Preparation Of Solid Base Catalyst For Synthesis Of DMC By Transesterification

The methods and catalysts to synthesize DMC is future studied for its environmental friendliness. For the moment, the catalysts used in transesterification methods is CH₃ONa/CH₃OH solution, and it is very hard to separate from products. In this paper, a kind of solid based catalyst was prepared in order to instead of the homogeneous catalysts.The alkali metal compound and alkaline earth metal compound was chose as the active component, the effects of different supporters and precursors for the catalytic activity are studied and it was found that the impregnation using Ca(NO₃)₂ solution as the precursor and ZrO2 as the supporter was a good method to prepare the CaO/ZrO₂ catalyst. The optimal preparation parameters was that: the loading amount of CaO was 40(wt)%, the calcinations temperature was 600℃and the calcinations time was 6h. At the same time, the results show that the catalyst has good stability.This solid base catalyst was characterized by Hammett titration method, and the total base amounts was determined by titration. The results show that the base strength of the prepared catalysts was between 15 and 18.2, and the catalytic activities were correlated closely with its basic strength and total base amounts.On the other hand, the transterification reaction conditions were discussed, by orthogonality experiment, the optimized parameters were determined: the MeOH/PC mol ratio at 6:1, the reaction temperature at 65℃, the catalyst dosage at 3%, and the reaction time 120min.the yield of DMC can reach to about 60% at this conditions.