Functionalized Hydroperoxide Formation from the Reaction of Methacrolein-Oxide, an Isoprene-Derived Criegee Intermediate, with Formic Acid: Experiment and Theory
Michael F. Vansco,
Kristen Zuraski,
Frank A. F. Winiberg,
Kendrew Au,
Nisalak Trongsiriwat,
Patrick J. Walsh,
David L. Osborn,
Carl J. Percival,
Stephen J. Klippenstein,
Craig A. Taatjes,
Marsha I. Lester,
Rebecca L. Caravan
Affiliations
Michael F. Vansco
Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
Kristen Zuraski
NASA Postdoctoral Program Fellow, NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
Frank A. F. Winiberg
NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
Kendrew Au
Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA 94551, USA
Nisalak Trongsiriwat
Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
Patrick J. Walsh
Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
David L. Osborn
Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA 94551, USA
Carl J. Percival
NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
Stephen J. Klippenstein
Argonne National Laboratory, Chemical Sciences and Engineering Division, Lemont, IL 60439, USA
Craig A. Taatjes
Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA 94551, USA
Marsha I. Lester
Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
Rebecca L. Caravan
Argonne National Laboratory, Chemical Sciences and Engineering Division, Lemont, IL 60439, USA
Methacrolein oxide (MACR-oxide) is a four-carbon, resonance-stabilized Criegee intermediate produced from isoprene ozonolysis, yet its reactivity is not well understood. This study identifies the functionalized hydroperoxide species, 1-hydroperoxy-2-methylallyl formate (HPMAF), generated from the reaction of MACR-oxide with formic acid using multiplexed photoionization mass spectrometry (MPIMS, 298 K = 25 °C, 10 torr = 13.3 hPa). Electronic structure calculations indicate the reaction proceeds via an energetically favorable 1,4-addition mechanism. The formation of HPMAF is observed by the rapid appearance of a fragment ion at m/z 99, consistent with the proposed mechanism and characteristic loss of HO2 upon photoionization of functional hydroperoxides. The identification of HPMAF is confirmed by comparison of the appearance energy of the fragment ion with theoretical predictions of its photoionization threshold. The results are compared to analogous studies on the reaction of formic acid with methyl vinyl ketone oxide (MVK-oxide), the other four-carbon Criegee intermediate in isoprene ozonolysis.
