| 摘要 |
Compsns. rich in cis- and trans-p-menthane-di:ol content, are prepd. from citronellal and eucalyptus-citriodorata. These essential oils are treated in the presence of water with 10-50 wt.% of a strong cationic pref. macroporous acid form, ion-exchange-resin, having a specific surface area of 50-200 sq.m/g. This heterogeneous phase treatment causes, via proton-catalysed ring - closure and hydration - a 75-85 % conversion of the citronellal content. The level of the simultaneously produced acetal by-prod. does not reach 1.5 wt.%. Cis- and trans-p-menthane-3,8-diol contg. prepns. are tolerated well by the human epidermis, when used in natural insect repellent environment-friendly prods. Prepn. technology is efficient. |
