The effects of titanocene dichloride on dibenzothiophene hydrodesulfurization and dibenzofuran hydrodeoxygenation over three different kinds of catalysts were studied by using a Berty type gradientless reactor. The reaction rates and the rate constants were calculated by assuming a pseudo-first order reaction model. By comparing the reactant conversion and the rate constants, titanocene dichloride did not appear to have any effect on dibenzothiophene hydrodesulfurization either over NiMo/alumina or over CoMo/alumina but it increased the catalyst activity in the case of dibenzofuran hydrodeoxygenation over both NiMo/alumina and CoMo/alumina catalyst. No conversion was observed in all of the experimental runs which were done over plain alumina. The coke content of NiMo/alumina catalyst in the hydrodeoxygenation run was found to be lower while that of CoMo/alumina catalyst in both hydrodeoxygenation and hydrodesulfurization runs appeared to be higher with the addition of titanocene dichloride.Chemical Engineerin