Equilbrium and kinetic studies of sulfur-coordinated thiophenes (Th) in Cp(CO)[sub 2]Ru([eta][sup 1](S)-Th)[sup +] and Cp(CO)(PPh[sub 3])Ru([eta][sup 1](S)-Th)[sup +]. Models for thiophene adsorption on hydrodesulfurization catalysts

Journal Article · Sun Feb 28 23:00:00 EST 1993 · Organometallics; (United States)

DOI:https://doi.org/10.1021/om00027a018· OSTI ID:5989916

Benson, J W; Angelici, R J ^[1]

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1. Iowa State Univ., Ames (United States)

A series of stable sulfur-bound thiophene complexes, Cp(CO)[sub 2]Ru([eta][sup 1](S)-Th)[sup +], where Cp = [eta][sup 5]-C[sub 5]H[sub 5] and Th = T, 2-MeT, 3-MeT, 2,5-Me[sub 2]T, Me[sub 4]T, BT and DBT, are synthesized from the reaction of Cp(CO)[sub 2]RuCl with Ag[sup +] and thiophenes. Equilibrium constants, K[prime], for the displacement of thiophene (T) by methyl-substituted thiophenes and benzo[b]thiophene (BT), Cp(CO)[sub 2]Ru([eta][sup 1](S)-T)[sup +] + Th [r equilibrium] Cp(CO)[sub 2]Ru([eta][sup 1](S)-Th)[sup +] + T, increase with an increasing number of methyl groups in the thiophene: T(1.00) < 2-MeT (3.30) < 3-MeT (4.76) < 2,5-Me[sub 2]T (20.7) < BT (47.6) < Me[sub 4]T (887). First-order rate constants (10[sup 6]k[sub 1], s[sup [minus]1]) for phosphine substitution of the thiophenes in Cp(CO)[sub 2]Ru([eta][sup 1](S)-Th)[sup +], Cp(CO)[sub 2]Ru([eta][sup 1](S)-Th)[sup +] + PR[sub 3] [yields] Cp(CO)[sub 2]Ru(PR[sub 3])[sup +] + Th, by a dissociative mechanism decrease in the following order: 3-MeT (450) > 2-MeT (410) > BT (100) > 2,5-Me[sub 2]T (23). Rate constants for thiophene dissociation in the analogous Cp(CO)(PPh[sub 3])Ru([eta][sup 1](S)-Th)[sup +] complexes decrease in a slightly different order, T (1400) > 2-MeT (220) > 3-MeT (170) > 2,5-Me[sub 2]T (130) > BT (70) > DBT (17) > Me[sub 4]T (5.8), due to steric repulsions between the bulky PPh[sub 3] and methyl groups in the 2- and 5-positions of the thiophene. In general, methyl groups on the thiophene (Th) increase K[prime] and decrease k[sub 1], which suggests that the electron-releasing methyl groups enhance thiophene binding to the metal. Thiophene binding on a Co-Mo/Al[sub 2]O[sub 3]HDS catalyst also increases with the number of methyl groups in the thiophene. This trend is consistent with [eta][sup 1](S) and/or [eta][sup 5] coordination of thiophenes at metal sites on the catalyst surface. 38 refs., 1 fig., 6 tabs.

• OSTI ID: 5989916
• Journal Information: Organometallics; (United States), Journal Name: Organometallics; (United States) Vol. 12:3; ISSN 0276-7333; ISSN ORGND7
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400 -- Petroleum-- Processing
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical &amp; Physicochemical Properties
ADSORPTION
CATALYSTS
CHEMICAL REACTIONS
COMPLEXES
DATA
DESULFURIZATION
DISSOCIATION
ENERGY SOURCES
FOSSIL FUELS
FUELS
HETEROCYCLIC COMPOUNDS
INFORMATION
KINETICS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANOMETALLIC COMPOUNDS
PETROLEUM
PHOSPHINES
PHOSPHORUS COMPOUNDS
REACTION KINETICS
RUTHENIUM COMPLEXES
SORPTION
SYNTHESIS
THEORETICAL DATA
THIOPHENE
TRANSITION ELEMENT COMPLEXES