JPS56158734A - Preparation of p-n-alkylbenzoic acid - Google Patents

Abstract

PURPOSE: To obtain the titled compound of high purity useful as a liquid crystal material, etc., readily in a simple operation and inexpensively, by the reaction of p-formylbenzoic acid with a ketone in the presence of a basis catalyst, and the reduction of the resultant product.

CONSTITUTION: p-Formylbenzoic acid expressed by formula I is reacted with a methyl n-alkyl ketone expressed by formula II (R is n-alkyl) in the presence of a basic catalyst, preferably by the addition of water in an amount equal to that of the ketone, at 0W50°C. The resultant reaction mixture containing an intermediate compound expressed by formula III is acidified with a mineral acid, e.g. hydrochloric acid, and the intermediate compound expressed by formula III is dehydrated, preferably under heating, to produce an unsaturated ketone expressed by formula IV. Then the vinylene group of the unsaturated ketone is hydrogenated into an ethylene group to give a saturated ketone, which is then reduced to afford the aimed compound.

EFFECT: An expensive reagent, e.g., AlCl₃, is not required and the waste water is treated simply.

COPYRIGHT: (C)1981,JPO&Japio