Preparation of dimethyl adipate by the hydrogenation of dimethyl hex-3-endioate

Claim 1

A process for the preparation of dimethyl adipate by the hydrogenation of dimethyl hex-3-endioate, having the formula CH 3 O 2 CCH 2 CH═CHCH 2 CO 2 CH 3 , derived from the liquid phase oxidative carbonylation of 1,3-butadiene with a mixture of carbon monoxide and oxygen or an oxygen-containing gas and at least a stoichiometric amount of an acetal, ketal, carboxylic ortho ester, trialkylorthoborate or 1,1-dialkoxycycloalkane, at a temperature of from about 60° C. to 200° C. and pressures of from about 15 psig to about 5000 psig in the presence of a catalytic mixture of a platinum group metal compound or mixtures thereof and a copper (I), copper (II), iron (II) or iron (III) oxidant salt compound which comprises reacting under liquid phase conditions the dimethyl hex-3-endioate at a temperature of from about ambient to about 150° C. under a hydrogen pressure of from about 10 psig to 1000 psig in the presence of an effective amount of a hydrogenation catalyst to produce dimethyl adipate, and recovering said dimethyl adipate while at the same time recycling between about 20 weight percent and 80 weight percent of the dimethyl adipate produced by said hydrogenation of the dimethyl hex-3-endioate to the hydrogenator to control the temperature and remove the exothermic heat of reaction.