The kinetics of the reactions of picryl chloride with some substituted anilines. Part 5

Abstract

Arrhenius parameters have been measured for the reactions of picryl chloride with the following substituted anilines in acetonitrile: 3-amino- and 3-methyl-aniline, 3-amino-5-nitroaniline, 3-fluoro-5-methylsulphonyl-aniline, 3-X-5-methylanilines (X = NO₂, OMe, CH₃, F, Cl, Br, or I) and 3,5-X₂-anilines (X = F, Cl, Br, or I). A total of 33 3,5-disubstituted anilines have now been examined for the additivity of substituent effects on the free energy of activation, and it has been shown that with the exception of 3-amino-5-nitroaniline this hypothesis reproduces experimental rate constants within a factor of 2. A rationalization is proposed for the deviations that occur in some cases when more stringent criteria of additivity are used.