对硝基苯胺水相加氢合成对苯二胺

Synthesis of p-Phenylenediamine by Hydrogenation of p-Nitroaniline in Water

摘要:

以对硝基苯胺为原料，水为溶剂，考察了水相中负载型镍催化剂催化对硝基苯胺加氢还原的反应性能，并开展了中试实验。考察了反应温度、压力、保温时间、对硝基苯胺浓度、废水套用等因素对催化加氢反应性能的影响。实验结果表明，产品对苯二胺质量分数较高，催化剂和水可循环使用。较佳的工艺条件为：温度110 ℃，保温时间2~3 h，压力2.0 MPa，搅拌转速800 r/min，起始催化剂用量10%（以对硝基苯胺的质量为基准，下同），催化剂损耗0.2%（以起始添加剂催化剂的质量为基准）。此工艺条件下，对硝基苯胺转化率100%，对苯二胺产率99.5%以上。废水套用后排放废水量很少，且对催化剂催化活性、产品质量等没有影响。

Abstract:

The reactive behavior on hydrogenation of p-nitroaniline in water catalyzed by supported nickel catalyst was studied. The laboratory test and pilot-plant test were conducted. The effects of reaction temperature, pressure, holding time, p-nitroaniline mass concentration and wastewater recycle on the hydrogenation reaction were investigated. The results showed that the product p-phenylenediamine has high mass fraction, and catalyst and water can be recycled. The optimal reaction parameters are that temperature 110℃, reaction time 2~3 h, pressure 2.0 MPa, stirring speed 800 r/min, dosage of initial catalyst 10% (based on the mass of p-nitroaniline, similarly hereinafter), catalyst loss 0.2% (based on the additive mass of initial catalyst). Under these optimal reaction conditions, the conversion of p-nitroaniline was 100%, and the yield of p-phenylenediamine was over 99.5%. The amount of wastewater discharged after wastewater recycle was small and had no effect on catalytic activity and product quality.