Reaction CXII.—Action of certain Bases on Acyl Chlorides

Reaction CXII. Action of certain Bases on Acyl Chlorides. (B., 34, 2070 J. pr., [2], 50, 479.)—When pyridine or quinoline act on an acid chloride, and the addition product which is formed treated with water, the acid anhydride is obtained (cf. Reaction CIX.). 

Preparation 221.—Benzoic Anhydride Anhydride of benzenemono-carboxylic acid). 

25 gms. (2 mols.) of benzoyl chloride are slowly added to 20 c.cs. of pyridine and 8 gms. of anhydrous sodium carbonate after J hour the whole is poured into water, the precipitate filtered and washed with cold water, and dried first on a porous plate, and then in a desiccator. It is recrystallised from petroleum ether, which is removed under reduced pressure. 

The anhydride may also be obtained by the action of acetic anhydride on benzoic acid. (B., 57, 431.) 

10 gms. methyl acetanilide are dissolved in 1 litre of dilute nitric acid (D. 1 029), and the solution heated to boiling under a reflux condenser. The liquid instantaneously assumes a brown colour, and after half an hour s heating becomes turbid and a yellow substance begins to separate out. Two hours heating is, however, necessary to complete the reaction. On cooling, the substance separates out in yellow crystals, which are recrystallised from aqueous alcohol. 

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