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Title: Adventures on the C3H5O potential energy surface: OH+propyne, OH+allene and related reactions

We mapped out the stationary points and the corresponding conformational space on the C3H5O potential energy surface relevant for the OH + allene and OH + propyne reactions systematically and automatically using the KinBot software at the UCCSD(T)-F12b/cc-pVQZ-F12//M06-2X/6-311++G(d,p) level of theory. We used RRKM-based 1-D master equations to calculate pressure- and temperature-dependent, channel-specific phenomenological rate coefficients for the bimolecular reactions propyne + OH and allene + OH, and for the unimolecular decomposition of the CH3CCHOH, CH3C(OH)CH, CH2CCH2OH, CH2C(OH)CH2 primary adducts, and also for the related acetonyl, propionyl, 2-methylvinoxy, and 3-oxo-1-propyl radicals. The major channel of the bimolecular reactions at high temperatures is the formation propargyl + H2O, which makes the title reactions important players in soot formation at high temperatures. However, below ~1000 K the chemistry is more complex, involving the competition of stabilization, isomerization and dissociation processes. We found that the OH addition to the central carbon of allene has a particularly interesting and complex pressure dependence, caused by the low-lying exit channel to form ketene + CH3 bimolecular products. In this study, we compared our results to a wide range of experimental data and assessed possible uncertainties arising from certain aspects of the theoretical framework.
Authors:
 [1] ;  [2]
  1. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
  2. Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
OSTI Identifier:
1122136
Report Number(s):
SAND--2013-10363J
Journal ID: ISSN 1540-7489; PII: S1540748914001060
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Proceedings of the Combustion Institute
Additional Journal Information:
Journal Volume: 35; Journal Issue: 1; Journal ID: ISSN 1540-7489
Publisher:
Elsevier
Research Org:
Sandia National Laboratories (SNL-CA), Livermore, CA (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY pressure dependence; propargyl; master equation