Ebulliometric Determination and Prediction of Vapor–Liquid Equilibria for Binary Mixtures of Ethanol and Ethyl Hexanoate.

The objective of this study is to measure vapor–liquid equilibria (VLE) data for an ethanol fatty acid ethyl ester (FAEE) system. VLE data for the binary system ethanol ethyl hexanoate were determined at pressures of (40.00 to 101.3) kPa using an ebulliometer, which could compensate for vapor hold-up. The hold-up compensable ebulliometer was designed for this study, and the experimental apparatus and procedure were verified by measuring the VLE data for ethanol p-xylene at pressures of (40.00 to 101.3) kPa. The densities at 298.15 K for pure components investigated in this study were also measured by a densimeter. The experimental VLE data of the two binary mixtures, ethanol p-xylene and ethanol ethyl hexanoate, were represented by the Wilson and nonrandom two-liquid (NRTL) models. The analytical solutions of groups (ASOG) and modified universal functional activity coefficient (UNIFAC, Dortmund) group contribution models were also used to predict the VLE behavior of these binary mixtures. The VLE data could be applied for the production of a biodiesel fuel synthesized from fatty acid ethyl esters using supercritical ethanol without a catalyst. [ABSTRACT FROM AUTHOR]