THERMOCHEMICAL INVESTIGATIONS OF HYDROGEN-BONDED SOLUTIONS - DEVELOPMENT OF A PREDICTIVE EQUATION FOR THE SOLUBILITY OF ANTHRACENE IN BINARY HYDROCARBON PLUS ALCOHOL MIXTURES BASED UPON MOBILE ORDER THEORY

Experimental solubilities are reported for anthracene dissolved in twelve binary solvent mixtures containing either 2-propanol or 1-octanol with n-hexane, n-heptane, n-octane, cyclohexane, methylcyclohexane and 2,2,4-trimethylpentane at 25.0 degrees C. Results of these measurements, along with previously published solubility data for anthracene in binary 1-propanol + alkane and 1-butanol + alkane mixtures, are used to test the limitations and applications of expressions derived from Mobile Order theory. The best descriptive equation expresses the logarithm of the volume fraction solubility in binary mixtures as a simple volume fraction average of the corresponding logarithm solubilities in the two pure solvents, and contains additional terms to represent contributions from nonspecific physical interactions between dissimilar solvent components, from molecular size disparity, and from the reduction in mobile disorder caused by the self-association by hydrogen bonding of the alcohol solvent. The newly derived expression predicts the observed anthracene solubilities to within an overall average deviation of ca. 4.4% using a single value of K-C= 5000 for the self-association equilibrium constant.