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Title: Reaction mechanism of dimethyl ether carbonylation to methyl acetate over mordenite – a combined DFT/experimental study

The reaction mechanism of dimethyl ether carbonylation to methyl acetate over mordenite was studied theoretically with periodic density functional theory calculations including dispersion forces and experimentally in a fixed bed flow reactor at pressures between 10 and 100 bar, dimethyl ether concentrations in CO between 0.2 and 2.0%, and at a temperature of 438 K. The theoretical study showed that the reaction of CO with surface methyl groups, the rate-limiting step, is faster in the eight-membered side pockets than in the twelve-membered main channel of the zeolite; the subsequent reaction of dimethyl ether with surface acetyl to form methyl acetate was demonstrated to occur with low energy barriers in both the side pockets and in the main channel. Here, the present analysis has thus identified a path, where the entire reaction occurs favourably on a single site within the side pocket, in good agreement with previous experimental studies. The experimental study of the reaction kinetics was consistent with the theoretically derived mechanism and in addition revealed that the methyl acetate product inhibits the reaction – possibly by sterically hindering the attack of CO on the methyl groups in the side pockets.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [2] ;  [4] ;  [5] ; ORCiD logo [1]
  1. Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Chemical and Biochemical Engineering
  2. Haldor Topsoe A/S, Lyngby (Denmark)
  3. SLAC National Accelerator Lab., Menlo Park, CA (United States). SUNCAT Center for Interface Science and Catalysis
  4. Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Physics
  5. Technical Univ. of Denmark, Lyngby (Denmark). Centre for Catalysis and Sustainable Chemistry, Dept. of Chemistry
Publication Date:
Grant/Contract Number:
AC02-76SF00515
Type:
Accepted Manuscript
Journal Name:
Catalysis Science and Technology
Additional Journal Information:
Journal Volume: 7; Journal Issue: 5; Journal ID: ISSN 2044-4753
Publisher:
Royal Society of Chemistry
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1353213

Rasmussen, D. B., Christensen, J. M., Temel, B., Studt, F., Moses, P. G., Rossmeisl, J., Riisager, A., and Jensen, A. D.. Reaction mechanism of dimethyl ether carbonylation to methyl acetate over mordenite – a combined DFT/experimental study. United States: N. p., Web. doi:10.1039/c6cy01904h.
Rasmussen, D. B., Christensen, J. M., Temel, B., Studt, F., Moses, P. G., Rossmeisl, J., Riisager, A., & Jensen, A. D.. Reaction mechanism of dimethyl ether carbonylation to methyl acetate over mordenite – a combined DFT/experimental study. United States. doi:10.1039/c6cy01904h.
Rasmussen, D. B., Christensen, J. M., Temel, B., Studt, F., Moses, P. G., Rossmeisl, J., Riisager, A., and Jensen, A. D.. 2017. "Reaction mechanism of dimethyl ether carbonylation to methyl acetate over mordenite – a combined DFT/experimental study". United States. doi:10.1039/c6cy01904h. https://www.osti.gov/servlets/purl/1353213.
@article{osti_1353213,
title = {Reaction mechanism of dimethyl ether carbonylation to methyl acetate over mordenite – a combined DFT/experimental study},
author = {Rasmussen, D. B. and Christensen, J. M. and Temel, B. and Studt, F. and Moses, P. G. and Rossmeisl, J. and Riisager, A. and Jensen, A. D.},
abstractNote = {The reaction mechanism of dimethyl ether carbonylation to methyl acetate over mordenite was studied theoretically with periodic density functional theory calculations including dispersion forces and experimentally in a fixed bed flow reactor at pressures between 10 and 100 bar, dimethyl ether concentrations in CO between 0.2 and 2.0%, and at a temperature of 438 K. The theoretical study showed that the reaction of CO with surface methyl groups, the rate-limiting step, is faster in the eight-membered side pockets than in the twelve-membered main channel of the zeolite; the subsequent reaction of dimethyl ether with surface acetyl to form methyl acetate was demonstrated to occur with low energy barriers in both the side pockets and in the main channel. Here, the present analysis has thus identified a path, where the entire reaction occurs favourably on a single site within the side pocket, in good agreement with previous experimental studies. The experimental study of the reaction kinetics was consistent with the theoretically derived mechanism and in addition revealed that the methyl acetate product inhibits the reaction – possibly by sterically hindering the attack of CO on the methyl groups in the side pockets.},
doi = {10.1039/c6cy01904h},
journal = {Catalysis Science and Technology},
number = 5,
volume = 7,
place = {United States},
year = {2017},
month = {1}
}

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