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This paper describes an experimental and modeling study of the oxidation of methyl and ethyl butanoates in a shock tube. The ignition delays of these two esters mixed with oxygen and argon for equivalence ratios from 0.25 to 2 and ester concentrations of 0.5% and 1% were measured behind a reflected shock wave for temperatures from 1250 to 2000 K and pressures around 8 atm. To extend the range of studied temperatures in the case of methyl butanoate, two sets of measurements were also made in a jet-stirred reactor at 800 and 850 K, at atmospheric pressure, at residence times varying between 1.5 and 9 s and for equivalence ratios of 0.5 and 1. Detailed mechanisms for the combustion of methyl and ethyl butanoates have been automatically generated using a version of EXGAS software improved to take into account these oxygenated reactants. These mechanisms have been validated through comparison of simulated and experimental results in both types of reactor. The main reaction pathways have been derived from reaction flux and sensitivity analyses performed at different temperatures. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 226–252, 2010 [ABSTRACT FROM AUTHOR]

The oxidation of several binary mixtures 1-hexene/toluene has been investigated both in a shock tube and in a jet-stirred reactor (JSR). The self-ignition behavior of binary mixtures was compared to that of neat hydrocarbons studied under the same conditions. Furthermore, molecular species concentration profiles were measured by probe-sampling and GC/MS, FID, TCD analyses for the oxidation of the mixtures in a JSR. Experiments were carried out over the temperature range 750–1860 K. Mixtures were examined under two pressures 0.2 and 1 MPa, with 0.1% initial concentration of fuel. The equivalence ratio was varied from 0.5 to 1.5. The experiments were modeled using a detailed chemical kinetic reaction mechanism. The modeling study showed that interactions between hydrocarbons submechanisms were not limited to small reactive radicals. Other types of interactions involving hydrocarbon fragments derived from the oxidation of the fuel components must be considered. These interactions mainly consist of hydrogen abstraction reactions. For example, benzyl radical that is the major radical produced from the oxidation of toluene at high temperature can abstract hydrogen from 1-hexene and their products such as hexenyl radicals. Similarly, propyl, allyl, and hexenyl radicals that are the major radicals produced during 1-hexene oxidation at high temperature can abstract hydrogen from toluene. Improved modeling was achieved when such interaction reactions were included in the model. Good agreement between experimental and calculated data was obtained using the proposed detailed chemical kinetic scheme. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 518–538, 2007 [ABSTRACT FROM AUTHOR]

Abstract: The oxidation of several mixtures of surrogate for gasoline was studied using a jet stirred reactor and a shock tube. One representative of each classes constituting gasoline was selected: iso-octane, toluene, 1-hexene and ethyl tert-butyl ether (ETBE). The experiments were carried out in the 800–1880K temperature range, for two different initial pressures (0.2 and 1MPa), with an initial fuel molar fraction of 0.001. The equivalence ratio varied from 0.5 to 1.5. Each hydrocarbon sub-mechanism was validated using shock tube data. The full mechanism describing the surrogate fuel oxidation is constituted of the sub-mechanisms for each fuel components and by adding interaction reactions between different hydrocarbon fragments. Good agreement between the experimental results and the computations was observed under JSR and shock tube conditions. [Copyright &y& Elsevier]

Abstract: 1-Hexene ignition delay times were measured behind reflected shock waves for 0.1% fuel diluted in Ar between 1270 and 1700 K, at pressures between 0.2 and 1 MPa. 1-C6H12 ignition delay times were measured by following OH chemiluminescence emission. 1-Hexene oxidation has been investigated in the jet-stirred reactor (JSR) between 750 and 1200 K, at a pressure of 1 MPa, and 0.1% of fuel diluted in N2. In both experimental studies, three equivalence ratios, 0.5, 1, and 1.5, were investigated. Molecular species concentration profiles were obtained by sonic probe sampling and GC analyses during 1-hexene oxidation in JSR. H2, CO, CO2, CH2O, CH4, C2H4, C3H6, 1-C4H8, and 1,3-C4H6 were the major products of 1-C6H12 oxidation. All the experimental data have been compared to those calculated using a detailed chemical kinetic reaction mechanism. [Copyright &y& Elsevier]

Abstract: The auto-ignition delay times ? i of 1-C6H12/O2/Ar mixtures have been measured between 1270 and 1700K using shock tube technique for 3 equivalence ratios (? =0.5, 1, and 1.5) at a pressure of about 0.2MPa. At higher temperatures (>1400K), the logarithm of ? i varies linearly as a function of the temperature inverse for a given value of equivalence ratio. The apparent activation energy, E a, is approximately equal to 230kJmol?1. At lower temperature (<1400K), E a strongly decreases and becomes equal to about 120kJmol?1 around 1300K. A correlation between ? i , reactant concentrations, and temperature behind reflected shock waves was proposed for each temperature range. These correlations give an estimation of ? i with an accuracy better than 12%. A detailed chemical mechanism of the 1-hexene oxidation has been developed with the “EXGAS” program. The agreement between computed and measured values of ? i was correct at high temperatures (>1400K). The major channels of the chemical species fluxes have been discussed: at low temperatures, 1-hexene is mainly consumed by retro-ene reaction to give propene and, in a smaller ratio, by unimolecular decomposition to give allyl and 1-propyl radicals. At high temperature, unimolecular decomposition becomes more important than retro-ene reaction. The change in E a below 1400K is not explained by the model. The auto-ignition delay times of 1-hexene have been compared to those of other unsaturated hydrocarbons. For stoichiometric mixtures diluted by 99mol% of argon at a pressure of 200kPa, the shortest delays were obtained for 1-octene while the longest delays were obtained for propene. With iso-butene and ethylene, the delay times are closer to 1-hexene in the low temperature side and to propene in the high temperature one. [Copyright &y& Elsevier]

Abstract: Acetone ignition delay and stretch-free laminar flame speed measurements have been carried out and a kinetic model has been developed to simulate these and literature data for acetone and for ketene, which was found to be an important intermediate in its oxidation. The mechanism has been based on one originally devised for dimethyl ether and modified through validation of the hydrogen, carbon monoxide and methane sub-mechanisms. Acetone oxidation in argon was studied behind reflected shock waves in the temperature range 1340–1930 K, at 1 atm and at equivalence ratios of 0.5, 1 and 2; it is also shown that the addition of up to 15% acetone to a stoichiometric n-heptane mixture has no effect on the measured ignition delay times. Flame speeds at 298 K and 1 atm of pure acetone in air were measured in a spherical bomb; a maximum flame speed of ∼35 cm s−1 at is indicated. [Copyright &y& Elsevier]