| 摘要 |
<p>1415486 Menthol BAYER AG 20 March 1974 [24 March 1973] 12340/74 Heading C2C [Also in Division B1] The invention comprises a process for the production of d,l-menthol by catalytically hydrogenating compounds which have the carbon skeleton of menthol with at least one double bond and which are substituted by oxygen in the 4-position, and/or by re-arranging optically active or inactive stereo-isomers of menthol at an elevated temperature and under pressure, wherein hydrogenation and/or rearrangement is carried out continuously using a fixed-bed cobalt catalyst containing 10 to 40% by weight of manganese, based on the total quantity of cobalt and manganese, using a quantity of hydrogen per mol amounting to at at least 10 times the quantity required to hydrogenate a benzene nucleus, at a temperature in the range from 170‹ to 220‹ C. and under a pressure of at least 25 bars.</p> |
