SOLUTE SOLUTE INTERACTIONS AND THE KINETICS OF CHEMICAL-REACTIONS IN AQUEOUS-SOLUTIONS

Kinetics of chemical reactions involving substrates in aqueous solutions are examined from the standpoint of solute“-”water, solute“-”solute and solute-”cosolvent interactions. The rôle of water-”solute interactions is illustrated by contrasting isobaric and isochoric dependences of rate constants on temperature. The Savage-Wood treatment of group interactions between solutes in aqueous solutions provides a basis for treating the effects of added cosolutes on rate constants. Application of this treatment is illustrated using data describing kinetics of reactions involving organic and inorganic substrates. With increase in the amount of added solute/cosolvent, a better description is in terms of chemical reaction in binary mixed solvents. The dependence of rate constant on solvent composition is discussed in terms of preferential solvation of initial and transition states by either aqueous or nonaqueous components. The Inverse Kirkwood-Buff method offers an interesting approach for exploring these trends in solvent “-”solute interaction as a function of solvent composition. © 1990 De Gruyter