Name of the Experiment: Preparation at benzoic acid from Benzaldehyde
Yield - 20 mg
M..-120° C.
Theory: When benzaldehyde (CH, CHO) is react with a concentrated solution of strong base (NaOH or KOH), Benzyl Benzate is formed which on hydrolysis gives benzyl alcohol and salt of Benzoic acid, after acidification. It gives benzoic acid. This reaction is called cannizzaro's reaction.
Chemicals required: 1.Benzaldehyde-30 ml
Chemicals required: 1.Benzaldehyde-30 ml
2. NaOH-20 g
Procedure: 20 g of NaOH or KOH was added into 25 ml of ice cold water in instalments. The solution was cooled and 30 ml of benzaldehyde was added to it. The bottle was corked and shaken vigorously. The semi solid mass as left for few hours and water was added. The contents were poured into a separating layer and benzoyl alcohol was extracted with ether. The aqueous layer was treated with excess of conc HCI. The mixture was cooled and filtered. The benzoic acid was throughly washed with cold water and crystallised from boiling water.
Procedure: 20 g of NaOH or KOH was added into 25 ml of ice cold water in instalments. The solution was cooled and 30 ml of benzaldehyde was added to it. The bottle was corked and shaken vigorously. The semi solid mass as left for few hours and water was added. The contents were poured into a separating layer and benzoyl alcohol was extracted with ether. The aqueous layer was treated with excess of conc HCI. The mixture was cooled and filtered. The benzoic acid was throughly washed with cold water and crystallised from boiling water.
Yield - 20 mg
M..-120° C.
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