Theme: Study On The Esterification Reaction With Pervaporation Membrane

This article studied on the esterification of acetic acid with n-butanol coupling with pervaporation membrane. PVA and NaA was used as the dehydration membranes studied of it's selectivity and permeability.Firstly, analyzed the structural feature of the inorganic membrane-zeolite NaA membrane and the organic membrane-polyvinyl alcohol (PVA) membrane by the electron microscope, then inspecting their separation performance in the ethyl alcohol/water dual system, the effect of the polymerization degree, feed concentration, downstream side pressure and temperature on the separation properties such as permeation flux, separation factor and pervaporation separation index (PSI) were studied.With the synthesis of butyl acetate as a target reaction system by pervaporation esterification in a composite membrane reactor the effect of several factor like the feed molar ratio of alcohol to acid, ratio of membrane area to feed volume, membrane sepration property and reaction temperature, on the shift of the chemical equilibrium were investigated in detail.The result of the zeolite NaA membrane used in the esterifacation reaction indicated that in the condition of temperature 105℃,the ratio of alcohol to acid 1.5, the catalyst mass fraction 5wt% and the ratio of membrane area to volume of solution is 32.76, the esterification production rate achieves the maximum.Compared with the esterifacation reaction which without pervaporation membrane, the esterification production rate increased 27.68%, compared with the esterifacation reaction which with the water separator, the esterification production rate increased 7.64%.PVA membranes preferentially permeate water over the organic compounds, and its permselectivity follow the order of water> acetic acid> n-butyl acetate, the membrane was especially selective to water permeation.The result of the PVA membrane used in the esterifacation reaction indicated: when the temperature is 80-90℃,ratio of alcohol to acid equal to 1.5, the catalyst concentration on the ratio of conversion equal to 5wt% and the ratio of membrane area to volume of solution is 28.4, the esterification production rate achieves the maximum. Compared with the esterifacation reaction which without pervaporation membrane, the esterification production rate increased 28.72%, compared with the esterifacation reaction which with the water separator, the esterification production rate increased 8.98%.According to material balance, the esterification reaction kinetics and the quaternary system pervaporation correlation, the hybird process of the esterification of acetic acid with n-butanol in batch reactor, coupled with pervaporation through PVA membrane were studied and a mathematic model was established. The above differential equations can be solved numerically by using computer language. The calculation results were valided by experimental data. In this work, the influnces of different parameters were investigated theoretically on the basis of the model. Therefore some suggestions about the hybrid process in the industry production of n-butyl acetate were presented.