Isobaric vapour-liquid equilibrium data for the binary systems of polyoxymethylene dimethyl ethers with methanol, methylal and ternary system of methylal + methanol + polyoxymethylene dimethyl ethers at 50.0 kPa

Abstract

Polyoxymethylene dimethyl ethers (PODEn) are excellent diesel blending components that can reduce pollution compared to conventional diesel. In this work, isobaric vapour-liquid equilibrium (VLE) data for the two binary systems of (methanol + PODE3), (methylal + PODE3) and ternary system of (methylal + methanol + PODE3) at 50.0 kPa were measured in an Ellis equilibrium still. The thermodynamic consistency of the experimental data was checked by the Herington area method and Van Ness method. All systems passed thermodynamic consistency test. The UNIFAC and NRTL models were applied to correlate the experimental data, the root-mean-square deviation (RMSD) and the average absolute deviation (AAD) for the temperature (T) and the molar fraction of the vapour phase (y1) were obtained. The results demonstrate that the UNIFAC model is more accurate than the NRTL model for the studied systems. Therefore, the UNIFAC model can predict the VLE data of PODEn systems accurately. The VLE phase diagrams of studied systems were obtained and they were useful for the separations of PODEn.