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

A conventional non-electrolyte self-associated solution model, which h as led to successful descriptive equations for excess molar enthalpies and excess molar Gibbs free energies, is extended to systems containi ng an inert solute dissolved in binary hydrocarbon + alcohol solvent m ixtures. An expression is derived for predicting the solubility of cry stalline solutes from a prior knowledge of the solubility in the two p ure solvents. Applications and limitations of the newly derived equati on 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 app roximately 9.4 % using zero adjustable ''curve-fit'' parameters. Mobil e Order theory, in comparison, provides slightly superior predictions, with deviations between predicted and experimental values being in th e order of approximately 5.7%.