Vapor–Liquid Equilibria of the Aqueous and Organic Mixtures Composed of Dipropylene Glycol Methyl Ether, Dipropylene Glycol n-Butyl Ether, and Propylene Glycol n-Butyl Ether. Part II: Modeling Based on the NRTL-PR Model

Abstract

Further to Part I of our study of glycol ether binary mixtures [Dimitrov, O.; Ind. Eng. Chem. Res. 2021, 60, 9602−9612], this second part is concentrated around the vapor–liquid equilibrium (VLE) modeling of binary mixtures involving the three glycol ethers previously studied experimentally. The authors propose to use the NRTL-PR model for the representation of these nonideal mixtures. The main difficulties of modeling related to very low vapor pressures and the approach to cope with them are highlighted. The unknown critical parameters for DPM, DPnB, and PnB were determined using robust group contribution methods. However, the experimental values of these parameters have never been published before. The main goal of the authors was to obtain the most satisfactory representation of the experimental data provided in Part I. Some issues that mostly occurred in mixtures involving the PnB as well as in mixtures having very low vapor pressures were encountered. Nevertheless, in general a satisfactory representation of measured points has been obtained regardless of those issues.