Phase equilibrium measurements and thermodynamic modeling of {CO2 + diethyl succinate + cosolvent} systems

Abstract

This work reports experimental phase equilibrium data for the binary systems {CO2(1) + diethyl succinate(2)} and {CO2(1) + ethyl acetate(2)}, and for the ternary systems {CO2(1) + diethyl succinate(2) + ethanol(3)} and {CO2(1) + diethyl succinate(2) + ethyl acetate(3)}.The experiments for the binary system {CO2(1) + diethyl succinate(2)} were carried out at temperatures ranging from 308 K to 358 K, and temperatures ranging from 303 K to 343 K for {CO2(1) + ethyl acetate(2)} as well as for all ternary systems. Only vapor-liquid equilibria were observed for all systems. The experimental measurements were carried out in a high-pressure variable-volume view cell containing a movable piston, which allows pressure control inside the cell. Binary and ternary systems were modeled with the Peng-Robinson cubic equation of state with the van der Waals quadratic mixing rule (vdW2).The presence of a cosolvent (ethanol and ethyl acetate) decreased the saturation pressures of either bubble or dew points compared to the binary system CO2 + diethyl succinate, increasing the solubility of diethyl succinate in CO2.

Phase-Equilibrium Measurements and Thermodynamic Modeling of CO2 + Geraniol, CO2 + Geraniol + Acetic Acid, and CO2 + Geraniol + Ethyl Acetate

“…Table summarizes all of the binary interaction parameters used or obtained in this work, where k ij represents the binary energy parameter, and l ij represents the repulsive energy parameter. CO 2 + ethyl acetate binary interaction parameters in the {CO 2 (1) + geraniol (2) + ethyl acetate (3)} ternary system were obtained from the study by Kloc et al Moreover, the binary interaction CO 2 + acetic acid was obtained by fitting the VLE presented by Bamberger et al The root-mean-square deviation (rmsd) was calculated using eq , where P cal, i and P exp, i represent, respectively, the saturation pressure calculated and obtained experimentally in the “ i ” measurement and NOBS, the number of experimental observations. When the binary interaction parameters were fixed for the binary system {CO 2 (1) + geraniol (2)}, the model did not accurately predict the phase behavior of this system. However, when these parameters are considered temperature-dependent, the PR model with the vdW2 mixing rule was capable of fitting well the complex phase behavior experimentally observed, including the prediction of VLE, LLE, and VLLE with a unique set of binary interaction parameters ( k 12 and l 12 ).…”

“… a Interaction parameters fitted using experimental data presented by Kloc et al b Interaction parameters fitted using VLE data presented by Bamberg et al …”

“…Table 7 summarizes all of the binary interaction parameters used or obtained in this work, where k ij represents the binary energy parameter, and l ij represents the repulsive energy parameter. CO 2 + ethyl acetate binary interaction parameters in the {CO 2 (1) + geraniol (2) + ethyl acetate (3)} ternary system were obtained from the study by Kloc et al 37 Moreover, the binary interaction CO 2 + acetic acid was obtained by fitting the VLE presented by Bamberger et al 38 The root-mean-square deviation (rmsd) was calculated using eq 4, where P cal,i and P exp,i represent, respectively, the saturation pressure calculated and obtained experimentally in the "i" measurement and NOBS, the number of experimental observations. P P rmsd ( )…”