| 摘要 |
<p>There is provided a process for preparing 1,6-hexanediol by esterifying a carboxylic acid mixture resulted from oxidation of cyclohexane with oxygen, and then hydrogenating the esters, which substantially does not contain a compound leading to a high ester value. A process for preparing 1,6-hexanediol from a carboxylic acid mixture containing adipic acid and 6-hydroxycaproic acid, the carboxylic acid mixture is obtained as a by-product in oxidization of cyclohexane to cyclohexanone/cyclohexanol using oxygen or an oxygen-containing gas, the process comprises esterifying the acids with an alcohol, followed by hydrogenation, and the process is characterized by comprising the following steps of:
a) separating a component having a boiling point lower than that of water and the alcohol used in the esterification from a mixture obtained by the hydrogenation in a first distillation step;
b) separating an EV component having a boiling point higher than that of 1,6-hexanediol further in a second distillation step;
c) separating an EV component having a boiling point lower than that of 1,6-hexanediol further in a third distillation step; and then
d) obtaining 1,6-hexanediol in a fourth distillation step,
in this order.</p> |
