Catalytic cracking of cumene over a silica-alumina catalyst occurred in a laboratory reactor. the observed rate constant during the experiment was 0.90 cm®/(s. gcat) and the order of the reaction was first order. the density and the diameter of the catalyst particle were 1.2 gcat. cm and 0.5 cm, respectively. the effective diffusivity through the catalyst was 1.0 x 10 cm. s! . was there influence of pore diffusion during the experiment?