Dissociation equilibrium of nitroform in mixtures of polar solvents studied by pulse radiolysis

The dissociation equilibrium C(NO2)3H ⇌ C(NO2)–3+ H+sol and the related kinetics have been studied for mixtures of polar solvents. The dissociation constant is found to be essentially controlled by the rate constant for the neutralization of nitroform anions by solvated protons. An almost linear dependence of the pK of nitroform on the solvent composition is observed for t-butanol-ethylene glycol mixtures. With water as one of the solvent components, a different effect on the dissociation constant is noted and the pK value rapidly attains that for pure water. In mixtures of acetone and alcohols the pK against solvent composition curve goes through a minimum. The results are discussed on the basis of the neutralization kinetics of the nitroform anion.