Brian G. Gowenlock, Boyd King, Josef Pfab and Michal Witanowski
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.