Nitrosation of aniline by N2O4

Abstract

Kinetics of nitrosation of aniline by N₂O₄ in donor non-aqueous solvents, e.g. acetonitrile, ethylacetate and a 1:1 v/v mixture of both, have been studied. The reaction is first-order with respect to N₂O₄ and zero-order with respect to aniline in each of the donor solvents added. The average observed order of k values is ethylacetate (7.195 × 10^–3) > acetonitrile (4.773 × 10^–3) > 1.1 v/v acetonitrile + ethylacetate mixture (3.216 × 10^–3 s^–1).

The variation of k values in the different solvents is interpreted in terms of solvation ability of the solvents. Conductivity measurements and u.v. studies of N₂O₄ solutions are reported. Both the initial and integral rate methods show that the rate-determining step is the one which involves the formation of the nitrosating agent, NO⁺, from N₂O₄. Accordingly a mechanism of nitrosation is proposed.