Tetramethylbenzenium radical cations as major active intermediates of methanol-to-olefin conversions over phosphorous-modified HZSM-5 zeolites
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SCOPUS
- Title
- Tetramethylbenzenium radical cations as major active intermediates of methanol-to-olefin conversions over phosphorous-modified HZSM-5 zeolites
- Authors
- Jang, HG; Min, HK; Hong, SB; Seo, G
- Date Issued
- 2013-03
- Publisher
- ELSEVIER SCIENCE BV
- Abstract
- The reaction intermediates of methanol-to-olefin (MTO) conversion over phosphorous-modified HZSM-5 (P-MFI) catalysts were investigated by electron spin resonance (ESR) and gas chromatography-mass spectroscopy (GC-MS). Phosphorous modification partially neutralized the strong acid sites in HZSM-5. The phosphorous compounds suppress the migration of polymethylbenzenium radical cations, lowering spin-spin interactions and thus preserved their hyperfine splitting. The ESR spectra of the organic species formed in P-MFI zeolites during MTO conversion were similar to those of the cation species generated from 1,2,4,5-tetramethylbenzene in mordenite. GC-MS of organic extracts revealed the predominant formation of polymethylbenzenes with 4-6 methyl groups. The correlation between conversion and the number of spins of tetramethylbenzenium radical cations exhibited that these radical cations might be major active intermediates of MTO conversion over P-MR catalysts. (C) 2012 Elsevier Inc. All rights reserved.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/14505
- DOI
- 10.1016/j.jcat.2012.12.014
- ISSN
- 0021-9517
- Article Type
- Article
- Citation
- JOURNAL OF CATALYSIS, vol. 299, page. 240 - 248, 2013-03
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