Hydrodesulfurization of sulfur heterocyclic compounds: reaction mechanisms. [Hydrodesulfurization of thianthrene, 1,4,6,9-tetramethylthianthrene, dibenzothiophene, tetraphenylthiophene]

Journal Article · Sun Feb 01 04:00:00 EST 1981 · J. Catal.; (United States)

OSTI ID:6206111

Singhal, G H; Espino, R L; Sobel, J E

The hydrodesulfurization of sulfur heterocyclic compounds over a commercial Co-Mo/..gamma..-Al/sub 2/O/sub 3/ catalyst has been studied under close to commercial conditions (300 to 350/sup 0/C, 20 to 40 atm). The compounds were selected on the basis of stability, steric requirement, and resonance interactions and included thianthrene, 1,4,6,9-tetramethyhianthrene, tetraphenylthiophene, dibenzothiophene, and some of its potential intermediates. The study strongly suggests that the pathways followed by the compounds are structure dependent and can be divided into two categories: (1) in compounds where the electron density is localized on the sulfur atom, desulfurization by direct coordination of the sulfur to a catalyst site can take place giving only the aromatic products; (2) in compounds such as dibenzothiophene in which the electron density of the sulfur atom is delocalized over an extensive ..pi.. system and steric crowding around the sulfur atom is present, the first step in the reaction pathway is probably a ..pi..-complex formation which is followed by hydrogenation and desulfurization. In this case, both aromatic and partially saturated compounds are produced. It is proposed that these products result from a common intermediate suggesting a primarily parallel rather than sequential path for the formation of the hydrogenated products.

• Research Organization: Exxon Research and Engineering Co., Linden, NJ
• OSTI ID: 6206111
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 67:2; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AROMATICS
CATALYST SUPPORTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COBALT
DESULFURIZATION
ELECTRON DENSITY
ELEMENTS
HETEROCYCLIC COMPOUNDS
HIGH TEMPERATURE
HYDROGENATION
KINETICS
MEDIUM PRESSURE
METALS
MOLYBDENUM
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
REACTION INTERMEDIATES
REACTION KINETICS
REFRACTORY METALS
TRANSITION ELEMENTS