非晶态Ni-M-P催化剂用于间氯硝基苯加氢的研究

Liquid-Phase Hydrogenation of m-Chloronitrobenzene over Ni-M-P Amorphous Alloy Catalyst

采用化学还原法制备了Ni-M-P(M=Cu,Ca,Zn,Sn,Co)非晶态合金催化剂,用X射线能谱(EDS)、X射线衍射(XRD)和透射电子显微镜(TEM)等方法对催化剂的组成、结构及形貌进行了表征,以间氯硝基苯液相催化加氢合成间氯苯胺为目标反应,对所制备催化剂性能进行系统评价,以解决催化加氢合成间氯苯胺过程中的氢解脱卤问题。研究结果表明,在所制备的三元非晶态合金催化剂中,在不加脱卤抑制剂的情况下,反应温度110℃、氢气压力1.0MPa的反应条件下,当Ni:Co=1:1(摩尔比)时,Ni-Co-P表现出较高的加氢性能和抑制脱卤性能,间氯硝基苯的转化率可达到99.0%,间氯苯胺的选择性也达到了99.3%,其转化率和选择性较其它三元催化剂和Ni-P催化剂有较大提高。从催化剂的微观结构和电子效应等方面讨论和解释了添加第三组分金属对Ni-P非晶态合金催化剂催化性能的影响。

In order to solve the problem of occurring hydrodechlorination during the hydrogenation process of m-chloronitrobenzene, the Ni-M-P （M = Cu, Ca, Zn, Sn, Co） amorphous alloy catalysts were prepared by the chemical reduction method. It is shown that the introduction of the third metal component M into Ni-P catalyst has a significant influence on the catalytic properties, and the experiments show that during the hydrogenation of m- chloronitrobenzene, among all the Ni-M-P catalysts prepared, the Ni-Co-P catalyst has a higher catalytic activity and selectivity than other Ni-M-P catalysts prepared and even the Ni-P catalyst. The m-chloronitrobenzene conversion over the Ni-Co-P catalyst with a suitable Co-content （Co：Ni=1：1, molar ratio） can reach 99.0% and the selectivity of m-chloroaniline can be 99.3%. The composition of the Ni-Co-P catalyst mentioned above was analyzed by X-ray energy dispersive spectrum （EDS）, its amorphous structure was confirmed by X-ray diffraction （XRD） and the transmission electron microscopy （TEM） was used to determine its particle sizes. It is concluded that the main factors affecting the hydrogenation of m-chloronitrobenzene are the unique amorphous structure and the electronic interaction between the Ni and Co, that is, the Co atoms become electron-deficient whereas the Ni atoms become electron-enriched, which could activate the N=O bond and favor to inhibit the hydrodechlorination of chloronitrobenzene.