Improved models for the prediction of activity coefficients in nearly athermal mixtures .2. A theoretically-based G(E)-model based on the van der Waals partition function

Kontogeorgis, GM; Nikolopoulos, GI; Fredenslund, A; Tassios, DP

dc.contributor.author	Kontogeorgis, GM	en
dc.contributor.author	Nikolopoulos, GI	en
dc.contributor.author	Fredenslund, A	en
dc.contributor.author	Tassios, DP	en
dc.date.accessioned	2014-03-01T01:46:26Z
dc.date.available	2014-03-01T01:46:26Z
dc.date.issued	1997	en
dc.identifier.issn	0378-3812	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/24909
dc.subject	statistical mechanics	en
dc.subject	excess properties	en
dc.subject	alkane solutions	en
dc.subject	polymer solutions	en
dc.subject	free-volume	en
dc.subject.classification	Thermodynamics	en
dc.subject.classification	Chemistry, Physical	en
dc.subject.classification	Engineering, Chemical	en
dc.subject.other	VAPOR-LIQUID-EQUILIBRIA	en
dc.subject.other	CONTRIBUTION FLORY EQUATION	en
dc.subject.other	HARD-CHAIN THEORY	en
dc.subject.other	POLYMER-SOLUTIONS	en
dc.subject.other	PHASE-EQUILIBRIA	en
dc.subject.other	SOLVENT ACTIVITIES	en
dc.subject.other	CUBIC EQUATION	en
dc.subject.other	STATE	en
dc.subject.other	FLUIDS	en
dc.subject.other	SOLUBILITY	en
dc.title	Improved models for the prediction of activity coefficients in nearly athermal mixtures .2. A theoretically-based G(E)-model based on the van der Waals partition function	en
heal.type	journalArticle	en
heal.language	English	en
heal.publicationDate	1997	en
heal.abstract	This work, which is a continuation of a recent publication on the same topic (G.M. Kontogeorgis, P. Coutsikos, P. Tassios and Aa. Fredenslund, Fluid Phase Equilibria, 92 (1994) 35), presents a new theoretically-based G(E)-model (Chain-FV) for alkane systems. The model is based on a modified form of the generalized van der Waals partition function and attempts to account for all non-energetic effects of solutions of both short- and long-chain alkanes, including alkane polymers. Both the free-volume effects and the density-dependent rotational degrees of freedom are considered. The resulting G(E)-model which, despite its derivation from a partition function resembles the Flory-Huggins formula, is suitable for vapor-liquid and solid-liquid equilibrium calculations for nearly athermal polymer solutions as well as for alkane systems. We show that using plausible assumptions for the free-volume and the external-degree-of-freedom parameter, very good predictions are obtained for activity coefficients of asymmetric alkane systems at both concentration ends, for solid-liquid equilibrium calculations, as well as in extreme cases (polymer solutions, activity coefficients of heavy model alkane polymers in short-chain compounds recently available from molecular simulation studies). The predictions of the Chain-FV model are better than the Flory-Huggins and Elbro terms and equivalent to the recently proposed empirical R-UNIFAC and p-FV models. However, unlike the latter two models, the one proposed in this work offers a successful combination of simplicity and accuracy, with a solid theoretical basis.	en
heal.publisher	ELSEVIER SCIENCE BV	en
heal.journalName	FLUID PHASE EQUILIBRIA	en
dc.identifier.isi	ISI:A1997VZ98100007	en
dc.identifier.volume	127	en
dc.identifier.issue	1-2	en
dc.identifier.spage	103	en
dc.identifier.epage	121	en