非晶态合金NiB/Al_2O_3催化对氯硝基苯液相加氢制备对氯苯胺

HYDROGENATION OF p-CHLORONITROBENZENE TO p-CHLOROANILINE OVER AMORPHOUS NiB/Al_2O_3 CATALYST

采用浸渍-还原法制备了非晶态NiB/Al2O3催化剂,考察非晶态NiB/Al2O3催化剂对对氯硝基苯液相加氢制备对氯苯胺的催化性能。研究了Ni负载量、反应温度、反应压力对对氯硝基苯加氢反应性能的影响。结果表明:当催化剂中Ni负载量为20%、反应温度348K、反应压力1.2 MPa时,对氯硝基苯的转化率达到100%,对氯苯胺的选择性高于97%;催化剂重复使用6次,催化活性基本不变。采用XRD、BET、DTA、SEM等方法对催化剂进行了表征,结果表明:非晶态NiB/Al2O3催化剂具有高催化活性是由于载体的引入不仅提高了催化剂的分散度,防止超细NiB聚集,而且能够提高非晶态结构的热稳定性。

Supported amorphous NiB/Al2O3 alloy catalysts were prepared by impregnation-chemical re- duction method and their catalytic activity was studied for liquid-phase hydrogenation of p-chloronitro- benzene to p-chloroaniline. The effects of Ni-loading, reaction temperature and pressure on the hydro- genation performance of catalysts were investigated and the results showed that p-chloroaniline was obtained in 97% with complete conversion of p-chloronitrobenzene at 20% Ni-loading, 348 K and 1.2 MPa. The catalytic activity of NiB/Al2O3 catalyst kept almost the same after reusing for 6 times. The samples were characterized by XRD,BET,DTA and SEM. The results suggested that NiB/Al2O3 cat- alyst exhibited the highly catalytic activity due to the improved dispersion of the active component NiB, the supressed agglomerate of NiB particles and also the promoted thermostability of NiB amor- phous structures as the ultrafine NiB supported on Al2O3.