Yu Liu, Bolun Yang, Chunhai Yi
May 14, 2013
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Influential Citations
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Journal
Industrial & Engineering Chemistry Research
Abstract
The molecular level understanding of the mechanism about the 3-methylthiophene (3MT) alkylation with isobutylene (IB) as well as the side reaction of IB dimerization over NKC-9 cation exchange resin has been investigated using the density functional theory (DFT) of quantum chemical method. A model of benzene sulfonic acid was used to represent the cation-exchange resin catalyst. Two different reaction mechanism types—stepwise scheme and concerted scheme have been evaluated. Activation energies of each reaction path which were obtained from the DFT results have been improved by single-point MP2 calculations. In the stepwise mechanism, both 3MT alkylation and IB dimerization proceed by adsorption and protonation of the IB to form a sulfonic ester intermediate, and then by C–C bond formation between the sulfonic ester intermediate and another 3MT or IB to give the reaction products. The second step is rate-determining and has activation barriers of 148.41 kJ/mol for 3MT alkylation and 160.52 kJ/mol for IB di...