Calculation of autoprotolysis constants and solvent effect using AB Initio method for water-ethanol mixture

The autoprotolysis constants (pKap) of water-ethanol mixtures containing 10-90 % v/v of ethanol have been measured at 298.15 K using ab initio and density functional theory (DFT) methods. Basis sets at the B3LYP/6-31+G(d) level of theory were used for calculations. These data show that water-ethanol mixtures are more basic media than pure water and the pKap value of this media increases with addition of ethanol. The effect of the dielectric constant of investigated mixture solvent on the autoprotolysis constant was described employing Yasuda-Shedlovsky procedure.