Ž . Fluid Phase Equilibria 142 1998 33–54 Group contribution equation of state based on the lattice fluid theory: Alkane–alkanol systems 1 Silvana Mattedi a,2 , Frederico W. Tavares b, ) , Marcelo Castier b a Programa de Engenharia Quımica – COPPE, UniÕersidade Federal do Rio de Janeiro, C.P. 68502, Rio de Janeiro, ´ Rio de Janeiro, CEP-21949-970, Brazil b Escola de Quımica, UniÕersidade Federal do Rio de Janeiro, C.P. 68542, Rio de Janeiro, Rio de Janeiro, ´ CEP-21949-900, Brazil Received 7 April 1997; accepted 24 August 1997 Abstract Ž . A new group-contribution equation of state EOS is proposed and applied to phase equilibrium calculations. The EOS is based on the generalized van der Waals theory and combines the Staverman–Guggenheim combinatorial term of lattice statistics with an attractive lattice gas expression. The EOS is applied to Ž . vapor–liquid equilibrium VLE calculations in systems containing pure hydrocarbons, alcohols, and their binary mixtures. These systems cover a wide range of situations, including nonpolar and polar compounds of different sizes and mixtures ranging from nearly-ideal to azeotropic behavior. Using VLE data for pure Ž . substances and binary mixtures of linear hydrocarbons, the parameters of linear alkane groups CH and CH 3 2 were simultaneously fitted. For pure linear alkanes up to C , calculated vapor pressures deviate less than 1.7% 12 Ž . from the experimental values. Predicted vapor pressures of eight heavy hydrocarbons from C to C are in 14 28 Ž satisfactory agreement with experimental data. The parameters for other groups branched alkanes and alcohol . groups were fitted sequentially, using data for pure compounds and binary mixtures only containing the characteristic group being estimated and linear alkane groups. Satisfactory predictions of the vapor pressures of pure substances and bubble pressures of binary mixtures were obtained. q 1998 Elsevier Science B.V. Keywords: Theory; Equation of state; Group contribution; Alkanes; Alkanols 1. Introduction The development and application of group-contribution thermodynamic models have been the subject of numerous studies in the last decades, as shown in the reviews of Fredenslund and Sørensen ) Corresponding author. 1 Presented at the session in honor of Prof. Aage Fredenslund, AIChE Spring Meeting, Houston, 1997. 2 Laboratorio de Energia, DEQ-Escola Politecnica, Universidade Federal da Bahia, Brazil. ´ ´ 0378-3812r98r$19.00 q 1998 Elsevier Science B.V. All rights reserved. Ž . PII S0378-3812 97 00218-5