Additive effect of 1-propanol and 2-propanol on molecular organization of H2O in the water-rich region: Excess chemical potential, partial molar enthalpy and volume of 1-propanol in 1-propanol-2-propanol-H2O at 25 degrees C

Excess chemical potential, mu (E)(1P), partial molar enthalpy, H-1P(E) and volume of 1-propanol, V-1P(E), were determined as a function of mole fracti on of l-propanol, rip, in mixed solvents of aqueous 2-propanol with various initial mole fraction of 2-propanol, x(2P)(0). The 1-propanol-1-propanol i nteraction functions, H-1P-1P(E) equivalent to N(partial derivativeH(1P)(E) /partial derivativen(1P)), and V-1P-1P(E) equivalent to N(partial derivativ eV(1P)(E)/ partial derivativen(1P)), were evaluated by graphical differenti ation. The rip-dependence of all these quantities indicates that l-propanol and 2-propanol modify the molecular organization of H2O in the same and ad ditive manner in the water-rich region. The additive effect of 1-propanol a nd that of 2-propanol are in the ratio of (0.07/0.08).