Studies On Preparation Of Methyl P-tertbutyl Benzoate Catalyzed By Acidic Catalyst

Methyl p-tert-butylbenzoate,an important intermediate for the chemical and medication industry,is widely applied in the chemical industry,pharmaceutical industry as well as in the cosmetics,perfume and essence.The great annual demand draw our attention to investigate better synthetic methods.In this paper,taking p-tert-butylbenzoic acid and methanol as raw materials,STS solid superacid,ionic liquid,sulfonic resin and ZSM-5 zeolite as different catalysts,we found that sulfonic resin and ionic liquid showed the highest catalytic activity.The quantitative analysis of product conversion was determined by acid-base titration.Vacuum distillation-extraction-vacuum distillation method was used to purify the product.Six kinds of—SO₃H functionalized ionic liquid with high purity,good water stability were prepared and the corresponding esterification reaction was done to find the best ionic liquid catalyst.The results showed that all these sulfonic Br?nsted acids qualified good catalytic activity and the 1-?4-sulfonic acid?butyl-pyridinium hydrosulfate ionic liquid outstood among them.Various reaction factors influencing the yield of the target product were discussed.The optimum reaction conditions were as follows:the molar ratio of methanol,p-tert-butylbenzoic acid to ionic liquid was 100:10:1,the reaction time 2.5 h,the reaction temperature 140?.The conversion rate can reach 90%.Three different kinds of sulfonic resin were prepared as catalyst to synthesize of methyl p-tert-butylbenzoate.The results revealed that the catalytic activity was dependent on the acid amount.D001 sulfonic resin showed highest catalytic activity.The optimum reaction conditions were as follows:the molar ratio of methanol to p-tert-butylbenzoic acid was 8:1,the catalyst percentage 12.5 wt.%,the reaction time 3 h,the reaction temperature130?.The conversion rate can reach 90%.Both the ionic liquid and sulfonic resin are solid acid catalysts,which can be directly separated from the reaction system and recycled.The prepared solid acid catalysts exhibited good activity and excellent stability,and enjoyed predictable industrial application prospect.