Free energy of some organic substances in organic solvents
(1) x rapid and reliable method has been devised for the determination of the energy transfer of a solute from the dilute vapour (ter log p /N) or pure liquid (i.AT log p /p °N) to a dilute solution.(2) The partial vapour pressures at low concen- trations of four lower aliphatic alcohols, some derivatives, and a few other organic compounds have been determined in benzene at 25 °.(3) Similar determinations have been made in carbon tetrachloride.(4) with the exception of the alcohols, similar determinations have been made in cyclo hexane.(5) The energies of solvation (RT log p /N) and dilution (RP log p /p °N) have been calculated for the solutes in benzene, carbon tetrachloride and cyclo hexane.(6) The advantage of using values of i1 log p/N as against AT log p /p °N, for theoretical consider- ations, is demonstrated by the regularity of these values, shown in the Tables, compared with the erratic figures for tir log p /p °N.(7) The results are interpretated in terms of Hildebrand's internal pressure theory, and show agreement with a semi -quantitative equation, based on London's equation for the mutual potential of two atoms, and Langmuir's theory of independent surface action, derived by Butler (unpublished).