Process for the preparation of D,L-menthol

摘要

A continuous process is described for the preparation of D,L-menthol by catalytic hydrogenation of compounds which have the carbon skeleton of p-menthane containing at least one double bond and are 3-substituted by oxygen using hydrogen and/or by rearrangement of stereoisomers of menthol in the presence of hydrogen at temperatures of 150 DEG to 230 DEG C. and at pressures of 25 to 350 bar on fixed-bed catalysts made of support-free reduced shaped bodies made of pressed powders of cobalt (hydr)oxide, manganese (hydr)oxide, alkaline earth metal (hydr)oxides and, optionally, (hydr)oxides of elements of subgroup V and/or VI of the Periodic Table of the Elements.