Iwai, Y., Yamamoto, H., Shimizu, T. and Arai, Y., 1990. Correlation of solubilities of coal liquefaction products in supercritical carbon dioxide and solubility enhancements using equation of state. The solubility behavior in the supercritical region is essentially important in process design of supercritical fluid extraction. An entrainer is often used to enhance the solubilities of high boiling components in the gas phase. The cubic equation of state having three constants, recently proposed by Yu et al., was applied to correlate the solubilities of coal liquefaction products (solid components) in supercritical CO2 and the solubility enhancements by entrainers. Conventional mixing rules were adopted for calculation of cross factors aij, bij, and cij. Binary parameters kij for calculation of aij, and lij for bij and cij were used. The binary parameters kij and lij (i.e. cross factors aij, bij, and cij) were determined to represent well the solubility data. Further, they were correlated with pure component properties of supercritical CO2 and solid components such as critical volume, solid volume, number of atoms in molecule except for hydrogen, and solubility parameter. By using the empirical equations for calculation of the binary parameters kij and lij, the solubilities of solid components in supercritical CO2 were calculated with good accuracy.