ABSTRACT
Aromatic haloamines have a wide range of applications in the production of pharmaceuticals and agrochemical substances. The main route to these haloanilines involves reduction from the corresponding nitro compounds either with group VIII metal catalysts and hydrogen or with iron and hydrochloric acid. Most of the time the reduction of halonitroaromatic to the corresponding amine is accompanied by simultaneous dehalogenation, which lowers the yield and results in the formation of corrosive halogen acids. The hydrogenations were carried out in a 500-mL Hastelloy autoclave stirred by a rotary Rushton turbine (1200 rpm) to perform the reactions at the gas-liquid mass-transfer limit; i.e., a further increase in agitation did not improve the rate of reaction. Raney nickel is a very attractive industrial catalyst because of its low cost compared to platinum. However, it is also well known to cause extensive dehalogenation during the hydrogenation of halonitroaromatics.
