All the data reported previously have been reevaluated to determine the quantitative reaction network for dibenzothiophene hydrodesulfurization at about 100 atm and 300/sup 0/C. This network shows the high selectivity of the catalyst for simple hydrodesulfurization (biphenyl + H/sub 2/S formation). When methyl groups are present in the 4 and 6 positions of dibenzothiophene, the primary hydrogenation reaction is approximately as fast as the primary hydrodesulfurization reaction. Ni and Mo or Ni and W used instead of Co and Mo in the catalyst, or H/sub 2/S in the reactant mixture, also favor hydrogenation relative to hydrodesulfurization. Previous results have been …
continued below
Publisher Info:
Delaware Univ., Newark (USA). Dept. of Chemistry
Place of Publication:
Newark, Delaware
Provided By
UNT Libraries Government Documents Department
Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.
All the data reported previously have been reevaluated to determine the quantitative reaction network for dibenzothiophene hydrodesulfurization at about 100 atm and 300/sup 0/C. This network shows the high selectivity of the catalyst for simple hydrodesulfurization (biphenyl + H/sub 2/S formation). When methyl groups are present in the 4 and 6 positions of dibenzothiophene, the primary hydrogenation reaction is approximately as fast as the primary hydrodesulfurization reaction. Ni and Mo or Ni and W used instead of Co and Mo in the catalyst, or H/sub 2/S in the reactant mixture, also favor hydrogenation relative to hydrodesulfurization. Previous results have been evaluated in light of the recent literature to provide a new interpretation of the reaction mechanism of catalytic hydrodesulfurization on surfaces of sulfided Co-Mo/Al/sub 2/0/sub 3/. It has often been assumed that catalytic hydrodesulfurization of thiophene and related compounds proceeds via a one-point end-on adsorption involving bonding of the sulfur atom with Mo ions at an anion vacancy on the catalyst surface. This interpretation is inadequate, failing to account for deuterium-exchange results, the reactivities of benzothiophene and dibenzothiophene, and the small steric effects of methyl substituents affecting the adsorption and reaction of compounds in the thiophene, benzothiophene, and dibenzothiophene families of homologs. An alternative mechanism, presented, here, involves a multipoint adsorption of the reactant, with a C=C bond interacting with the Mo cation and the S atom of the reactant interacting with a S ion on the surface. The new mechanism accounts for the observed deuterium exchange and hydrodesulfurization reactions and is consistent with the observed steric effects.
This report is part of the following collection of related materials.
Office of Scientific & Technical Information Technical Reports
Reports, articles and other documents harvested from the Office of Scientific and Technical Information.
Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.
Gates, Bruce C.; Katzer, James R.; Olson, Jon H.; Kwart, Harold & Stiles, Alvin B.Kinetics and mechanism of desulfurization and denitrogenation of coal-derived liquids. Twelfth quarterly report, March 21-June 20, 1978,
report,
October 20, 1978;
Newark, Delaware.
(https://digital.library.unt.edu/ark:/67531/metadc1085229/:
accessed January 19, 2025),
University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu;
crediting UNT Libraries Government Documents Department.