Measurement and correlation of liquid-liquid equilibrium data for water-acrylic acid-acetic acid-toluene

The liquid-liquid equilibrium(LLE) data for the quaternary system of water-acrylic acid-acetic acid-toluene at 293.15,303.15 and 313.15 K were measured in liquid-liquid equilibrium reactor under atmospheric pressure to screen the proper solvent for separating acrylic acid from water by the method of extraction followed by heteroazeotropic distillation.The reliability of the experimental LLE data was ascertained through Othmer-Tobias equation.The activity coefficient models of nonrandom two-liquid(NRTL) and universal quasi-chemical(UNIQUAC) were used to regress the LLE data of the investigated system.The parameters of the two models were obtained.The calculated values of LLE from the models were compared with the experimental values.The pseudo-ternary phase diagrams at different temperatures of the quaternary system were given.The results show that the deviations of root mean square from the NRTL model are smaller than those from the UNIQUAC model.