Adipic Acid → Cyclohexanol

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Reaction Steps

Conventionally, 1,6-hexanediol is produced from an organic acid mixture containing adipic acid, hydroxycapronic acid and glutaric acid, wherein the organic acid mixture is by-produced during the production of cyclohexanone and/or cyclohexanol by oxidation of cyclohexane with air. For producing 1,6-hexanediol, the organic acid mixture is subjected to esterification and then to hydrogenation in the presence of a copper catalyst to thereby obtain 1,6-hexanediol, and the obtained 1,6-hexanediol is purified by distillation. 1,6-Hexanediol which is conventionally produced in the above-mentioned manner contains 1,4-cyclohexanediol, and such 1,6-hexanediol is not suitable as a raw material for producing the polycarbonate diol of the present invention. The boiling point of 1,4-cyclohexanediol and the boiling point of 1,6-hexanediol are very close to each other and, therefore, it is difficult to decrease the amount of 1,4-cyclohexanediol in 1,6-hexanediol to the above-mentioned preferred level (i.e., 0.5% by weight or less) by distillation.

Provenance & Evidence