Solubility in binary solvent systems I: Specific versus nonspecific interactions

J Pharm Sci. 1982 Feb;71(2):201-5. doi: 10.1002/jps.2600710216.


Solubilities are reported for benzil in carbon tetrachloride-alkane (isooctane, n-octane, cyclooctane) systems at 25 degrees and in similar binary mixtures containing cyclohexane plus alkane. The results of these measurements are compared to solution models previously developed for solubility in systems containing specific solute-solvent interactions and to models for purely nonspecific interactions. A stoichiometric complexation model based primarily on specific solute-solvent interactions requires several equilibrium constants to mathematically describe the experimental solubilities in binary carbon tetrachloride mixtures. However, there was no direct experimental evidence to suggest complexation between benzil and carbon tetrachloride. In comparison, expressions derived from the Nearly Ideal Binary Solvent (NIBS) model for nonspecific interactions predict experimental solubilities with a maximum deviation of 5% and an overall deviation of 1.0%. The success of the NIBS approach for this system is significant because the mole fraction solubility of benzil changes by a factor of 14 in the carbon tetrachloride-isooctane system.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alkanes
  • Carbon Tetrachloride
  • Chemistry, Pharmaceutical*
  • Models, Chemical
  • Phenylglyoxal / analogs & derivatives
  • Solubility*
  • Solvents


  • Alkanes
  • Solvents
  • Carbon Tetrachloride
  • Phenylglyoxal
  • benzil