载体对镍基催化剂催化2,4-二硝基甲苯加氢反应的影响

Effects of Support on the Nickel-Based Catalysts for Hydrogenation of 2,4-Dinitrotoluene

采用浸渍沉淀法制备了Ni/MgO、Ni/HZSM-5、Ni/硅藻土、Ni/SiO2及Ni/HY催化剂,通过XRD、BET、TPR等分析手段对催化剂进行了表征,并将其应用于2,4-二硝基甲苯液相加氢制2,4-甲苯二胺反应。结果表明,在2.2MPa、90℃、反应原料5g、溶剂300mL、催化剂0.5g的条件下,这5种镍基催化剂催化2,4-二硝基甲苯液相加氢反应按2,4-甲苯二胺的选择性高低的排列顺序为Ni/HY、Ni/硅藻土、Ni/SiO2、Ni/HZSM-5、Ni/MgO,其中Ni/HY催化剂催化活性最高,2,4-二硝基甲苯转化率和2,4-甲苯二胺的选择性分别达到99.94%和99.40%,且在循环使用3次后仍能保持良好的催化活性。

A series Ni-based catalysts of Ni/MgO,Ni/HZSM-5,Ni/diatomite,Ni/SiO2 and Ni/HY were prepared by impregnation-precipitation method and characterized by X-ray diffraction（XRD）,nitrogen adsorption-desorption（BET） and temperature-programmed reduction（TPR）,and used to catalyze the process of liquid-phase hydrogenation of 2,4-dinitrotoluene to 2,4-tolylenediamine.Under the reaction conditions of 2.2 MPa,90℃,2,4-dinitrotoluene 5 g,solvent 300 mL,catalyst 0.5 g,the five Ni-based catalysts followed the order of Ni/HY,Ni/diatomite,Ni/SiO2,Ni/HZSM-5,Ni/MgO,according to the order from high to low of 2,4-tolylenediamine selectivity in 2,4-dinitrotoluene catalytic hydrogenation.The Ni/HY catalyst showed the highest catalytic activity with 2,4-dinitrotoluene conversion of 99.94% and 2,4-tolylenediamine selectivity of 99.40%.No obvious deactivation of the catalyst was observed after being reused for three times in the reaction.