Hydrogen atom addition to hydrocarbon guests in radiolyzed zeolites

Journal Article · Thu Oct 28 04:00:00 EDT 1999 · Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical

DOI:https://doi.org/10.1021/jp990740y· OSTI ID:20003232

Werst, D W; Han, P; Choure, S C; Vinokur, E I; Xu, L; Trifunac, A D; Eriksson, L A

The formation of H adducts during radiolysis of zeolites containing olefinic and aromatic hydrocarbon guests was demonstrated to occur by H atom transfer from the zeolite to the adsorbed molecules. The H adducts and other paramagnetic radiolysis products (radical cations and H-loss radicals) were detected by EPR spectroscopy. The mechanism of H adduct formation was confirmed by, inter alia, H/D isotopic labeling and comparison of results in HZSM5 and H-Mordenite to results in their Na{sup +}-exchanged counterparts. The effects of charge transfer among radiolysis products and zeolite-adsorbate interactions on the relative yields of trapped species is discussed. It is proposed that molecules smaller than a critical size adsorb inhomogeneously in ZSM5, forming aggregates in which ion-molecule reactions occur. Interpretation of the experimental results was aided by quantum chemical calculations of the molecular properties of the intermediates and their reaction energetics. This included evaluation of electron-transfer exothermicities, activation energies for H addition, and the relative acidities of the radical cations.

• Research Organization: Argonne National Lab., IL (US)
• Sponsoring Organization: US Department of Energy
• OSTI ID: 20003232
• Journal Information: Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Journal Name: Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical Journal Issue: 43 Vol. 103; ISSN JPCBFK
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
ADDUCTS
ALKENES
AROMATICS
HYDROGEN
RADIOLYSIS
ZEOLITES