Deactivation of Ni/K2O-La2O3-SiO2 catalyst in hydrogenation of m-dinitrobenzene to m-phenylenediamine
Deactivation of Ni/K2O-La2O3-SiO2 catalyst in hydrogenation of m-dinitrobenzene to m-phenylenediamine
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DOI：
10.1016/j.molcata.2005.11.003
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发表时间：
2006-03
影响因子：
--
通讯作者：
Lei Zhao;Jixiang Chen;Jiyan Zhang
中科院分区：
文献类型：
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作者：
Lei Zhao;Jixiang Chen;Jiyan Zhang
制备了一种新型负载型镍基催化剂Ni/K2 O-La 2 O3-SiO2，并考察了其在间二硝基苯催化加氢制间苯二胺反应中的稳定性和失活情况。以乙醇为溶剂，在373 K、3.0MPa、催化剂/间二硝基苯质量比为3%、溶剂/间二硝基苯质量比为2的反应条件下，间二硝基苯的转化率为99.9%，间苯二胺的选择性大于99.6%。采用N2吸附-脱附、X射线衍射（XRD）、热重/差热分析（TGA/DTA）、扫描电镜（SEM）和原子吸收光谱（AAS）等手段对反应前后的催化剂进行了表征。结果表明，催化剂失活的主要原因是大分子物种的表面覆盖和孔堵塞。此外，活性组分镍的损失也会在一定程度上导致催化剂失活。
A novel supported nickel-based catalyst, Ni/K2O-La2O3-SiO2, was prepared and its catalytic stability and deactivation in the catalytic hydrogenation of m-dinitrobenzene to m-phenylenediamine were investigated. With ethanol as solvent, under the reaction conditions of 373K, 3.0MPa, catalyst/m-dinitrobenzene mass ratio of 3% and solvent/m-dinitrobenzene mass ratio of 2, the conversion of m-dinitrobenzene and the selectivity of m-phenylenediamine were 99.9% and over 99.6%, respectively. There was a trend of catalyst deactivation during recycles and the catalysts before and after reaction were characterized by means of N2adsorption–desorption, X-ray diffraction (XRD), thermogravimetric analysis (TGA)/differential thermal analysis (DTA), scanning electron microscopy (SEM) and atomic absorption spectrometry (AAS). The results indicated that the catalyst deactivation could be mainly ascribed to the surface coverage and the pore blockage with bulky molecular species. Additionally, the loss of active component nickel could also result in the catalyst deactivation to some extent.