Catalytic synthesis of 2,4-D butyl ester by silica sulfuric acid

Silica sulfuric acid was used as the catalyst for synthesis of 2,4-D butyl ester from 2,4-dichlorophenoxyacetic acid(2,4-D) and n-butyl alcohol.The effects of catalyst amounts,molar ratio of alcohol to acid and reaction time on the product yield was investigated.The optimum conditions were as follows:1.4% catalyst based on 2,4-dichlorophenoxyacetic acid,molar ratio of 2,4-dichlorophenoxyacetic acid to n-butyl alcohol 1∶ 10,and reaction time 1.0 h.Under the optimum conditions,the yield of 2,4-D butyl ester was 98.7%.