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Title: Formation and emission of large furans and oxygenated hydrocarbons from flames

Many oxygenated hydrocarbon species formed during combustion, such as furans, are highly toxic and detrimental to human health and the environment. These species may also increase the hygroscopicity of soot and strongly influence the effects of soot on regional and global climate. However, large furans and associated oxygenated species have not previously been observed in flames, and their formation mechanism and interplay with polycyclic aromatic hydrocarbons (PAHs) are poorly understood. We report on a synergistic computational and experimental effort that elucidates the formation of oxygen-embedded compounds, such as furans and other oxygenated hydrocarbons, during the combustion of hydrocarbon fuels. We used ab initio and probabilistic computational techniques to identify low-barrier reaction mechanisms for the formation of large furans and other oxygenated hydrocarbons. We used vacuum-UV photoionization aerosol mass spectrometry and X-ray photoelectron spectroscopy to confirm these predictions. We show that fura ns are produced in the high- Temperature regions of hydrocarbon flames, where they remarkably survive and become the main functional group of oxygenates that incorporate into incipient soot. In controlled flame studies, we discovered ~100 oxygenated species previously unaccounted for. We found that large alcohols and enols act as precursors to furans, leading to incorporation of oxygen into themore » carbon skeletons of PAHs. Our results depart dramatically from the crude chemistry of carbonand oxygen-containing molecules previously considered in hydrocarbon formation and oxidation models and spearhead the emerging understanding of the oxidation chemistry that is critical, for example, to control emissions of toxic and carcinogenic combustion by-products, which also greatly affect global warming.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [1] ;  [5] ;  [6] ;  [6] ;  [7] ;  [1]
  1. Sandia National Lab. (SNL-CA), Livermore, CA (United States). Combustion Research Facility
  2. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Mechanical Engineering
  3. Stanford Univ., CA (United States). Dept. of Materials Science & Engineering
  4. Sandia National Lab. (SNL-CA), Livermore, CA (United States). Materials Physics Dept.
  5. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Sciences Division; Univ. of California, Berkeley, CA (United States). Dept. of Chemistry
  6. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Sciences Division
  7. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Mechanical Engineering; Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Chemical Engineering; Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Macromolecular Science and Engineering and Biophysics Program
Publication Date:
Grant/Contract Number:
AC02-05CH11231; AC04-94AL85000; SC0002619
Type:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 113; Journal Issue: 30; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; furans; oxygenated hydrocarbons; soot; organic carbon; black carbon
OSTI Identifier:
1260993
Alternate Identifier(s):
OSTI ID: 1379529