The kinetics of the reactions of picryl chloride with some substituted anilines. Part 6. 4-Substituted and 3,4-disubstituted anilines

Abstract

Arrhenius parameters have been measured for the reactions of picryl chloride with the following substituted anilines in acetonitrile: 4-X-(X = F, Cl, Br, I, Me, Or OMe); 3,4-X₂-(X = Cl, Br, Me, or OMe); 4-X-3-nitro-(X = F, Cl, or Me); 3-X-4-methoxy-(X = F, Cl, Br, or I); 3-fluoro-4-nitro-; and 3,4,5-trimethoxy-aniline. In the 3,4-disubstituted series the effect of two methyl groups on the free energy of activation is strictly additive, but for the rest the measured rate constants are greater than those calculated on the assumption of additivity. The results are rationalized in terms of the positions of the transition states on the reaction co-ordinate.