Study on Preparing Isolongifolene from Longifolene Catalyzed by Solid Superacid

The reactions of isomerization of longifolene catalyzed by SO~ 2- _4/TiO_2-ZrO_2 solid superacid are performed. From analyses of GC and GC-MS, the main product is isolongifolene from isomerization. The result shows that this catalyst has a high catalytic activity and a good selectivity to isomerization of longifolene. The factors affecting its catalytic activity are investigated. The result also shows that the optimum conditions for the preparation of SO~ 2- _4/TiO_2-ZrO_2 catalysts are as follows: n(Ti)∶n(Zr) 3∶1 , and calcination temperature 550 ℃. Under these conditions, the optimum conditions for isomerization of longifolene are as follows : reaction time 4 h, isomerization temperature 165 ℃, and ratio of solid superacid to longifolene mass part 4 %. Under these conditions, the conversion of longifolene is 99.1 %, and the yield of isolongifolene is 97.2 %. Furthermore, experiments on the effect of storage time of the catalysts on the reaction and the regeneration of catalysts are carried out.