Solid-liquid equilibria (SLE) for solvent-triachylglyceride (TAG) systems are studeid with activity coefficient models. Systems consisted of 29 data sets of C10:0 to C18:0 saturated triglycerides in nine solvents, benzene, acetone, carbon disulfide, carbon tetrachloride, chloroform, diethyl ether, ethanol, ethyl acetate, and n-hexane making up 562 data points. Eighteen activity coefficient models containing 0-2 fitting parametrs were evaluated including a number of Flory Free Volume (FFV) and Entropic Free Volume (FEFV) models evaluated by Coutinho et al. [J.A.P. Coutinho, S.I. Andersen, E.H. Stenby, Evaluation of activity coefficient models in prediction of alkane-solid liquid equilbria, Fluid Phase Equilibria 103 (1995) 23-39}, the UNIFAC model and its variations, the Wilson, UNIQUAC, and Van Laar equations and some proposed modifications of the FEFV and UNIFAC models. The modifications were as follows: (i) a Flory type parameter was added to the FEFV model (FEFV-X) and (ii) the exponent in the UNIFAC combinatorial term was treated as a fitting temperature. The best predictive model for TAG-solvent systems was found to be the Dortmund version of UNIFAC. Addition of a fitting parameter to the UNIFAC models provided significant improvement. For the UNIFAC-1977, UNIFAC (Lyngby) and UNIFAC (Dortmund), these exponents were found to be 0.897, 0.858, and 0.749, respectively. The best single parameter correlative model was found to be the FEFV-X model, which gave an AAPD of 0.305%. The Wilson equation was the best two parameter correlation equation and provided an AAPD of 0.154%.
ASJC Scopus subject areas
- Chemical Engineering(all)
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry