Synthesis of Trimethylolhexane Triheptyl Ester with Supported Phosphotungstic Acid Catalyst

A series of trimethylolhexane triheptyl esters were synthesized from trimethylolhexane with special kinds of supported phosphotungstic acid catalyst. The factors affecting catalyst activity and esterification conversion were discussed, and the optimum conditions for catalyst and trimethylolhexane triheptyl esters preparation were obtained. The optimum conditions for catalyst preparation were: m(support)/m(active component), 1/6; impregnation time,5 h; baking temperature, 320 ℃. The optimum conditions for esterification were: reaction time, 120 min; reaction temperature, 220 ℃;mass fraction of catalyst, 1.8%; mole ratio of haptanone and trimethylolhexane,3.7/1.0. The esterification conversion reached over 96.0% under the optimum conditions. Moreover, the catalyst was used repeatedly. The product was also verified by quality test and spectroscopic analysis.