1,6-Hexanediol → Cyclohexanol cyclohexanone

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Reaction Steps

The present invention relates to a process for preparing 1,6-hexanediol which has a purity of at least 99% and is, in particular, essentially free of 1,4-cyclohexanediols from a carboxylic acid mixture obtained in the oxidation of cyclohexane to cyclohexanone/cyclohexanol using oxygen or oxygen-containing gases after water extraction of the reaction mixture followed by extraction with aqueous sodium hydroxide solution, which comprises neutralization of the extract, fractionation of the organic phase into a low boiler fraction and a high boiler fraction, esterification of the latter, fractionation of the esterification mixture to give an ester fraction which is free of 1,4-cyclohexanediols, hydrogenation of this ester fraction and purification of the 1,6-hexanediol by distillation. EP-A 883 590 discloses a process for preparing 1,6-hexanediol from a carboxylic acid mixture comprising adipic acid, 6-hydroxycaproic acid and small amounts of 1,4-cyclohexanediols which is obtained as by-product in the oxidation of cyclohexane to cyclohexanone/cyclohexanol using oxygen or oxygen-containing gases after water extraction of the reaction mixture, by esterification of the acids and hydrogenation, in which

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