Reduction of Aromatic Nitro Compounds Using Aluminium Scrap

Abstract

Reduction of aromatic nitro compounds with metals and concentrat¬ed acids have most commonly been carried out using iron, tin, zinc and magnesium metals. The acids used are H2SO4' HC1 and acetic acid. Astonishingly enough aluminium which is a cheaper metal than zinc, tin and magnesium has not been considered for this type of reduction. Only two references are cited in literature where aromatic nitro compounds have been reduced with aluminium in presence of dil H2SO4 to yield aminophenols [1,2]. In the present work reduction of same aromatic compounds with Al/conc.HC1 to obtain respective aniline is reported. Thus a cheaper reagent for the reduction of aromatic nitro compounds is introduced. Aluminium scrap has been used for the reduction and experiments were repeated by using aluminium powder (A.R. grade) for comparison of yields. The various anilines obtained were further characterized by preparing their derivatives (Table-II). The yields obtained with pure Al powder are about 5% higher than those obtained with Aluminium scrap. That may be due to the oxide layer on it which could not be fully removed. Nevertheless the yields obtained are high and compare favourably with those obtained by using magnesium, zinc or tin.