Experimental isobaric vapor–liquid equilibrium at sub-atmospheric and local atmospheric pressures, volumetric properties and molar refractivity from 293.15 to 313.15 K of water + triethylene glycol

Abstract

Experimental isobaric vapor–liquid equilibrium data for the binary system of water+triethylene glycol were obtained at sub-atmospheric pressures of 53.33, 66.66, 79.99kPa and local atmospheric pressure of 95.99kPa over the entire composition range using a modified Sweitoslawsky-type ebulliometer. The experimental data was correlated using Wilson and NRTL models. Wilson model was found to better represent the calculation results. The measured densities and refractive indices over the entire composition range of water+triethylene glycol are reported from 293.15 to 313.15K at local atmospheric pressure of 95.99kPa. Excess molar volume, partial molar volume and deviations in molar refractivity were evaluated and fitted to the Redlich–Kister equation. Excess molar volumes were found to be negative at all temperatures and the deviation from ideality decreased with increase in temperature. Different mixing rules were also investigated for predicting the refractive indices of the binary mixture and are reported in terms of their average percentage deviation.