Carboxylic ester prodn. with purificn. by ozone - to reduce colour, useful as polymer plasticisers

摘要

Prodn. of caboxylic esters (I) comprises first reacting acids (or their anhydrides) with alcohols at mole ratio 1:2.2-2.6 at 130-200 degrees C. The reaction mixt. is then treated at 15-90 degrees C, esp. 50-70 degrees C with a stream of air contg. 5-50, esp. 15-20 mg ozone per 1. Pref. esterification is carried out in presence of a catalyst, esp. an acid or orthotitanic acid deriv. (I) are plsticisers for a wide range of polymers, O3 treatment improves prod. colour (10 units on the Hazen scale) and the quality of the recovered excess alcohol is equal to that of the starting alcohol so it can be reused. No energy-intensive distillative purifcn. is necessary and very pure starting materials are not needed.