Activity coefficients based on heat of mixing data and vapor-liquid equilibria data

Abstract

Activity coefficients based on heat of mixing data and vapor-liquid equilibrium (VLE) data were studied. Published data of thirteen binary systems were correlated using the Wilson and UNIQUAC equations in order to investigate interaction parameters of these models. Based on VLE data, both models gave a good prediction of pressures for the thirteen binary systems since the maximum percent absolute average deviation between the predicted and experimental pressures is 2.26%. With these parameters both equations gave poor prediction of HE in all cases. The Wilson gave the best prediction of 11.01 %AAD for the 1,2-dichloroethane with di-n-butyl ether system at 288.15 K. Based on HE data, prediction of HE for the binary systems with the UNIQUAC equation is better than the Wilson model except for the 1,2-dichloroethane+di-n-butyl ether, 1,1,1-trichloroethane+di-n-ethyl ether, and ethyl formate+benzene systems. Prediction of pressure based on these parameters obtained by the UNIQUAC is more suitable than the Wilson except for the 1,2-epoxybutane+alkanols, ethyl formate+benzene, ethyl formate+cyclohexane, and butanenitrile+2-butanol systems. The UNIQUAC gave the best prediction for the 1-chlorpentane and di-n-butyl ether system at 323.15 K. Finally, these parameters are sensitive on HE data and rarely sensitive on VLE data.