Butanol, an alcohol which can be produced from biomass sources, has received recent interest as an alternative to gasoline for use in spark ignition engines and as a possible blending compound with fossil diesel or biodiesel. Therefore, the autoignition of the four isomers of butanol (1-butanol, 2-butanol, iso-butanol, and tert-butanol) has been experimentally studied at high temperatures in a shock tube, and a kinetic mechanism for description of their high-temperature oxidation has been developed. Ignition delay times for butanol/oxygen/argon mixtures have been measured behind reflected shock waves at temperatures and pressures ranging from approximately 1200 to 1800 K and 1 to 4 bar. Electronically excited OH emission and pressure measurements were used to determine ignition-delay times. The influence of temperature, pressure, and mixture composition on ignition delay has been characterized. A detailed kinetic mechanism has been developed to describe the oxidation of the butanol isomers and validated by comparison to the shock-tube measurements. Reaction flux and sensitivity analysis illustrates the relative importance of the three competing classes of consumption reactions during the oxidation of the four butanol isomers: dehydration, unimolecular decomposition, and H-atom abstraction. Kinetic modeling indicates that the consumption of 1-butanol and iso-butanol, the most reactive isomers, takes place primarily by H-atom abstraction resulting in the formation of radicals, the decomposition of which yields highly reactive branching agents, H atoms and OH radicals. Conversely, the consumption of tert-butanol and 2-butanol, the least reactive isomers, takes place primarily via dehydration, resulting in the formation of alkenes, which lead to resonance stabilized radicals with very low reactivity. To our knowledge, the ignition-delay measurements and oxidation mechanism presented here for 2-butanol, iso-butanol, and tert-butanol are the first of their kind.

This paper presents an experimental and modeling study of the oxidation of large linear akanes (from C 10 ) representative from diesel fuel from low to intermediate temperature (550-1100 K) including the negative temperature coefficient (NTC) zone. The experimental study has been performed in a jet-stirred reactor at atmospheric pressure for n-decane and a n-decane/n-hexadecane blend. Detailed kinetic mechanisms have been developed using computer-aided generation (EXGAS) with improved rules for writing reactions of primary products. These mechanisms have allowed a correct simulation of the experimental results obtained. Data from the literature for the oxidation of n-decane, in a jet-stirred reactor at 10 bar and in shock tubes, and of n-dodecane in a pressurized flow reactor have also been correctly modeled. A considerable improvement of the prediction of the formation of products is obtained compared to our previous models. Flow rates and sensitivity analyses have been performed in 1 * E-Mail : Frederique.Battin-Leclerc@ensic.inpl-nancy.fr, Tel : 33 3 83175125, Fax : 33 3 83378120 order to better understand the influence of reactions of primary products. A modeling comparison between linear alkanes for C 8 to C 16 in terms of ignition delay times and the formation of light products is also discussed.

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.