钯/陶瓷膜催化剂上对硝基苯酚加氢宏观动力学

对硝基苯酚催化加氢法是制备对氨基苯酚的一种清洁合成工艺。采用液相浸渍还原法将钯催化剂负载于陶瓷膜表面制备钯/陶瓷膜催化剂,对该膜催化剂上对硝基苯酚加氢的宏观动力学进行了研究。在高压反应釜中考察了对硝基苯酚浓度、氢气压力以及反应温度等因素对对硝基苯酚加氢速率的影响,并采用幂函数方程进行实验数据拟合。实验结果表明,反应对对硝基苯酚呈0级,对氢气是1.05级,反应活化能为17.88 kJ/mol,指前因子为2 304 mol/(h·m2·MPa1.05)。依据上述结果建立了反应的宏观动力学方程,并对模型进行验证,结果表明模型计算值与实验结果吻合较好。这可为钯/陶瓷膜催化对硝基苯酚加氢制备对氨基苯酚的过程开发提供基础数据。

Macro-kinetics of p-nitrophenol hydrogenation on Pd/ceramic membrane catalysts

The catalytic hydrogenation of p-nitrophenol is a green route for the preparation of p-aminophenol.The Pd/ceramic membrane catalysts were prepared by the liquid impregnation-reduction method with Pd catalysts immobilized on the surface of ceramic membrane,and the macro-kinetics of p-nitrophenol hydrogenation on the catalysts was studied.The effects of p-nitrophenol concentration,hydrogen pressure and reaction temperature on the hydrogenation rate of p-nitrophenol were investigated in an autoclave.The data were fitted by the power function equation.The results show that the reaction order is 0 for p-nitrophenol and 1.05 for hydrogen,respectively.The reaction activation energy is 17.88 kJ/mol and the pre-exponential factor is 2 304 mol/(h·m2·MPa1.05).On that basis,the macro kinetics model of p-nitrophenol hydrogenation on the Pd/ceramic membrane catalyst was established and verified.The calculated values are in good agreement with the experimental results.The study provides the fundamental data for the p-aminophenol process development by the catalytic hydrogenation of p-nitrophenol on Pd/ceramic membrane catalysts.