Acids and their Simple Derivatives Acid chlorides

CARBOXYLIC ACIDS AND THEIR SIMPLE DERIVATIVES 1. ACID CHLORIDES 

The product is tested for the presence of phosphorus (PC13) by decomposing a few drops with a little warm water and evaporating the solution in a porcelain capsule. The residue is twice evaporated with concentrated nitric acid or with bromine water and is finally tested for phosphoric add in the usual way. If phosphorus is detected, the material should again be distilled with a few drops of glacial acetic acid. 

Into a round-bottomed flask (capacity 0-25 1.) fitted if possible with a ground-in condenser and containing 40 g. (0-33 mole) of dry 

The benzoyl chloride is now distilled from a wire gauze or over a faintly luminous flame. A long air condenser with a receiver similar to that used for acetyl chloride is employed. The first portion of the distillate, which consists chiefly of thionyl chloride, is fairly large (this material also may be used again). Then the bulk passes over at 194°-199°. Pure benzoyl chloride boils at 194°. Yield 40-42 g. 

Vacuum distillation, which yields a purer product, is also to be recommended here. Benzoyl chloride is a widely used laboratory product. 

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