Bonus Esterification Process Of Acetyl Tri(2-Amyl) Citrate

There exist disadvantages of long route, high cost, the refined difficult of crude product in the traditional acetyl tri (2-amyl) citrate production process. For this, Reactive Distillation (RD) was introduced in order to improve the defects. Reaction and distillation were integrated in the RD column. The alcohol production process was eliminated, so the conversion rate of citric acid was effectively improved, and thus the subsequent refining load and energy consumption. In this research, the characteristics of exothermic reaction was taken full used as the reboiler of gasoline and acetic acid, so the use of the reaction heat was realized. The original secondary alcohol refine, esterification and dehydrated three work produce was reduced to one react and absorb produce, thus equipment investment and energy consumption was greatly reduced. In this research, Aspen Plus simulation software was used, and the continuous production of Acetyl tri (2-amyl) citrate using RD technology was studied systematically through the method of combining experiment and Aspen Plus simulation together.By small scale experiment in the laboratory, the reaction kinetics between citric acid and olefins in the light gasoline was studied. The experiment results showed that the optimal reaction temperature was120-130℃, the strongly acidic exchange resin as the suitable catalyst, and the reaction kinetic parameters were:k=3.55x103mol·L-1min-1, Ea=3.32×105J·mol-1,A=8.53×1011.On the basis of the test, RD pilot was constructed to carry out continuous production. By controlling proper reflux ratio, a continuous high purity of gasoline was recovered from the top of the column while the crude product was collected from the bottom. The process operating parameters were researched to provide data for industrial design. The temperature of the top of column was75.3℃. The temperature of the top of rectification section was106.5℃. The temperature of the bottom of rectification section was125.2℃. The temperature of the bottom of the column was155.2℃. The petrol content of top of the column was100%. The Acetyl tri (2-amyl) citrate percent of bottom was79.39%, while the sec-amyl acetate was20.11%, the others were unreacted citric acid and acetic acid sum to0.5%.The process was simulated by Aspen Plus and the good agreement between simulation result and the pilot experiment indicated that the software can be used for Acetyl tri (2-amyl) citrate of RD process simulation, preliminary design of the continuous RD process for Acetyl tri (2-amyl) citrate production was carried out, the process equipment and technological conditions were designed and optimized by the use of computer simulation. The appropriate operating parameters were:total plate number17, with10to reaction,4for distillation,3for stripping; reflux ratio2.0; pressure10atm; the flow rate of citric acid was16.89kmol/h, the flow rate of acetic anhydride was16.89kmol/h too, and the mixed acid was feed at the5th plate; the flow rate of petrol was187.69kmol/h, feed at the14th plate. Under these conditions, containing a small amount of olefin pure petrol was extracted from the top of the column, the mixed ester of acetyl tri (2-amyl) citrate and sec-butyl acetate was extracted from the bottom of the column. By distillation the purity of Acetyl tri (2-amyl) citrate was up to99.5%.