m1 of water. Stir the mixture well and if it is appreciably coloured, add just sufficient sodium metabisulphite solution to remove the orange colour. 6. Filter the crystalline precipitate with suction on a Buchner funnel, wash thoroughly with cold water and press as dry as possible with a wide glass stopper. 7. Recrystallise from dilute methanol or ethanol (industrial spirit). Record the yield and m.p. of p-bromoacetanilide.

16 Preparation of 5,5-diphenyl hydantoin from benzil and urea. Chemicals: Benzil, urea, sodium hydroxide, hydrochloric acid, etc. 1. Place 0.53 g of benzil, 0.30 g of urea, 1.5 m1 of 30 per cent aqueous sodium hydroxide solution and 7.5 m1 of ethanol in a 25 m1 round-bottomed flask. Attach a reflux condenser and boil under reflux for at least 2 hours. 2. Cool it to room temperature, pour the reaction product into 12.5 m1 of water and mix thoroughly. 3. Allow to stand for 15 minutes and then filter under suction to remove an insoluble byproduct. 4. Render the filtrate strongly acidic with concentrated hydrochloric acid, cool in ice-water and immediately filter off the precipitated product under suction. 5. Recrystalize at least once from industrial spirit. Record the yield and m.p. of product. 6.

17 Preparation of 3-methyl-1-phenylpyrazol-5-one from ethyl acetoacetate. Chemicals: Ethyl acetoacetate, phenyl hydrazine, pet ether, alcohol, etc. 1. Mix together 0.50 g (0.49 ml) of redistilled ethyl acetoacetate and 0.40 g (0.365 ml) of phenylhydrazine (CAUTION in handling) in a large evaporating dish. 2. Heat the mixture on a boiling water bath in the fume cupboard for about 2 hours and stir from time to time with a glass rod. 3. Allow the heavy reddish syrup to cool somewhat (if solid is formed, grind it and then go for next step), add about 100 m1 of ether and stir the mixture vigorously for solidification. The syrup, which is insoluble in ether, will solidify within 15 minutes. 4. Filter the solid at the pump and wash it thoroughly with ether to remove coloured impurities. 5. Recrystallise it from hot water or from a mixture of equal volumes of ethanol and water. Record the yield and m.p. of 3-methyl-1-phenylpyrazol-5-one.

18 Preparation of 2-methylbenzimidazole from o-phenylenediamine. Chemicals: o-phenylenediamine dihydrochloride, acetic acid, alcohol, etc. 1. Heat together a mixture of g of o-phenylenediamine dihydrochloride, 4.0 ml of water and g of acetic acid under reflux for 45 minutes. 2. Cool the reaction mixture and immediately make basic by the gradual addition of concentrated ammonia solution. 3. Collect the precipitated product and recrystallise it from 10 per cent aqueous ethanol. 4. Record the yield and m.p. of product.

19 Preparation of 2,3-diphenylquinoxaline from o-phenylenediamine. Chemicals: o-phenylenediamine, benzil, rectified spirit, etc. 1. To a warm solution of 1.05 g of benzil in 4 m1 of rectified spirit add a solution of 0.55 g of o-phenylenediamine in 4 m1 of rectified spirit. 2. Warm in a water bath for 30 minutes, add water until a slight cloudiness persists and allow to cool. 3. Filter and recrystallise from aqueous ethanol to give 2,3-diphenylquinoxaline. 4. Record the yield and m.p. of the product.

20 INTERNAL EXAMINATION PRESENTATION AND PROJECT TOPICS Presentation experiment Preparation of 4-nitroacetanilide from acetanilide Preparation of benzoic acid from benzaldehyde Preparation of 9,10-anthraquinone from anthracene Preparation of p-nitrobenzoic acid from p-nitrotoluene Preparation of anthracene-maleic anhydride from anthracene and maleic anhydride (Diels Alder reaction) Preparation of dibenzylideneacetone from acetone and benzaldehyde (Aldol condensation) Preparation of p-bromoacetanilde from acetanilide. Preparation of 5,5-diphenyl hydantoin from benzil and urea Preparation of 3-methyl-1-phenylpyrazol-5-one from ethyl acetoacetate Preparation of 2-methylbenzimidazole from o-phenylenediamine Need of recrystallisation and TLC in organic preparations Importance of MSDS in chemical laboratory Name of the student Prajapati Suraj Sumaiya Shaikh Behera Alok Singh Priyanka Zirva Sanjay Hande Amit Shaikh Sabiha Magar Kishor Yogesh Velkar

Synthesis of Benzoic Acid

E x p e r i m e n t 5 Synthesis of Benzoic Acid Objectives To use the Grignard reagent in a water free environment. To react the Grignard reagent with dry ice, CO 2(s). To assess the purity of the product