Pd/Al2O3表面上活性位性质及其与加氢反应动力学参数间的关系

近年发展起来的新的动态技术能够用于分离测定非均相催化反应的吸附平衡,吸附和表面反应速率系数,而中毒实验使人们能够测定催化剂表面上活性位的容量和强度性质。如果把两者结合起来(可称作动态中毒法)就有可能研究催化剂表面上活性位性质与其动力学参数间的关系。本文的目的,是要在作者早先工作的基础上,在三相浆态床反应器中,应用动态中毒法探索研究Pd/Al_2O_3催化剂表面上活性位性质及其与α-甲基苯乙烯

THE DEPENDENCE OF KINETICS PARAMETERS OF HYDROGENATION REACTION ON THE PROPERTIES OF ACTIVE SITES OF Pd/Al2O3

By dynamic technique, the dependence of adsorption and surface reaction rate coefficients for α-methyl styrene hydrogenation on the properties of active sites of Pd/Al_2O_3 catalyst was studied. The results showed that there were two kinds of active sites on the surface of Pd/Al_O_3. Their number N_t, active frequency AF and the number of active atoms in an active site m were obtained and their variations were also studied. The coefficients of adsorption equilibrium, overall reaction rate and adsorption and surface reaction rate coefficients for a single active site κ~*, κ_0~*, κ_0~* and κ_r were calculated. Their changes with Pd content were as same as that of active frequency AF except for κ_r and the change of κ_r was consistent with that of m value. In summary, the kinetic parameters of a catalytic reaction depend not only on the number of active sites, but also on some properties of the active site, such as AF and m value.