RT Journal Article T1 Critical behavior and partial miscibility phenomena in binary mixtures of hydrocarbons by the statistical associating fluid theory A1 Jiménez Blas, Felipe A1 Vega, Lourdes F. AB Predictions of critical lines and partial miscibility of binary mixtures of hydrocarbons have been made by using a modified version of the statistical associating fluid theory (SAFT). The so-called soft-SAFT equation of state uses the Lennard-Jones potential for the reference fluid, instead of the hard-sphere potential of the original SAFT, accounting explicitly for the repulsive and dispersive forces in the reference term. The mixture behavior is predicted once an adequate set of molecular parameters (segment size, dispersive energy, and chain length) of the pure fluid is available. We use two sets of such parameters. The first set is obtained by fitting to the experimental saturated liquid density and by equating the chemical potential in the liquid and vapor phases for a range of temperatures and pressures. The second set is obtained from the previous one, by rescaling the segment size and dispersive energy to the experimental critical temperature and pressure. Results obtained from the theory with these parameters are compared to experimental results of hydrocarbon binary mixtures. The first set gives only qualitative agreement with experimental critical lines, although the general trend is correctly predicted. The agreement is excellent, however, when soft-SAFT is used with the rescaled molecular parameters, showing the ability of SAFT to quantitatively predict the behavior of mixtures. The equation is also able to predict transitions from complete to partial miscibility in binary mixtures containing methane. PB AIP Publishing SN 0021-9606 SN 1089-7690 (electronico) YR 1998 FD 1998 LK http://hdl.handle.net/10272/17278 UL http://hdl.handle.net/10272/17278 LA eng NO Jiménez Blas, F., Vega, L.F.: "Critical behavior and partial miscibility phenomena in binary mixtures of hydrocarbons by the statistical associating fluid theory". Journal of Chemical Physics. Vol. 109, n. 17, págs. 7405-7413, (1998). DOI 10.1063/1.477363 NO It is a pleasure to thank Dr. Allan D. Mackie, Dr. JosepBonet-A ´valos and Dr. Jorge Herna ´ndez-Cobos for helpfuldiscussions. This work was supported by DGICyT~PB96-1025!. One of us~F.J.B.!has a doctoral fellowship fromComisionat per a Universitats i Recerca from the Generalitatde Catalunya. The financial support of this fellowship isgratefully acknowledged. DS Repositorio Institucional de la Universidad de Huelva RD 1 jun 2026