Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 5.414 IF 5.414
  • IF 5-year value: 5.958 IF 5-year
    5.958
  • CiteScore value: 9.7 CiteScore
    9.7
  • SNIP value: 1.517 SNIP 1.517
  • IPP value: 5.61 IPP 5.61
  • SJR value: 2.601 SJR 2.601
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 191 Scimago H
    index 191
  • h5-index value: 89 h5-index 89
Volume 13, issue 11
Atmos. Chem. Phys., 13, 5715–5730, 2013
https://doi.org/10.5194/acp-13-5715-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
Atmos. Chem. Phys., 13, 5715–5730, 2013
https://doi.org/10.5194/acp-13-5715-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 14 Jun 2013

Research article | 14 Jun 2013

Production of methyl vinyl ketone and methacrolein via the hydroperoxyl pathway of isoprene oxidation

Y. J. Liu1, I. Herdlinger-Blatt1,2, K. A. McKinney3, and S. T. Martin1,4 Y. J. Liu et al.
  • 1School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA
  • 2Institute of Ion Physics and Applied Physics, University of Innsbruck, Innsbruck, Austria
  • 3Department of Chemistry, Amherst College, Amherst, Massachusetts, USA
  • 4Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts, USA

Abstract. The photo-oxidation chemistry of isoprene (ISOP; C5H8) was studied in a continuous-flow chamber under conditions such that the reactions of the isoprene-derived peroxyl radicals (RO2) were dominated by the hydroperoxyl (HO2) pathway. A proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) with switchable H3O+ and NO+ reagent ions was used for product analysis. The products methyl vinyl ketone (MVK; C4H6O) and methacrolein (MACR; C4H6O) were differentiated using NO+ reagent ions. The MVK and MACR yields via the HO2 pathway were (3.8 ± 1.3)% and (2.5 ± 0.9)%, respectively, at +25 °C and < 2% relative humidity. The respective yields were (41.4 ± 5.5)% and (29.6 ± 4.2)% via the NO pathway. Production of MVK and MACR via the HO2 pathway implies concomitant production of hydroxyl ((6.3 ± 2.1)%) and hydroperoxyl ((6.3 ± 2.1)%) radicals, meaning a HOx recycling of (12.6 ± 4.2)% given that HO2 was both a reactant and product. Other isoprene oxidation products, believed to be mostly organic hydroperoxides, also contributed to the ion intensity at the same mass-to-charge (m/z) ratios as the MVK and MACR product ions for HO2-dominant conditions. These products were selectively removed from the gas phase by placement of a cold trap (−40 °C) inline prior to the PTR-TOF-MS. When incorporated into regional and global chemical transport models, the yields of MVK and MACR and the concomitant HOx recycling reported in this study can improve the accuracy of the simulation of the HO2 reaction pathway of isoprene, which is believed to be the fate of approximately half of atmospherically produced isoprene-derived peroxy radicals on a global scale.

Publications Copernicus
Download
Citation