THERMOCHEMICAL INVESTIGATIONS OF HYDROGEN-BONDED SOLUTIONS .2. COMPARISON OF MOBILE ORDER THEORY VERSUS MECKE-KEMPTER ASSOCIATION MODEL FOR DESCRIBING ANTHRACENE SOLUBILITIES IN BINARY HYDROCARBON PLUS ALCOHOL SOLVENT MIXTURES

A conventional non-electrolyte self-associated solution model, which has led to successful descriptive equations for excess molar enthalpies and excess molar Gibbs free energies, is extended to systems containing an inert solute dissolved in binary hydrocarbon + alcohol solvent mixtures. An expression is derived for predicting the solubility of crystalline solutes from a prior knowledge of the solubility in the two pure solvents. Applications and limitations of the newly derived equation were assessed using published solubility data for anthracene in 30 different binary solvent systems containing 1-propanol, 2-propanol, 1-butanol, 2-butanol or 1-octanol. The derived expression predicted the observed values to within an overall average absolute deviation of approximately 9.4 % using zero adjustable ''curve-fit'' parameters. Mobile Order theory, in comparison, provides slightly superior predictions, with deviations between predicted and experimental values being in the order of approximately 5.7%.