Ostwald solubility coefficients of 74 compounds in dry octan-1-ol at 298 K have been determined, and have been combined with literature values and additional values we have calculated from solubilities in dry octan-1-ol and vapour pressures to yield a total of 161 log LOctOH values at 298 K. These LOctOH values are identical to gas-to-dry octan-1-ol partition coefficients, often denoted as KOA. Application of the solvation equation of Abraham to 124 values as a training set yielded a correlation equation with n = 124, S.D. = 0.125, r2 = 0.9970 and F = 7731. This equation was then used to predict 32 values of log LOctOH as a test set, giving a standard deviation, S.D. of 0.131, an average absolute deviation of 0.085 and an average deviation of -0.009 log units. The solvation equation for the combined 156 log LOctOH values was logLOctOH = - 0.120 - 0.203R2 + 0.560π2H + 3.560 ∑ α2H + 0.702 ∑ β2H + 0.939logL16, n = 156, r2 = 0.9972, S.D. = 0.125, F =10573, where, n is the number of data points (solutes), r the correlation coefficient, S.D. the standard deviation and F is the F-statistic. The independent variables are solute descriptors as follows: R2 is an excess molar refraction, π2H the dipolarity/polarisability, ∑ α2H the overall or summation hydrogen-bond acidity, ∑ β2H the overall or summation hydrogen-bond basicity and L16 is the Ostwald solubility coefficient on hexadecane at 298 K. The equation is consistent with similar equations for the solubility of gases and vapours into methanol, ethanol and propan-1-ol. It is suggested that the equation can be used to predict further values of log LOctOH, for which the solute descriptors are known, to within 0.13 log units.
- Octanol-air partition