Vapor-liquid equilibrium (VLE) data of hexamethyl disiloxane (HMDSO,1) + butyl acetate (BAC,2),HMDSO + isobutyl acetate (IBAC,3) systems were measured by using the double circulating VLE still at 101.3 kPa.The thermodynamic consistencies of the VLE data were examined by the Herrington method.Experimental data were correlated by the Wilson,nonrandom two-liquid (NRTL),and universal quasichemical activity coefficient (UNIQUAC) parameter models.All of the models were satisfactorily correlated with the VLE data.The result showed that the UNIQUAC model was the most suitable one to represent experimental data for HMDSO + BAC system,and the NRTL model was the most suitable one for HMDSO + IBAC system.The two systems had no azeotropic phenomenon.