Synthesis of tributyl citrate by the catalyst of heteropoly acid supported on modified montmorillonite

P-Mo-V heteropoly acid supported on modified montmorillonite was prepared by saturation impregnation and used as catalyst for synthesis of tributyl citrate.The effects of amount of the catalyst,reaction time,molar ratio,reaction temperature on the esterification rate were investigated.The optimum reaction conditions were obtained as follows:amount of the catalyst was 1.5% of citric acid used,reaction time was 3h,The molar ratio of n-butyl alcohol to citric acid was 5∶1,reaction temperature was 130℃.The catalyst with a great value can be used repeatedly.