Studies of the decomposition of the ethylene hydrophenylation catalyst TpRu(CO)(NCMe)Ph
TpRu(CO)(NCMe)Ph is a catalyst for the conversion of benzene and ethylene to ethylbenzene. Previously, the formation of ethylbenzene has been shown to occur through a pathway that involves ethylene coordination to Ru, insertion of ethylene into the Ru–phenyl bond and Ru–mediated benzene C–H activation. Here, the effect of ethylene pressure and catalyst concentration (between 0.2 and 0.01 mol % based on benzene) on the decomposition of TpRu(CO)(NCMe)Ph was examined. Studies have shown that there are two competing catalyst deactivation pathways. At higher concentrations of TpRu(CO)(NCMe)Ph, the dominant deactivation pathway is likely initiated by a binuclear reaction of two Ru complexes that leads to formation of unidentified paramagnetic species. Kinetic studies show that this pathway for catalyst decomposition occurs with a second-order rate of 0.007 (1) M-1 s-1. At lower Ru concentrations, ethylene C–H activation to form the allyl complex TpRu(CO)(η3-C4H7) is the predominant deactivation pathway. The effect of ethylene pressure on catalyst decomposition was also examined. At higher ethylene pressure nearly quantitative formation of TpRu(CO)(η3-C4H7) was observed.
- Research Organization:
- Univ. of Virginia, Charlottesville, VA (United States); Univ. of North Texas, Denton, TX (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences, and Biosciences Division
- Grant/Contract Number:
- SC0000776; FG02-03ER15387
- OSTI ID:
- 1596960
- Journal Information:
- Journal of Organometallic Chemistry, Vol. 847, Issue C; ISSN 0022-328X
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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