Comparison of UNIQUAC and NRTL Models in Thermodynamic Modeling of Liquid-Liquid Equilibrium of Dibutyl Ether+ Alcohol+ Water

Purification of alcohol is one of the research that is ongoing today. Meanwhile, liquid-liquid extraction is one of the most important methods of purification. Therefore, in this study, the purification of different alcohols was investigated by extraction using dibutyl ether solvent. Thermodynamic modeling of liquid-liquid equilibrium (LLE) of dibutyl ether+ alcohol+ water system was investigated at different temperatures. For this purpose, UNIQUAC and NRTL thermodynamic models were used and intermolecular interaction parameters were considered as a function of temperature. These parameters were obtained by optimizing an objective function. The objective function was considered as the mean-square deviation of the experimental data and the results of the models. The results of the modeling show the high accuracy of both models in estimating the composition of the component in different phases. The root means square deviation for UNIQUAC and NRTL models were 0.0191 and 0.0112, respectively. Moreover, the results show that dibutyl ether for the separation of heavier alcohols has a higher distribution coefficient and selectivity.