Objective: To prepare Phenyl benzoate from Phenol.

Apparatus/Glassware Required: 250 mL conical flask, beaker, volumetric flask, measuring cylinder, suction pump, Buchner funnel, filter papers etc.

Chemicals Required: Phenol, Benzoyl chloride, sodium hydroxide, alcohol

Principle: Phenols react with an aromatic acid chloride in the presence of excess of NaOH at room temperature to form an ester. The reaction is called Schotten Baumann reaction. If phenol is shaken with benzoyl chloride and excess amount of sodium hydroxide solution, it is benzoylated to give the ester, phenyl benzoate. The phenol is first converted into the ionic compound sodium phenoxide (sodium phenate) by dissolving it in sodium hydroxide solution. The phenoxide ion reacts more rapidly with benzoyl chloride than the original phenol does, but even so you have to shake it with benzoyl chloride for about 15 minutes. Solid phenyl benzoate is formed.

For Chemical Reaction (click download tab)

Procedure:

1. In a 100 mL conical flask dissolve 2.5 g of phenol in 35 mL of 10% sodium hydroxide solution and then add 5 mL benzoyl chloride to it.
2. Cork the flask properly and shake the mixture vigorously until the smell of benzoyl chloride has disappeared.
3. The phenyl benzoate which separates is filtered off, washed with cold water, dried, and recrystallized from alcohol.

Uses:

1. It can be used in a variety of polyesters, which have applications in products from clothing to heavy industry.
2. It is considered an excellent starting material for the production of optical components, particularly high quality lenses for still and motion picture cameras.

Note: Colourless crystals; insoluble in water; M.P. 68° C

Precautions:

1. Benzoyl chloride is lachrymatory and should be handled with care under a FUME HOOD.
2. Phenol is not only toxic but will cause severe burns.