Abstract:The parameters of the molecular interaction volume model (MIVM) were solved by Newton iteration method based on the experimental values of the infinite dilute activity coefficient of a single element at different temperatures, and the activity coefficient of the full concentration of the binary system was calculated by using the obtained parameters. Compared with the experimental value of activity coefficient of binary system at full concentration, the verification results show that the total average relative error of MIVM in alloy binary system and ionic liquid system were 4.21% and 9.60% respectively, which shows this method has better accuracy and reliability, and the method of determining model parameters by using infinite dilute activity coefficient of single component has not been reported yet. On this basis, the activity coefficients of water and 1-butanol in different ionic liquids were calculated by MIVM and NRTL equations. The total average relative errors were 0.64% and 8.39% (water + ionic liquid), 1.16% and 3.47% (butanol + ionic liquid), respectively. This shows that the accuracy of MIVM is better than that of NRTL equation in the calculation of infinite dilute activity coefficient of water/butanol + ionic liquid binary system. Therefore, the activity coefficients of the binary system consisting of [DoMIM][NTf2], [EMIM][TCM], [N1112OH][NTf2] with water and 1-butanol were predicted. This provides more reliable thermodynamic basic data for industrial production of 1-butanol and an alternative thermodynamic model for the calculation of thermodynamic properties of ionic liquid systems.