Redox机理动力学内扩散影响的特征

在Pb_0.88Bi_0.06La_0.02Mo/SiO₂催化剂上,反应在动力学区域进行时,甲醇氧化制甲醛服从Redox机理动力学方程:r=(k₁k₂P甲醇Po₂)/(0.5k₁P甲醇+k₂Po₂)当催化剂颗粒增大至3mm时,内扩散影响严重,催化剂有效因子在0.38-0.73之间,其内扩散区域的速度方程为r内=(Do₂/RTKL)2φ_MK(Po₂-Po_2.o)-ln(1+Kpo₂/1+Kpo_2.o)]^1/2测定了反应受O₂内扩散控制时的反应活化能E内为74.5kJ/mol。

The Characteristics of Effect of Intraparticle Diffusion on the Kinetics of Redox Mechanism

The kinetics of oxidation of methanol to formaldehyde over Pb_0.88Bi_0.06La_0.02Mo/SiO₂catalyst was described by Redox mechanism of two stages.When the particles of catalyst increased to 3 mm in diameter, the effect of intraparticle diffusion strongly depended on the rate of oxidation of methanol to formaldehyde. The effectiveness factor of catalyst was determined by experiments to be 0.38-0.73.The kinetic equation of Redox mechanism in the presence of intraparticle diffusion of oxygen was interpretated by the theory of intraparticle diffusion and proved by experiments.The apparent activation energies of oxidation of methanol in the presence of intraparticle diffusion of oxygen were determined and interpreted by the kinetic experiments and a theoritical equation.