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Title: Unraveling the structure and chemical mechanisms of highly oxygenated intermediates in oxidation of organic compounds

Decades of research on the autooxidation of organic compounds have provided fundamental and practical insights into these processes; however, the structure of many key autooxidation intermediates and the reactions leading to their formation still remain unclear. This work provides additional experimental evidence that highly oxygenated intermediates with one or more hydroperoxy groups are prevalent in the autooxidation of various oxygenated (e.g., alcohol, aldehyde, keto compounds, ether, and ester) and nonoxygenated (e.g., normal alkane, branched alkane, and cycloalkane) organic compounds. These findings improve our understanding of autooxidation reaction mechanisms that are routinely used to predict fuel ignition and oxidative stability of liquid hydrocarbons, while also providing insights relevant to the formation mechanisms of tropospheric aerosol building blocks. The direct observation of highly oxygenated intermediates for the autooxidation of alkanes at 500–600 K builds upon prior observations made in atmospheric conditions for the autooxidation of terpenes and other unsaturated hydrocarbons; it shows that highly oxygenated intermediates are stable at conditions above room temperature. These results further reveal that highly oxygenated intermediates are not only accessible by chemical activation but also by thermal activation. Theoretical calculations on H-atom migration reactions are presented to rationalize the relationship between the organic compound’s molecular structure (n-alkane,more » branched alkane, and cycloalkane) and its propensity to produce highly oxygenated intermediates via extensive autooxidation of hydroperoxyalkylperoxy radicals. In conclusion, detailed chemical kinetic simulations demonstrate the influence of these additional reaction pathways on the ignition of practical fuels.« less
Authors:
ORCiD logo [1] ;  [2] ;  [1] ;  [3] ;  [1] ;  [1] ;  [4] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ; ORCiD logo [1]
  1. King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia). Clean Combustion Research Center
  2. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Sciences Division; Univ. of Central Florida, Orlando, FL (United States). Dept. of Chemistry
  3. Sandia National Lab. (SNL-CA), Livermore, CA (United States). Combustion Research Facility; Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)
  4. King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia). Analytical Core Lab.
  5. Bielefeld Univ., Bielefeld (Germany). Dept. of Chemistry
  6. Sandia National Lab. (SNL-CA), Livermore, CA (United States). Combustion Research Facility
  7. Centre National de la Recherche Scientifique (CNRS), Orleans (France). Inst. National des Sciences de l'Ingenierie et des Systemes, Inst. de Combustion, Aerothermique, Reactivite et Environnement
  8. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Sciences Division
Publication Date:
Grant/Contract Number:
AC02-05CH11231; 291049-2GCSafe
Type:
Accepted Manuscript
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 114; Journal Issue: 50; 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); European Research Council (ERC); King Abdullah University of Science and Technology, Office of Sponsored Research (OSR)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1432232