在邻氯硝基苯加氢制备邻氯苯胺的反应中,钯催化剂的催化活性高,但因易脱氯生成副产物苯胺,限制了钯催化剂在该工艺中的应用。综述了4类钯基催化剂在抑制脱氯副反应、提高选择性和转化率的研究进展。单钯催化剂的性能受纳米钯尺寸、载体性能和反应条件的影响较大;双、多金属钯基催化剂通过金属助剂的协同和增强效应提高了选择性;有机络合物钯基催化剂和非晶态钯基催化剂具有特别的潜能,但相关研究尚处在起步阶段。基于分析,展望了钯催化剂的研究方向。
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 aby-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.