Preparation of p-Hydroxybenzoic Acid Ester with Insoluble Salt of Heteropoly-acid as Catalyst

Triethanolamine salt of tungstosilicic acid was prepared from tungstosilicic acid and triethanolamine,and was used in the preparation of p hydroxybenzoic acid ester as catalyst for the first time.The influences of such factors as the amount of the catalyst,the mole ratio of alcohol to acid and reacton time on the yield of ester were investigated.The results showed that the salt of heteropoly acid had rather high catalytic activity,the yield of the ester reached 91.6%,and the catalyst is insoluble in alcohol and can be recovered and reused for more than five times.