Experimental determination of the critical loci for {n-C6H14 or CO2 + alkan-1-ol} mixtures. Evaluation of their critical and subcritical behavior using PC-SAFT EoS

Abstract

Vapor–liquid critical locus (x, Tc, Pc) has been determined, in the whole range of mole fractions, for the systems {n-hexane+methanol, or +ethanol, or +propan-1-ol, or +butan-1-ol} and {CO2+methanol, or +ethanol, or +propan-1-ol, or +butan-1-ol}.A comprehensive bibliographic review for the vapor–liquid equilibrium (VLE) and the critical locus of these systems has been performed, and they have been modelled with PC-SAFT EoS. The three parameters that characterize the segments of pure compounds have been rescaled from their critical point values. In all cases, the classical mixing rules and temperature-dependent binary interaction parameters kij(T)=kij0+kij1T have been used.The average deviations obtained for the n-hexane+alkan-1-ol binary mixtures are: for critical loci, mean relative deviation in critical temperature MRD(Tc)=0.47% and in critical pressure MRD(Pc)=3.38%; for VLE, mean relative deviation in bubble pressure MRD(P)=2.90% and absolute deviation for the solvent mole fraction in the vapor phase ΔyC6H14=0.031.The average deviations obtained for the CO2+alkan-1-ol binary mixtures are MRD(Tc)=1.91% and MRD(Pc)=5.93%; MRD(P)=7.07% and ΔyCO2=0.022.