Experimental determination and theoretical modeling of isobaric vapor–liquid equilibria, liquid mass density, surface tension and dynamic viscosity for the methyl butyrate and tert-butanol binary mixture

Abstract

The purpose of this work is to provide consistent experimental measurements on the vapor–liquid equilibria (VLE) at the isobaric conditions of 50.00, 75.00 and 94.00 kPa, as well as experimental determinations of the liquid mass densities, the surface tensions and the dynamic viscosities at 298.15 K and 101.3 kPa of the methyl butyrate + tert-butanol binary system within the whole composition range. For these goals, a Gillespie-type cell is used to carry out the VLE measurements, whereas an oscillating densimeter, a maximum differential bubble pressure tensiometer, and a rotating viscometer are used to quantify the remaining physical properties. The thermodynamical quality of the reported VLE data is validated by Fredenslund’s consistency test. Based on the VLE results, this zeotropic binary mixture exhibits a positive deviation from Raoult’s law. Furthermore, the validated data are correlated with three activity coefficient models (i.e., Wilson, NRTL, and UNIQUAC), with the Wilson equation being the most accurate one. Excess volumes, surface tensions, and liquid viscosities data are correlated by Redlich–Kister-type expansions, and the Grunberg–Nissan equation is also applied to viscosity modeling. The calculated excess volumes display a positive deviation from the ideal solution model. Regarding surface tensions, this system showcases both negative and positive deviation, althouhg slight, from the linear behavior while exhibiting the linear trend at a molar fraction of methyl butyrate of 0.758. In addition, this bimodal deviation is adequately predicted by the Chunxi model with the Wilson parameters determined from the VLE data. Finally, the dynamic viscosities data obey a strictly monotonic mole dependence predicted by Eyring’s theory, although without high accuracy. These results also reflect some interesting phenomena related to competitive association effects, which are discussed.