Synthesis Of Dihydromyrcenol Catalyzed By Supported Ion Exchange Resin

Dihydromyrcenol (DHMOH), which has the flavors of fresh flowers and white lemon fruits, is one of the most popular perfumes in the world. There are two ways to synthesize it, that is, indirect and direct hydration. Traditional, the indirect hydration for industrial production, which uses H2SO4 as the catalyst, is encountered by the problems of long production period and great damages to the environment and apparatus. The one-step hydration where the dihydromyrcene (DHM) is catalyzed directly into DHMOH by solid acids, is therefore, widely studied recently. However, due to the low transforming rate of DHM and the low utilization rate of the catalyst, the new method is urged for improvement for industrial application.In this thesis, the preparation process of a supported solid catalyst and the optimum conditions of synthesizing DHMOH in the present of the catalyst were studied.The macroporous and strong acidic cation exchange resin was selected as the carriers which supported the various active ingredients (metal ions) and thus the supported solid catalyst were prepared. The experimental results indicated that this kind of catalyst applied in the synthesis of DHMOH had a good catalyzing function. According to the basic parameters and related data measurement, D61 resin was suitable for being the industrial solid catalyst. SnCl4/D61 was the highest activity of hydration catalyst. Furthermore, the influences of the time and the temperature for the preparation of the supported catalyst SnCl4/D61, and the amount of tin tetrachloride were studied on the transforming rate and the selectivity of the hydration reaction. The conjugating groups forming the center of the new strong acid was proved through the structural analysis of the new kind of catalyst with IR.In terms of the single-factor and multi-level experiments, the appropriate results were obtained when the volume ratio of DHM, H2O and isopropanol was 10:20:20, the catalyst amount was 12g and the reaction time was 36 hours.Under the appropriate reaction conditions, the comparisons of D61 and D61·SnCl4 on the catalyzing activities on the hydration reactions, the stabilization with the existence of metal ions, and the catalyzing life, showed that SnCl4/D61 had a higher catalyzing activity with the transforming rate approximate 98.7% because in the circumstance of metal ions, SnCl4/D61 wouldn't be exchanged by the cations and ose its activity due to its new acidic center. Even after repeated eight batches, SnCl4/D61 didn't lose its activity significantly and the yield ratio was still above 90%.