The Mechanism of Ethylene Dimerization with the Ti(OR %26apos;)(4)/AlR3 Catalytic System: DFT Studies Comparing Metallacycle and Cossee Proposals

作者：Robinson Robert Jr; McGuinness David S^*; Yates Brian F

来源：ACS Catalysis, 2013, 3(12): 3006-3015.

DOI：10.1021/cs4006875

• homogeneous catalysis
• ethylene oligomerization
• ethylene dimerization
• titanium catalysis
• theoretical study

The mechanism of ethylene dimerization to 1-butene, as promoted by the Ti(OR%26apos;)(4)/AlR3 catalyst system, has been explored with the aid of density functional theory (DFT) to determine which mechanistic proposal, metallacycle or Cossee-Arlman, is most likely. The theoretical studies predict that the Cossee mechanism has the lowest rate-determining reaction barrier and also that this mechanism is more likely to lead to selective dimerization. In contrast, for the metallacycle mechanism, a higher likelihood of 1-hexene formation is predicted. The possibility of isomerization or codimerization of 1-butene has also been studied according to a Cossee mechanism, with the results obtained in good agreement with previous experiments. As a result of this study and recent experimental results, a Cossee mechanism of dimerization with this catalyst, proceeding via a titanium-hydride intermediate, is considered the most probable route.

• 出版日期2013-12