MECHANISM OF REACTION OF AZOBENZENE FORMATION FROM ANILINE AND NITROSOBENZENE IN BASIC CONDITIONS - GENERAL BASE CATALYSIS BY HYDROXIDE ION

The reaction of nitrosobenzene with aniline, to give azobenzene, in basic conditions was studied. It was shown that the reaction exhibits general base catalysis by different buffers giving a Bronsted coefficient beta = 0.318. As in previous studies, a two-step process with a first step of attack of aniline on nitrosobenzene to give an addition intermediate and a second step of dehydration of this intermediate is proposed to interpret the mechanism of the reaction. The analysis of the Bronsted relationship and of the intermediate of the reaction led to the suggestion that hydoxide ion catalyses the reaction by a mechanism of general base catalysis in the dehydration step.