Organometallic and reactor studies of the thiophene hydrodesulfurization mechanism
A series of compounds are prepared to study the effects of methyl groups on the chemical reaction kinetics of thiophene hydrodesulfurization. The 2-benzothienyl complexes, Cp(PMe[sub 3])[sub 2]Ru(2-BTyl) (1) and Cp(CO) (PPh[sub 3])Ru(2-BTyl) (2) are prepared from reactions of 2-benzothienyllithium with Cp(PMe[sub 3])[sub 2]RuX (X = Cl, CF[sub 3]SO[sub 3]) and [eta][sup 1] (S)-benzo[b]thiophene (BT) complex Cp(CO) (PPh[sub 3])Ru ([eta][sup 1] (S)-BT)[sup +] (4). The analogous protonation of 1 appears to initially add H[sup +] to the S atom in the BTyl ligand; this intermediate subsequently rearranges to the [eta][sup 1](S)-BT[sup +] (3). These reactions suggest a possible pathway for deuterium exchange in the 2-position of benzothiophene over hydrodesulfurization catalysts. The deuterodesulfurization (DDS) of thiophene was investigated over PbMo[sub 6.2]S[sub 8] at 400[degrees]C using a flow-microreactor. The product 1,3- butadiene (BDE), which is likely to be the first desulfurized product under these conditions, was analyzed for deuterium content by [sup 2]H NMR and mass spectrometries. At different levels of thiophene conversion (0.86-10.2%), the amount of deuterium incorporated into BDE remains constant. Unconverted thiophene incorporates 0.42 D atoms at 10.2% thiophene conversion but only 0.05 D atoms at 0.86% conversion. Reaction of 2,5-dihydrothiophene (2,5-DHT) with D[sub 2] at 200[degrees]C over PbMo[sub 6.2]S[sub 8] liberates BDE as the only hydrocarbon product. The BDE, however, incorporates no deuterium. Thiophene, H[sub 2]S and 2,5-DHT effectively poison the catalyst, inhibiting both BDE hydrogenation and deuterium exchange. Results of this study are used to indicate which thiophene HDS mechanisms most likely occur under these conditions over PbMo[sub 6.2]S[sub 8].
- Research Organization:
- Iowa State Univ. of Science and Technology, Ames, IA (United States)
- OSTI ID:
- 6974062
- Country of Publication:
- United States
- Language:
- English
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Organometallic and reactor studies of the thiophene hydrodesulfurization mechanism
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Related Subjects
400201* -- Chemical & Physicochemical Properties
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DESULFURIZATION
HETEROCYCLIC COMPOUNDS
KINETICS
LEAD COMPOUNDS
LEAD SULFIDES
MOLYBDENUM COMPOUNDS
MOLYBDENUM SULFIDES
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANOMETALLIC COMPOUNDS
REACTION KINETICS
REFRACTORY METAL COMPOUNDS
SULFIDES
SULFUR COMPOUNDS
THIOPHENE
TRANSITION ELEMENT COMPOUNDS