Mercuric salt catalyzed nitration of toluene

Abstract

The mercuric acetate catalyzed nitration of toluene in acetic acid at 80 °C produces 36% 2-, 12% 3-, and 52% 4-nitrotoluene. Other soluble mercury compounds produce similar results. Under these conditions, toluene is 6.1-fold more reactive than benzene. The reaction of 4-deuteriotoluene proceeds with a primary kinetic isotope effect of 3.1. 4-Tolylmercuric acetate reacts with nitric acid under these conditions to yield 4-nitrotoluene rapidly and quantitatively. The addition of urea to the reaction mixture inhibits the catalyzed nitration reaction and the reaction of 4tolylmercuric acetate with nitric acid. The mercuration of toluene is not inhibited by urea. 4-Tolylmercuric acetate reacts with nitrosation agents to yield 4-nitrosotoluene and with nitration reagents to yield 3-nitro-4-methylphenylmercuric acetate. These results indicate that the reaction occurs in three steps: mercuration, nitrosodemercuration (rather than nitrodemercuration), and oxidation of nitrosotoluene to nitrotoluene. The relative rate and product distribution are determined in the initial mercuration reaction.