A new process for the synthesis of dimethyl maleate:II study on the conditions of esterification

This article studied using solid molecule sieves as the catalyst of the esterification of methanol and maleic anhydride.The investigation focused on the effects of esterification conditions on both conversion of maleic anhydride and reaction selectivity.Reaction temperature,reaction time,amount of the catalyst and molar ratio of the raw materials were studied.Experimental results indicate that the increase of reaction temperature benefits the production of dimethyl maleate,with the optimum range being 105 ~110℃.Similarly,increases of the ratio of methanol to maleic anhydride,reaction time and catalyst amount also help the production of the goal ester.With the amount of the catalyst being at 0.5 percent of the maleic anhydride,the ratio of methanol to maleic anhydride being 3∶1 and reacting 12h at 110℃,the yield of dimethyl maleate may be over 93%.The catalyst can be reused for three times without substantial efficiency loss.