AUTOPROTOLYSIS IN AQUEOUS-ORGANIC SOLVENT MIXTURES

The primary chemical equilibria which define autoprotolysis in aqueous binary solvents have been elucidated and the constants of these equilibria computed for aqueous solvent mixtures of methanol, ethanol, 1-propanol, 2-propanol, 2-methyl-2-propanol, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2,3-propanetriol, acetonitrile, acetone, tetrahydrofuran, dimethyl sulfoxide, 1,4-dioxane, and formic acid. The values of these constants explain the different behaviors of the diverse binary solvents. From these fundamental constants, the pK(ap) value at any solvent composition of any of the binary solvents studied can be accurately computed. It is also demonstrated that in most parts of the ranges of solvent compositions of binary solvents, autoprotolysis is mainly performed by proton transfer from water to the organic solvent.