Patent ID: 6426438
Filing Date: 2002-07-30
Classification: C07C,Y02P

Abstract:
A process for the preparation of 1,6-hexanediol and 6-hydroxycaproic acid or esters thereof with monoalcohols by catalytic hydrogenation of adipic acid, adipic acid monoesters or adipic acid diesters or streams of starting material which contain adipic acid or esters thereof as essential constituents, which comprises recycling the bottom product which is obtained in the distillation of the hydrogenation product, following removal of the hexanediol and hydroxycaproic acid or esters thereof, and essentially comprises oligomeric esters of 6-hydroxycaporic acid to the hydrogenation, and reacting the resulting mixture of starting material and recycle stream at from 100 to 300Â° C. and at from 10 to 300 bar in the liquid phase and at a molar ratio of carboxyl groups to be hydrogenated to hydrogen in the reactor of from 1:5 to 1:100 on hydrogenation catalysts.