CHARACTERISTIC PARAMETERS OF THE TASSIOS, LARSEN AND GMEHLING VERSIONS OF THE UNIFAC MODEL FOR ENTHALPIES OF MIXING IN ORGANIC ANHYDRIDES PLUS N-ALKANES MIXTURES

The characteristic parameters for the Tassios et al. (Ind. Eng. Chem. Process Des. Dev. 23 (1984) 391; 24 (1985) 701; 25 (1986) 22), Larsen et al. (Ind. Eng. Chem. Res. 26 (1987) 2274), and Gmehling et al. (Ibi d. 32 (1993) 178) versions of UNIFAC model for organic anhydrides + n- alkane systems have been calculated. For the first time, published dat a on excess enthalpies have been used to estimate the interaction para meters between the anhydride group CO-O-CO and the methyl and methylen e groups (CH3 and CH2), respectively. In the case of the Gmehling vers ion, the geometrical parameters of the anhydride group are also determ ined. The mean deviations for the excess enthalpies were about 2% for all versions. We have also compared our results with those obtained by Kehiaian et al. (Fluid Phase Equilibria 69 (1991) 91) with the DISQUA C model. (C) 1998 Published by Elsevier Science B.V.