Mechanisms of thiophene hydrodesulfurization on model molybdenum catalysts
- Univ. of Texas, Austin, TX (United States). Dept. of Chemical Engineering
Hydrodesulfurization (HDS) activities and selectivities were measured for thiophene, tetrahydrothiophene (THT), and 1-butanethiol on silica-supported molybdenum catalysts at a pressure of 1 atm and temperatures ranging from 530 to 795 K. The model catalysts, which were previously characterized, feature isolated molybdenum atoms in the +2, +4, and +6 oxidation states and molybdenum dimers with each molybdenum atom in the +4 oxidation state. Silica-supported MoS{sub 2} was used for reference. Activities for thiophene and THT HDS correlate with oxidation state. Mo(II) is most active among dispersed catalysts. 1-Butanethiol activities were much larger than thiophene or THT activities and were roughly equal on all dispersed catalysts. Apparent activation energies of 43.4 and 48.5 kJ/mol were determined for thiophene HDS on Mo(II) and MoS{sub 2}/SiO{sub 2}, respectively. Dihydrothiophene, THT and 1-butanethiol were formed in thiophene HDS over Mo(II) and MoS{sub 2}/SiO{sub 2}. The major products of thiophene and THT HDS were 1-butene, 2-butene, and n-butene. Butadiene, i-butane, i-butene, methane, ethane, ethene, propane, and propene were formed in small amounts. Butadiene is thought to be the initial product of thiophene and THT desulfurization and undergoes subsequent hydrogenation and isomerization to yield the observed products. A common mechanism for HDS of thiophene and THT with 2,5-DHT as an intermediate is discussed.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG03-95ER14570
- OSTI ID:
- 659080
- Journal Information:
- Journal of Catalysis, Vol. 178, Issue 1; Other Information: PBD: 15 Aug 1998
- Country of Publication:
- United States
- Language:
- English
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