载体对镍基催化剂催化氯代硝基苯加氢性能的影响

Influence of supporter on properties of nickel catalysts for hydrogenation of chloronitrobenzene to chloroaniline

分别以碳纳米管(CNTs)、SiO2、TiO2、γ-Al2O3、TiO2-SiO2、SiO2-TiO2和活性炭(AC)为载体,以Ni、B为活性组分,采用浸渍-化学还原法制备了一系列负载型Ni-B非晶态合金催化剂,采用了电感耦合等离子体光谱、X-射线衍射、透射电子显微镜、差示扫描量热等手段研究了催化剂的非晶性质、结构、粒子大小、Ni的担载量及催化剂的热稳定性。以3种氯代硝基苯液相加氢为目标反应,对各种催化剂的催化性能进行了评价。结果表明,负载型Ni-B非晶态合金催化剂在氯代硝基苯液相加氢反应中表现出较高的活性和良好的选择性,其中以CNTs为载体的非晶态合金Ni-B催化剂可使3种氯代硝基苯的转化率均高于99.8%,加氢脱氯率小于3%。讨论了CNTs和Ni-B非晶态合金之间的相互作用与催化剂的催化性能的关系。

The selective hydrogenation of chloronitrobenzene in the liquid-phase was studied with Ni-B amorphous alloy catalysts supported on CNTs,SiO2,TiO2,γ-Al2O3,TiO2-SiO2,SiO2-TiO2 and AC carriers prepared by the impregnation-chemical reduction method,using Ni-B as the active ingredient.The amount of support of the as-prepared Ni-B/CNTs catalyst was analyzed by ICP.Its amorphous alloy structure of the Ni-B/CNTs catalyst was confirmed by XRD.TEMwas used to determine its particle size,and the thermal stability of the Ni-B/CNTs catalyst was studied by DSC.The results showed that the Ni-B amorphous alloy catalyst supported on CNTs had higher catalytic performance than Ni-B and other Ni-based hydrogenation catalysts could be attributed to the unique structure of CNTs and the nature of amorphous metals on the surface of CNTs.The relationship between the interaction of CNTs and amorophous metals and the catalytic performance of the catalyst was discussed.The conversion of the three selected chloronitrobenzene all reached 99.9% and the dechlorination was less than 3%.