Solvent and substituent effects on the reaction of 2‐ and 4‐chloro‐3,5‐dinitrobenzotrifluorides with substituted anilines

The solvent effect on a nucleophilic substitution reaction of 2‐ and 4‐chloro‐3,5‐dinitrobenzotrifluoride with substituted anilines was studied in methanol, acetonitrile, and toluene at 25°C. This reaction is of second order, except 2‐chloro‐3,5‐dinitrobenzotrifluoride in toluene shows third order. The k A values are found to be dependent on the substituent in aniline and give good Hammett correlations. The obtained ρ values are −4.07 and −4.62, for the reaction of anilines with 2‐chloro‐3,5‐dinitrobenzotrifluoride in methanol and acetonitrile, respectively. The ρ values for the reaction of the anilines with 4‐chloro‐3,5‐dinitrobenzotrifluoride are −3.38, −4.11, and −4.34 in methanol, acetonitrile, and toluene, respectively. The reaction of the former compound with anilines in toluene shows a second order in aniline. The dependence of the reaction on the external base such as DABCO suggests a proton transfer controlling step. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 777–786, 2009