Patent ID: 7449609

Claim:
A process for preparing 1 ,6-hexanediol comprising hydrogenating dialkyl adipates, alkyl 6-hydroxycaproates and 1 ,4-cyclohexanedione and 4-hydroxycyclohexan- 1-one as ester mixtures comprising impurities, the process further comprising: a) freeing the resulting esterification mixture of excess alcohol and low boilers in a first distillation stage; b) carrying out a separation of the bottom product in a second distillation stage into an ester fraction substantially free of 1 ,4-cyclohexanediols and a fraction comprising at least the majority of the 1,4-cyclohexanediols; c) catalytically hydrogenating the ester fraction substantially free of 1,4-cyclohexanediols; and d) in a purifying distillation stage, obtaining 1 ,6-hexanediol from the hydrogenation effluent in a manner known per se, which comprises selectively hydrogenating the ester mixture before stage a) and/or before stage b) (purifying hydrogenation).