Study On The Vapor-Liquid Equilibria For The Binary Systems Maleic Anhydride And Organic Solvents

In this paper, vapor-liquid equilibrium data(T,P) for the two binary systems maleic anhydride (MAN) + di-isobutyl hexahydrophthalate (DIBE) and maleic anhydride + di-n-butyl phthalate (DBP) at different feed compositions(qi) at low pressures were measured with a small modified ebulliometer. These data were used to calculate vapor-liquid equilibrium compositions(xi,yi) for the two binary system at 2.666,5.333,7.999kPa by use of the NRTL and Wilson models. At the same time, the parameters of the NRTL and Wilson models for the two binary systems were obtained. It was found that the NRTL model was more suitable than the Wilson model for the two binary systems by comparing the two model's correlation accuracy. So NRTL model was chosen only to correlate the VLE data and calculate the vapor-liquid equilibria compositions(xi,yi) for the two binary systems at 413.15,433.15 and 453.15K. In this paper, the predictions to VLE data for the two binary systems at 2.666,5.333,7.999kPa and at 413,433,453K were performed by use of the UNIFAC model. Predicted results are compared with those of present experiments, and show good agreement. Furthermore, VLE data are predicted at 343.15K,353.15K and 363.15K for the two binary systems, which are close to the operating temperatures in the process of MAN's absorption, because it is difficult to obtain the VLE data from experiment. In addition, in order to get the Antonie's coefficients of the pure MAN and DIBE, the saturated vapor pressures data were measured with the modified ebulliometer. Meanwhile, the enthalpy of vaporization ( ΔvapHm*) of DBP and DIBE were obtained according to the equation of Clausius–Clapeyron.