| abstract |
The invention relates to a method for producing 1,6 hexane diol from a mixture of carboxylic acids containing hexanedioic acid, 6-hydroxy caproic acid and small quantities of 1,4 cyclohexane diol, said mixture being a by-product obtained during the oxidation of cyclohexane to cyclohexanone/cyclohexanol using oxygen or gases containing oxygen by the extraction of water from the reaction mixture, the method including the esterification of the acids and subsequent hydrogenation. According to said method, the alcohol is separated from the mixtures of alcohols and low-boilers obtained after esterification and/or hydrogenation by a membrane system and is returned to the esterification step. |