NiB/SiO_2非晶态催化剂应用于硝基苯液相加氢制苯胺  

Liquid-Phase Hydrogenation of Nitrobenzene to Aniline over Ni-B/SiO_2 Amorphous Catalyst

作　　者：王明辉[1] 李和兴[1] 

机构地区：[1]上海师范大学化学系,上海200234

出　　处：《催化学报》2001年第3期287-290,共4页

基　　金：国家自然科学基金!(2 99730 2 5 );上海市教委发展基金!(99D12 )资助项目

摘　　要：考察了Ni B/SiO2 非晶态催化剂在高压液相硝基苯加氢制苯胺反应中的催化活性和选择性 .研究表明 ,该催化剂不仅具有很高的催化活性 ,而且对苯胺的选择性较高 ,优于RaneyNi以及其它Ni基催化剂 .晶化导致催化剂失活 .载体的存在不仅能提高催化剂的分散度 ,而且能对非晶态结构起稳定化作用 ;将催化剂保存在乙醇中可保持其活性不变 .结合催化剂的表征 ,讨论了Ni B/SiO2A Ni-B/SiO2 amorphous catalyst, prepared by impregnation of silica support with Ni ions which were reduced by KBH4 aqueous solution, was employed in liquid-phase hydrogenation of nitrobenzene to ani-line. In comparison with other Ni-based catalysts, such as ultrafine Ni-B amorphous alloy, Raney Ni, Ni/SiO2 and the crystalline Ni-B/SiO2, the as-prepared Ni-B/SiO2 amorphous catalyst exhibited higher activity and better selectivity for aniline. The catalyst could be kept in ethanol without significant decrease in the activity for a long period. However, deactivation of the catalyst was observed when it was crystallized at high temperature. The relationship between the catalytic activity and the nature of the active sites was discussed based on various characterizations including BET, SEM, XRD, XPS, hydrogen chemisorption, etc. The higher activity of the Ni-B/SiO2 amorphous catalyst could be attributed to the higher dispersion of the Ni active sites. and was closely related to both the structural and electronic effects on the catalytic property of the Ni active sites. The promoting effect of the silica support was interpreted in terms of its dispersing effect which increased the surface active area of the catalyst on one hand and inhibited the crystallization of Ni-B amorphous alloy on the other.

关 键 词：镍 硼 二氧化硅 负载型非晶态催化剂 硝基苯 催化加氢 苯胺 催化活性 结构 

分 类 号：O643.3[理学—物理化学]