To Prepare Benzoic Acid By Oxidation Of Benzaldehyde | Practical

APPARATUS REQUIRED:

1)conical flask

2) KMno4

3) Anhydrous Na₂Co₃

4) Bone charcoal etc.

5) Conc.H₂So₄

THEORY

Benzoic acid is prepared by the oxidation of benzaldehyde with the help of KMnO₄ in presence of alkali.

Benzoic acid is a compound with the chemical formula C7H6O2, commonly found in nature and used in various industrial applications.

PROCEDURE

5ml benzaldehyde, 3g Na₂Co₃, 4g KMnO₄ & 100 ml distilled water was mixed in a 250ml conical flask fitted with an air condenser. The mixture was heated gently for half an hour until all oily drops of benzaldehyde disappeared & MnO₂ was precipitated. The solution was Cooled, The filtrate with conc. H₂So₄ when white ppt of benzoic acid was obtained & washed with cold water. Purification was done as below recrystallized the benzoic acid from minimum quantity of boiling water using a little bone charcoal, it necessary collected the pure crystals by suction filtration, washed with a little cold water & dried it between the folds of a filter paper by pressing.

RESULT

Hence, the preparation of benzoic acid by the oxidation of benzaldehyde is done.

Appearance:White Shining crystals.

yield: 5gm

Melting point: 121°C

PRECAUTION:

1) All apparatus should be cleaned & dried before experiment.

2) Boil the solution until the oily drop benzaldehyde disappears.

3) Collect the crystal gently & carefully.