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Title: An experimental and theoretical study of the thermal decomposition of C 4H 6 isomers

The chemistry of small unsaturated hydrocarbons, such as 1,3–butadiene (1,3–C 4H 6), 1,2–butadiene (1,2–C 4H 6), 2–butyne (2–C 4H 6) and 1–butyne (1–C 4H 6), is of central importance to the modeling of combustion systems. These species are important intermediates in combustion processes, and yet their high-temperature chemistry remains poorly understood, with various dissociation and isomerization pathways proposed in the literature. Here we investigate the thermal decompositions of 1,3–C 4H 6, 1,2–C 4H 6, 2–C 4H 6 and 1–C 4H 6 inside a diaphragmless shock tube, at post shock total pressures of 26–261 Torr and temperatures ranging from 1428–2354 K, using laser schlieren densitometry. The experimental work has been complemented by high-level ab initio calculations, which collectively provide strong evidence that formally direct dissociation is the major channel for pyrolysis of 1,3–C 4H 6 and 2–C 4H 6; these paths have not been previously reported but are critical to reconciling the current work and disparate literature reports. The reaction mechanism presented here simulates the current experiments and experimental data from the literature very well. As a result, pressure and temperature dependent rate coefficients are given for the isomerization, formally direct and direct dissociation paths.
Authors:
 [1] ; ORCiD logo [2] ;  [1] ; ORCiD logo [3] ; ORCiD logo [1]
  1. Argonne National Lab. (ANL), Argonne, IL (United States)
  2. Brown Univ., Providence, RI (United States)
  3. Argonne National Lab. (ANL), Argonne, IL (United States); The Univ. of Chicago, Chicago, IL (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory
Additional Journal Information:
Journal Volume: 121; Journal Issue: 20; Journal ID: ISSN 1089-5639
Publisher:
American Chemical Society
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1371560