Determining sublimation pressures from solubility data of solids in different solvents

Solvent effects in the calculation of the sublimation pressure of pure solids using high pressure solubility data are discussed. Three binary gas–solid systems containing anthracene, napthalene and phenanthrene as solutes and carbon dioxide, ethane, ethylene, fluoroform, chlorotrifluoromethane as solvents are considered in the study. The Peng–Robinson EoS with the mixing rules proposed by Wong and Sandler are used to evaluate the fugacity coefficient φS included in the classical solubility equation which relates the mole fraction of a dissolved solid in a compressed gas phase. The sublimation pressure PS of the solid is considered as a parameter to be determined by regression analysis of experimental solubility data (TPy), and theoretically it should be independent of the solvent. The results show that the determination of sublimation pressure using high pressure solubility data is reliable and produce unique values of sublimation pressure independent of the solvents in the mixtures.