对硝基苯胺催化加氢合成对苯二胺的绿色工艺

建立了一种以对硝基苯胺和氢气为原料、水为溶剂、Raney Ni为催化剂,进行催化加氢反应合成对苯二胺的绿色工艺。研究了以水为溶剂的可行性,考察了反应压力、反应温度、搅拌转速、对硝基苯胺用量、催化剂用量等反应条件对加氢反应的影响,以及溶剂和催化剂的重复使用性能。实验结果表明,对硝基苯胺催化加氢合成对苯二胺的适宜反应条件为:水用量400 mL、对硝基苯胺用量175 g、Raney Ni催化剂用量5.0 g、搅拌转速1 000 r/min、反应温度50℃、反应压力3.0 MPa;在此条件下,对硝基苯胺的转化率为100.0%,对苯二胺的收率为98.9%,对苯二胺的纯度为100.0%(w);反应过程中溶剂和催化剂可重复使用。整个工艺过程安全环保,成本低,能耗低,收益高。

Green Process for Synthesis of p-Phenylenediamine by Catalytic Hydrogenation of p-Nitroaniline

The synthesis of p-phenylenediamine by the hydrogenation of p-nitroaniline on a Rainey nickel catalyst with water as the solvent was studied,which was a green process.The influences of reaction conditions,namely reaction pressure,reaction temperature,stirring speed,p-nitroaniline dosage and catalyst dosage on the catalytic hydrogenation were investigated.The results showed that under the optimum reaction conditions:water dosage 400 mL,p-nitroaniline dosage 175 g,Raney Ni catalyst dosage 5.0 g,stirring speed 1 000 r/min,reaction temperature 50 ℃ and reaction pressure 3.0 MPa,the conversion of p-nitroaniline,the yield and purity of p-nitroaniline could reach 100.0%,98.9% and 100.0%(w),respectively.Both the solvent and the catalyst could be reused.The process is safe and environmentally friendly with low cost and low energy consumption.