T. Kabe et al., SULFUR EXCHANGE ON CO-MO AL2O3 HYDRODESULFURIZATION CATALYST USING S-35 RADIOISOTOPE TRACER/, Catalysis today, 29(1-4), 1996, pp. 197-202
A commercial Co-Mo/Al2O3 catalyst was labeled with the radioisotope S-
35 in hydrodesulfurization (HDS) of S-35-labeled dibenzothiophene (S-3
5-DBT) in a high-pressure flow reactor at 50 kg/cm(2). Then, HDS of 4-
methyldibenzothiophene (4-MDBT) and 4,6-dimethyldibenzothiophene (4,6-
DMDBT) or sulfur exchange of H2S were carried out on the labeled catal
yst at 50 kg/cm(2) and 260-360 degrees C. The amounts of labile sulfur
participating in the reaction were determined from the radioactivity
of S-35-H2S released from the S-35-labeled catalyst. In the HDS reacti
ons, the amount of labile sulfur participating in the reaction decreas
ed in the order: DBT > 4-MDBT > 4,6-DMDBT. In the sulfur exchange reac
tion with H2S, the adsorption of H2S on the catalyst reached saturatio
n above a H2S partial pressure of 0.36 kg/cm(2). It was suggested that
the release of H2S from the labile sulfur may be the rate determining
step of the HDS reaction.