| abstract |
A method is provided for obtaining highly pure 1,6-hexanediol in which the contents of impurities such as 1,4-cyclohexanediol, 1,5-hexanediol, 1,2-cyclohexanediol, 1,7-pentanediol, 1,5-pentanediol and high boiling point components are significantly reduced. n This process for producing 1,6-hexanediol from cyclohexane comprises the steps of:n (1) treating an aqueous extraction concentrate of a reaction mixture obtained by oxidation of cyclohexane with a lower alcohol to esterify monocarboxylic acids and dicarboxylic acids contained in the extract, and simultaneously remove and separate by distillation water, excess lower alcohols and carboxylic acid esters; (2) converting oligomer esters contained in the bottom liquid to carboxylic acid esters by depolymerizing the oligomer esters at a high temperature and high pressure in the presence of a lower alcohol and a catalyst; and (3) hydrogenating the carboxylic acid esters distilled off in the step (1) and the carboxylic acid esters obtained in the step (2) either respectively or collectively to convert to 1,6-hexanediol. |