In this work, we studied the low-temperature oxidation of a stoichiometric 2-methylhexane/O2/Ar mixture in a jet-stirred reactor coupled with synchrotron vacuum ultraviolet photoionization molecular-beam mass spectrometry. The initial gas mixture was composed of 2% 2-methyhexane, 22% O2 and 76% Ar and the pressure of the reactor was kept at 780Torr. Low-temperature oxidation intermediates with two to five oxygen atoms were observed. The detection of C7H14O5 and C7H12O4 species suggests that a third O2 addition process occurs in 2-methylhexane low-temperature oxidation. A detailed kinetic model was developed that describes the third O2 addition and subsequent reactions leading to C7H14O5 (keto-dihydroperoxide and dihydroperoxy cyclic ether) and C7H12O4 (diketo-hydroperoxide and keto-hydroperoxy cyclic ether) species. The kinetics of the third O2 addition reactions are discussed and model calculations were performed that reveal that third O2 addition reactions promote 2-methylhexane auto-ignition at low temperatures. © 2016 The Combustion Institute.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was supported by: King Abdullah University of Science and Technology (KAUST) and Saudi Aramco under the FUELCOM program; National Key Scientific Instruments and Equipment Development Program of China2012YQ22011305; Department of Energy Gas Phase Chemical Physics Program at Lawrence Berkeley National LaboratoryDEAC02-05CH11231; German DFG ProjectKo1363/31-1; European Research Council under FP7/2007-2013/ERC Grant 291049-2G-CSafe; Sandia Corporation, a Lockheed Martin Company, and under National Nuclear Security Administration Contract DE-AC04-94-AL85000. The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract no. DEAC02-05CH11231.