Abstract
The rate constants for the reaction of 2,6-bis(trifluoromethanesulfonyl)-4-nitroanisole with some substituted anilines have been measured by spectrophotometric methods in methanol at various temperatures. The data are consistent with the SNAr mechanism. The effect of substituents on the rate of reaction has been examined. Good linear relationships were obtained from the plots of log k(1) against Hammett sigma(para) constants values at all temperature with negative rho values (-1.68 to -1.11). Activation parameters Delta H-not equal varied from 41.6 to 54.3 kJ mol(-1) and Delta S-not equal from -142.7 to -114,6 1 mol(-1) K-1. The delta Delta H-not equal and delta Delta S-not equal reaction constants were determined from the dependence of Delta H-not equal and Delta S-not equal activation parameters on the sigma substituent constants, by analogy with the Hammett equation. A plot of Delta H-not equal versus Delta S-not equal for the reaction gave good straight line with 177 degrees C isokinetic temperature. (C) 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 203-210, 2010