Study Of Synthesis Of Ethyl Acetate With Heteropoly As Catalysts

A series of heteropoly acids with the Keggin structure have been prepared by ether extraction method,including 12-tungstophosphoric acid,12-molybdophosphoric acid and 12-silicotungstic acid. In addition, a series of supported heteropoly acids have also been prepared with activated carbon,silica gele,Al2O3 and Y-type zeolite as their supports by different methods such as reflux adsorption and impregnation.The catalysts were characterized by Hammeet,IR,XRD and DTA.Heteropoly acid was mixed with p-toluene sulfonic acid and oxalic acid in certain proportion for the first time. The mixed catalyst was used in the esterification.The catalytic activity was investigated by measurement of water velocity. The experimental results show that the mixed acid has better catalytic activity than heteropoly acid only. The heteropoly acid catalysts were used in the esterification. The catalytic activity of different heteropoly acids and supported heteropoly acids were investigated by measurement of acid content and water velocity. Then the catalysts of high activity and selectivity were selected to be used in the preparation of ethyl acetate.Ethyl acetate was synthesized by ethanol with acetic acid as raw material. The experiments were engaged in batch process and series process. In the intermittent,the molar ratio of acetate to ethanol,the content of the catalysts,the time of reaction and the content of water carrier were studied. Then the best reaction condition was determined. In addition,in the consecution method,the rate of the raw material input, the ratio of refluxing and the content of the catalyst were studied. Then the best reaction condition was also determined.It was proved that 12-tungstophosphoric acid,PW12/C and PW12/SiO2 are good catalysts to esterification. In the intermittent reaction, the yield of each catalyst was 93.78%,90.68% and 91.56% . In the consecution,the yield of each catalyst was 97.32 %,94.18% and 92.08%. And the catalysts have no corrosion and could be reused. High activity and selectivity was attained. We can foresee a bright future for the application of heteropoly acid catalyst to chemical industry.The mixed hetreopoly acid used in the esterification has high activity and selectivity. In the intermittent reaction,the yield is 95.88%. In the consecution,the yield of each catalyst was 98.36 %. It was higher than tungstophosphoric acids.