Synthesis of tributyl citrate catalyzed by phosphotungstic acid supported on palygorskite

Phosphotungstic acid supported on palygorskite was prepared by adsorption and reflux evaporation method,and characterized by IR,XRD and TG.Tributyl citrate was synthesized using palygorskite-supported phosphotungstic acid as the catalyst.The reaction condition was investigated by orthogonal experiment,with optimal reaction condition obtained as follows: n(citric acid)∶n(n-butanol)=1∶4,reaction time 3.0 h,dosage of the catalyst=1.0 g,reaction temperature 145 ℃.Esterification yield of 86.4% was obtained under the optimal condition.The catalyst can be used for several times.