工业放大碳包覆镍催化剂在催化加氢芳硝基化合物中的应用

Industrial production of carbon encapsulated Ni catalyst for selective hydrogenation of nitroaromatics

基于金属羧酸络合物前体热解法,实现碳包覆镍(Ni@C)纳米复合材料的工业放大生产。考察了Ni@C催化剂在芳硝基化合物选择性加氢反应中的性能,通过分析加氢反应的中间产物并以苯基羟胺为模型化合物开展加氢评价及循环套用实验。实验结果表明,Ni@C可在温和的反应条件下(50℃,1 MPa H_(2))高选择性(高于99%)加氢4-硝基氯苯(4-NCB)、4-硝基苯酚、1,3-二硝基苯等多种芳硝基化合物,合成对应的芳香胺类化合物;Ni@C催化加氢4-NCB的过程为直接路径与缩合路径并存的反应路径,且Ni@C催化剂具有较好的稳定性;Ni@C还具有抗噻吩等硫化物中毒的特性,并可用于硫代芳胺的合成。

Industrial production of carbon encapsulated Ni(Ni@C)is successfully achieved through pyrolysis the precursor of metal carboxylic acid complexes.The performance of Ni@C in the catalytic hydrogenation of nitroaromatics was evaluated.The Ni@C catalyst demonstrates excellent selectivity(greater than 99%)for the hydrogenation of nitroaromatics such as 4-nitrochlorobenzene(4-NCB),4-nitrophenol,and 1,3-dinitrobenzene towards corresponding anilines under a mild condition(50℃,H_(2) at 1 MPa).By analyzing the intermediate products and using phenylhydroxylamine as a model compound,it is identified that the hydrogenation of 4-NCB over Ni@C follows both direct and condensation pathways.Besides,Ni@C shows good reusability without the loss of its activity.In addition,it exhibits anti-sulfur(thiophene)poisoning capability and can be used for the hydrogenation of thioanilines.