Kinetic solvent effects on reaction rates for the acidic hydrolysis of dihydroxamic acid

Kinetic solvent effects on a key A-Ac-2 type reaction, i.e,, acidic hydrolysis of succinodihydroxamic acid in aqueous mixtures (10-80% v/v) of some protic cosolvents viz methanol, ethanol, propan-2-ol and aprotic cosolvents viz 1,4-dioxane, acetonitrile, dimethyl sulphoxide, acetone, dimethylformamide have been analysed in the light of solvation energetics of the initial state and transition state. The observed log k(psi) - solvent composition profiles reveal that the rate increases with increasing percentage of solvents. Linear solvation energy relationships and solvatochromic parameters (alpha, beta, pi*), effects of dielectric constant and E-T have been applied to quantity solvent effects on reaction rates. The thermodynamic parameters (DeltaHdouble dagger and DeltaSdouble dagger) are sensitive to the structural changes in the bulk solvent phase.