학술논문

193-nm photodissociation of acryloyl chloride to probe the unimolecular dissociation of CH[sub 2]CHCO radicals and CH[sub 2]CCO.
Document Type
Article
Source
Journal of Chemical Physics. 3/1/2004, Vol. 120 Issue 9, p4223-4230. 8p. 1 Diagram, 1 Chart, 13 Graphs.
Subject
*CHLORIDES
*PHOTODISSOCIATION
*NUCLEAR energy
*SPECTRUM analysis
*HYDROCHLORIC acid
*STOPPING power (Nuclear physics)
Language
ISSN
0021-9606
Abstract
The work presented here uses photofragment translational spectroscopy to investigate the primary and secondary dissociation channels of acryloyl chloride (CH[sub 2]==CHCOCl) excited at 193 nm. Three primary channels were observed. Two C–Cl fission channels occur, one producing fragments with high kinetic recoil energies and the other producing fragments with low translational energies. These channels produced nascent CH[sub 2]CHCO radicals with internal energies ranging from 23 to 66 kcal/mol for the high-translational-energy channel and from 50 to 68 kcal/mol for the low-translational-energy channel. We found that all nascent CH[sub 2]CHCO radicals were unstable to CH[sub 2]CH+CO formation, in agreement with the G3//B3LYP barrier height of 22.4 kcal/mol to within experimental and computational uncertainties. The third primary channel is HCl elimination. All of the nascent CH[sub 2]CCO coproducts were found to have enough internal energy to dissociate, producing CH[sub 2]C:+CO, in qualitative agreement with the G3//B3LYP barrier of 39.5 kcal/mol. We derive from the experimental results an upper limit of 23±3 kcal/mol for the zero-point-corrected barrier to the unimolecular dissociation of the CH[sub 2]CHCO radical to form CH[sub 2]CH+CO. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]