Linear solvation energy relationships. Part 9.—Correlations of gas/liquid partition coefficients with the solvatochromic parameters, π*, α and β

Abstract

When referenced to an alkane solute of similar molecular volume, i.e. log (K_solute/K_alkane), gas/liquid partition coefficients for nitromethane, methylethylketone, dioxan, toluene and ethanol solutes are well correlated by the solvatochromic parameters, π*, δ, α and β. For nitromethane and dioxan solutes the partition coefficients depend only on the dipolarity/polarizability parameters (π*, δ). For methylethylketone, there is also a measurable dependence on hydrogen-bond donor acidity (α) of protic solvents. For ethanol in aliphatic non-hydrogen-bond donor solvents the dominant effects are solvent dipolarity/polarizability and solvent hydrogen-bond acceptor basicity (β). For toluene solute there appears to be a negative or desolvation effect in protic solvents which is attributed to a ‘hydroxyphobic effect’ of weakly basic solutes in alcohol solvents.