Ni-B/SiO_2非晶态催化剂对卤代芳香硝基化合物的催化加氢性能

Catalytic hydrogenation of haloaromatic nitrocompounds on Ni-B/SiO_2 amorphous catalyst

对Ni-B/SiO2 非晶态催化剂在卤代芳香硝基化合物加氢制卤芳胺反应中的催化活性和选择性进行了研究。研究表明 ,该催化剂不仅具有很高的催化活性 ,且反应中卤芳胺脱卤率低 ,反应选择性高 ,寿命长 ,优于RaneyNi催化剂。晶化导致催化剂失活。载体能提高催化剂的分散度 ,使催化剂的活性比表面积增大。将催化剂保存在乙醇溶液中可保持其活性不变。通过催化剂的表征结果 ,讨论了Ni-B/SiO2非晶态催化剂及RaneyNi催化剂的催化活性与其机构的关系。

Ni-B/SiO_2 amorphous catalyst was employed in hydrogenation of haloaromatic nitrocompounds to haloaromaticamine.In comparison with other Ni-based catalysts,such as ultrafine Ni-B amorphous alloy,Raney Ni and the crystalline Ni-B/SiO_2,Ni-B/SiO_2 amorphous catalyst exhibited higher activity and better selectivity for haloaromaticamine.The catalyst could be kept in ethanol without significant decrease in the activity for a long period.The relationship between the catalytic activity and the nature of the active sites was discussed based on various characterizations including BET,SEM,XRD,etc.The silica support could disperse the catalyst,increased the surface active area of the catalyst.