Kinetic studies of the reaction of some nitrosoalkanes with nitrogen dioxide

Abstract

The rates of the oxidation of some nitrosoalkanes (CH₃)₂C(CH₂X)NO by nitrogen dioxide in carbon tetrachloride have been studied by stopped-flow techniques, and have been found to exhibit second order kinetics. Arrhenius parameters have been determined for the cases of X = H, CH₃, C(CH₃)₃, C₆H₅, NO₂, Cl and OCOCH₃. Electron withdrawing substituents are found to decrease significantly the rates, which are generally much faster than the corresponding oxidation of nitrosoarenes. The results obtained are discussed with reference to the Hammett σ constants of the substituents X, and the atomic charges at the nitrogen atom as given by the TNDO/2 method, the geometries of the molecules having been optimised by the PM3 semi-empirical method.