滴流床反应器中镍基催化剂催化加氢合成间苯二胺工艺的研究

以Ni／La2O3-SiO2为催化剂，采用滴流床反应器较系统地考察了反应温度、压力、气体和液体空速、溶剂等因素对问二硝基苯液相催化加氢合成间苯二胺反应的影响规律。结果表明，在较佳的温度范围内催化剂具有较好的间二硝基苯转化率及间苯二胺选择性，温度过低间苯二胺选择性较低，而温度过高会使间二硝基苯的转化率下降。反应压力及氢气空速提高、间二硝基苯液时空速降低均有刺于提高间二硝基苯的转化率和间苯二胺的选择性。乙酸乙酯对间二硝基苯有良好溶解性能，以乙酸乙酯作为溶剂可以提高催化剂的反应性能。在实验确定的适宜加氢反应工艺条件下，间二硝基苯转化率和间苯二胺选择性均可以达到99．5％以上。

Synthesis Technology of m-Phenylenediamine by Catalytic Hydrogenation over Nickel-Based Catalyst in Trickle-Bed Reactor

The catalytic hydrogenation of m-dinitrobenzene (MDNB) to m-phenylenediamine (MPD) was tested over Ni/La2O3-SiO2 catalyst in a trickle-bed reactor. Effects of the reaction conditions,such as temperature, pressure, space velocity of hydrogen and MDNB and kinds of solvents on the reactivity of the catalyst were systematically investigated. It was found that there existed higher MDNB conversion and MPD selectivity in a proper temperature range. Lower temperature was unfavorable to MPD selectivity, and MPDB conversion decreased at higher temperature. With the increase of pressure and GHSV of H2, the conversion of MDNB and the selectivity of MPD both enhanced. There existed higher catalytic performance of the catalyst with ethylacetate as the solvent due to a better dissolution of MDNB in ethylacetate than in ethanol. With ethylacetate as solvent, the conversion of MDNB and the selectivity of MPD both exceeded 99. 5% under the optimal reaction conditions confirmed by the experiment.