Solvent Effects on Protonation Constants of benzohydroxamic acid in Different Aqueous Solutions of ۱- etanol

The protonation constants of benzohydroxamic acid have been determined in ۱۰–۸۰% (v/v) etanol-water mixtures at ۲۵ °C and constant ionic strength (۰.۱ mol L–۱ sodium perchlorate) by potentiometric technique and calculated using a suitable computer program which employs a nonlinear least- squares method. The effect of solvent composition on the protonation constants in the mixed solvents were correlated with the Kamlet-Taft solvatochromic parameters (a,B, and π*). It was shown that logK۱ and logK۲ values of benzohydroxamic acid increases with increasing etanol content up to ۵۰% and then tend to decrease. Further, more an over-view of the effect of preferential solvation and solvent structure of electrolytes in etanol-water mixtures on the values of the protonation constants in these media were also discussed. benzohydroxamic acid is determined in different aqueous solutions of ۱- etanol.

کلیدواژه ها:

Protonation constants ، benzohydroxamic acid ، etanol -water mixtures ، Kamlet-Taft Solvatochromic parameters ، Solvent Effect