Evaluation of the 2,2′,2″-Nitrilotrisethanol as an Entrainer for Separation of an Isopropanol + Water Mixture

Abstract

The present study focuses on the investigation of 2,2′,2″-nitrilotrisethanol (triethanolamine) as an entrainer to effect the separation of an isopropanol–water mixture. The vapor–liquid equilibrium (VLE) data were measured for the binary systems isopropanol + triethanolamine and water + triethanolamine using an improved Othmer still at 101.3 kPa. Experimental data for the ternary mixture isopropanol + water + triethanolamine were also studied for different entrainer concentrations. Three initial triethanolamine concentrations, 5 mol %, 10 mol %, and 15 mol %, were examined in the feed solution for VLE experiments. The results demonstrated that the addition of triethanolamine in the isopropanol + water mixture produces a considerable increment in the relative volatility, which could eliminate the azeotrope successfully. Hence, triethanolamine was found to be an effective entrainer for breaking the isopropanol + water azeotrope. Further, the NRTL model was used for fitting the experimental VLE data, and the binary interaction parameters were regressed. The estimated values for binary and ternary systems agreed well with the experimental data. The overall average deviations for the vapor-phase mole fraction and equilibrium temperature between the experiment and correlation were found to be 0.09 and 0.40 K, respectively. Moreover, the thermodynamic consistency check of experimental VLE data was performed by using the modified McDermott–Ellis test and Wisniak’s L–W test.