Reaction mechanism of phenol alkylation with tert-butyl alcohol over Hb zeolite: An ONIOM study

Xiaowa Nie, Xin Liu, Chunshan Song, Min Liu, Xinwen Guo

Research output: Contribution to journalConference article

Abstract

Alkylation of phenol with tert-butyl alcohol (TBA) over Hb zeolite was studied using ONIOM approach with two proposed reaction paths: stepwise and concerted mechanisms. The computational results obtained by the ONIOM (B3LYP/6-31G(d,p):UFF) method revealed that the reaction preferentially occurs through a concerted mechanism rather than via the stepwise mechanism. The reactivity difference between the 2- and 4-tert-butylation became more apparent in the concerted mechanism where the 2-tert-butylation proceeded faster. The reaction activation energies of the 2- and 4-tert-butylation were predicted to be 110.7 and 121.9kJ/mol, respectively. In the stepwise mechanism, the formation of the tert-butyl carbenium species was the rate-limiting step. In the subsequent tert-butylation process, phenol tert-butylation was faster than the tert-butyl carbenium formation, with the activation energies of 94.3 and 99.3 kJ/mol for the 2- and 4-tert-butylation, respectively. It was found that 2-tert-butyl phenol was a kinetically favored product, whereas 4-tert-butyl phenol was the thermodynamically most preferred product.

Original languageEnglish (US)
JournalACS National Meeting Book of Abstracts
StatePublished - Dec 1 2010
Event239th ACS National Meeting and Exposition - San Francisco, CA, United States
Duration: Mar 21 2010Mar 25 2010

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All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)

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