| Palladium catalysts have high catalytic activity in the synthesis of o-chloroaniline from o-chloro- nitrobenzene. However, their application in the synthetic process is largely compromised by a by-product, aniline, formed during the hydrogenation of o-chloronitrobenzene on palladium. The progress recently made in the inhibition of dechlorination reaction, the improvement of selectivity and the conversion rate was reviewed in the present paper. The performance of mono-palladium catalyst is influenced by the size of palladium, carrier profile and reaction conditions. Double, polymetallic palladium-based catalysts improve the selectivity through the synergistic and enhancing effects of metal promoters. Organic palladium complexes and amorphous palladium-based catalysts have potential for catalyzing hydrogenation of o-chloronitrobenzene, but are still in the initial stage of development. Based on the analysis, the research direction of the palladium catalysts was prospected. |
