skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Time-resolved study of actyl radical in zeolite NaY by step-scan FT-IR spectroscopy

Abstract

Step-scan FT-infrared spectroscopy of 1-naphthyl acetate and pinacolone photodissociation in zeolite NaY revealed a transient at 2125 cm{sup {minus}1} assigned to acetyl radical. Comparison of the intensities of transient and final product absorptions, 2-acetyl-1-naphthol in the case of naphthyl acetate and acetaldehyde for pinacolone, indicates that the acetyl radical represents the main, and probably only, reaction channel. The decay of the radical at room temperature is best described by a single-exponential law with a lifetime of 71 {+-} 15 {micro}s (1-naphthyl acetate) and 315 {+-} 30 {micro}s (pinacolone). This constitutes the first detection and kinetic study of a small transient radical in a zeolite. The kinetic result is interpreted in terms of complete separation of the photogenerated pairs from the parent supercage, followed by random walks in subspaces of the zeolite lattice imposed by the much less mobile precursor molecules. These force the geminate radicals to react and thereby contribute to the high selectivity of these photoreactions.

Authors:
;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab., CA (US); Univ. of California, Berkeley, CA (US)
Sponsoring Org.:
USDOE
OSTI Identifier:
20075902
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory
Additional Journal Information:
Journal Volume: 104; Journal Issue: 18; Other Information: PBD: 11 May 2000; Journal ID: ISSN 1089-5639
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ACETYL RADICALS; ZEOLITES; DISSOCIATION; FOURIER TRANSFORM SPECTROMETERS; CHEMICAL REACTION KINETICS

Citation Formats

Vasenkov, S., and Frei, H. Time-resolved study of actyl radical in zeolite NaY by step-scan FT-IR spectroscopy. United States: N. p., 2000. Web. doi:10.1021/jp994366d.
Vasenkov, S., & Frei, H. Time-resolved study of actyl radical in zeolite NaY by step-scan FT-IR spectroscopy. United States. doi:10.1021/jp994366d.
Vasenkov, S., and Frei, H. Thu . "Time-resolved study of actyl radical in zeolite NaY by step-scan FT-IR spectroscopy". United States. doi:10.1021/jp994366d.
@article{osti_20075902,
title = {Time-resolved study of actyl radical in zeolite NaY by step-scan FT-IR spectroscopy},
author = {Vasenkov, S. and Frei, H.},
abstractNote = {Step-scan FT-infrared spectroscopy of 1-naphthyl acetate and pinacolone photodissociation in zeolite NaY revealed a transient at 2125 cm{sup {minus}1} assigned to acetyl radical. Comparison of the intensities of transient and final product absorptions, 2-acetyl-1-naphthol in the case of naphthyl acetate and acetaldehyde for pinacolone, indicates that the acetyl radical represents the main, and probably only, reaction channel. The decay of the radical at room temperature is best described by a single-exponential law with a lifetime of 71 {+-} 15 {micro}s (1-naphthyl acetate) and 315 {+-} 30 {micro}s (pinacolone). This constitutes the first detection and kinetic study of a small transient radical in a zeolite. The kinetic result is interpreted in terms of complete separation of the photogenerated pairs from the parent supercage, followed by random walks in subspaces of the zeolite lattice imposed by the much less mobile precursor molecules. These force the geminate radicals to react and thereby contribute to the high selectivity of these photoreactions.},
doi = {10.1021/jp994366d},
journal = {Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory},
issn = {1089-5639},
number = 18,
volume = 104,
place = {United States},
year = {2000},
month = {5}
}