在 Pt/Al_2O_3催化剂上气相苯加氢反应的动力学

KINETICS OF BENZENE HYDROGENATION REACTION IN GAS PHASE ON Pt/Al_2O_3

在研制得到了高活性和高选择性 Pt/Al_2O_3催化剂的基础上,采用微反-色谱联用装置考察了气相苯加氢反应的动力学。假定在催化剂表面上存在着两种不同的活性中心,一种吸附氧;另一种吸附苯、环己烷及反应中间物,并假定吸附氢与吸附苯间的表面反应为过程的控制步骤,从而导出动力学方程。通过实验测得了不同反应条件下的反应速率和组分分压,并用非线性回归方法处理实验数据,求得方程中各参数。通过偏差分析、方差分析及 Boudart 提出的四条判断准则,验证了动力学模型及回归参数的合理性。结果得到了此动力学模型与实验数据较好地吻合。在此基础上测定了反应的活化能及氢、苯和环已烷的吸附热。

The kinetics of benzene hydrogenation reaction in gas phase on Pt/Al_2O_3 was investigated by using micro-reactor-chromatograph.The catalysts(Pt/Al_2O_3)which possess high activity and selectivity were prepared in our laboratory.We assume that two different active centers exist on the surface of the catalyst,one of them can adsorb hydrogen,the other can adsorb benzene, cyclohexane and the intermediates.The kinetic equation was derived by supposing that the surface reaction between adsorbed hydrogen and adsorbed benzene is the control step of the rate.The reaction rates and the partial pressures of the components at different reaction conditions were measured by experiment.The experimental data were treated by non-linear regression and the parameters in the equations were obtained.The reasonability of the kinetic model and the regression parameters were verified by deviation analysis and Boudart-criteria.The result was that the kinetic model tallies relative good with the experimental data.On the basis of the above results,the reaction activiation energy and the adsorption heats of hydrogen,benzene and cyelohexane were obtained.