title: Quantification of the Keto-Hydroperoxide (HOOCH2OCHO) and Other Elusive Intermediates during Low-Temperature Oxidation of Dimethyl Ether.
abstract: This work provides new temperature-dependent mole fractions of elusive intermediates relevant to the low-temperature oxidation of dimethyl ether (DME). It extends the previous study of Moshammer et al. [ J. Phys. Chem. A 2015 , 119 , 7361 - 7374 ] in which a combination of a jet-stirred reactor and molecular beam mass spectrometry with single-photon ionization via tunable synchrotron-generated vacuum-ultraviolet radiation was used to identify (but not quantify) several highly oxygenated species. Here, temperature-dependent concentration profiles of 17 components were determined in the range of 450-1000 K and compared to up-to-date kinetic modeling results. Special emphasis is paid toward the validation and application of a theoretical method for predicting photoionization cross sections that are hard to obtain experimentally but essential to turn mass spectral data into mole fraction profiles. The presented approach enabled the quantification of the hydroperoxymethyl formate (HOOCH2OCH2O), which is a key intermediate in the low-temperature oxidation of DME. The quantification of this keto-hydroperoxide together with the temperature-dependent concentration profiles of other intermediates including H2O2, HCOOH, CH3OCHO, and CH3OOH reveals new opportunities for the development of a next-generation DME combustion chemistry mechanism.
authors.affiliation: Combustion Research Facility, Sandia National Laboratories , Livermore, California 94551, United States.
authors.forename: Kai
authors.initials: K
authors.lastname: Moshammer
authors.affiliation: Combustion Research Facility, Sandia National Laboratories , Livermore, California 94551, United States.
authors.forename: Ahren W
authors.initials: AW
authors.lastname: Jasper
authors.affiliation: Department of Chemistry, University of California-Berkeley, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
authors.forename: Denisia M
authors.initials: DM
authors.lastname: Popolan-Vaida
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Clean Combustion Research Center (CCRC) , Thuwal 23955-6900, Saudi Arabia.
authors.forename: Zhandong
authors.initials: Z
authors.lastname: Wang
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Clean Combustion Research Center (CCRC) , Thuwal 23955-6900, Saudi Arabia.
authors.forename: Vijai Shankar
authors.initials: VS
authors.lastname: Bhavani Shankar
authors.affiliation: Department of Chemistry, Bielefeld University , D-33615 Bielefeld, Germany.
authors.forename: Lena
authors.initials: L
authors.lastname: Ruwe
authors.affiliation: Combustion Research Facility, Sandia National Laboratories , Livermore, California 94551, United States.
authors.forename: Craig A
authors.initials: CA
authors.lastname: Taatjes
authors.affiliation: Centre National de la Recherche Scientifique (CNRS-INSIS), ICARE, 45071 Orléans Cedex 2, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Dagaut
authors.affiliation: Combustion Research Facility, Sandia National Laboratories , Livermore, California 94551, United States.
authors.forename: Nils
authors.initials: N
authors.lastname: Hansen