Ni-B/SiO_2催化剂上硝基苯选择加氢制备苯胺

Selective Hydrogenation of Nitrobenzene to Aniline over Ni-B/SiO_2 Catalysts

以KBH4为还原剂,用浸渍-还原法制备了Ni-B/SiO2催化剂,并用于硝基苯催化加氢制苯胺的反应,讨论了制备条件(Ni、B用量及焙烧温度)及反应条件(压力、温度)对硝基苯的转化率及苯胺选择性的影响。结果表明,Ni-B/SiO2催化剂具有很高的催化活性。适当增加Ni和B的用量,可以提高催化剂对硝基苯的转化率和转化频率及苯胺的选择性。催化剂前驱体的焙烧温度在453K时,硝基苯的转化率可达到98·5%,对苯胺选择性为97·0%。过高的焙烧温度不利于催化剂活性的提高。适当提高加氢反应压力以及温度,可以提高催化剂的加氢活性及对苯胺的选择性。

Ni-B/SiO2 catalysts, which were prepared by impregnation-reduction with KBH4 as reductant, were used in the selective hydrogenation of nitrobenzene to aniline. The effects of factors, such as Ni dosage, B dosage, calcinations temperature, and reaction pressure and temperature, on the reaction were investigated. It was found that Ni-B/SiO2 catalysts exhibited good catalytic activities. With the suitable increase of the dosage of Ni and B, the conversion and TOF of nitrobenzene and the selectivity to aniline increased. When the precursor was calcined at 453 K, the conversion of nitrobenzene was 98. 5% and the selectivity to aniline was 97. 0 %. Higher calcinations temperature caused a decrease in activity. The suitable increase of reaction pressure and temperature resulted in higher activity and selectivity.