Oxidation of aniline over transition metal — Substituted zeolites

Abstract

Abstract The oxidation of aniline was carried out in the liquid phase over a series of transition metal — substituted molecular sieves. For low oxidant/aniline ratios, azoxybenzene (AZY) was the major product formed over Ti-containing catalysts. the reaction was limited by diffusion for medium pore zeolites like TS-1 and mesoporous silicas were preferred as they permitted the use of both H 2 O 2 and tert-butyl hydroperoxide as oxidants. Higher oxidant/aniline ratios (>2) led to the formation of nitrobenzene (NB), whose selectivity was proportional to the catalyst concentration. In contrast, vanadium containing molecular sieves were only active with TBHP and aniline was converted very selectively into nitrobenzene for all oxidant concentrations.