The chemistry of pre-ignition of n-pentane and 1-pentene

• Published in: Combustion and flame 1999-07, Vol.118 (1), p.213-220
• Main Authors: Minetti, R, Roubaud, A, Therssen, E, Ribaucour, M, Sochet, L.R
• Format: Article
• Language: English
• Subjects: Applied sciences; Combustion of liquid fuels; Combustion. Flame; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Theoretical studies. Data and constants. Metering
• ISSN: 0010-2180; 1556-2921
• DOI: 10.1016/S0010-2180(98)00151-5

The pre-autoignition chemistry of n-pentane and 1-pentene was studied by rapid compression in the low temperature range (600–900 K). The pressure traces, light emissions, intensities of cool flames, autoignition delays, and hydrocarbon conversions before final ignition indicate that there are similarities of behavior, but a lower reactivity of 1-pentene over the whole temperature range. Chemical analysis of the stable intermediate species after the cool flame, but before final ignition, shows marked differences in selectivities for O-heterocycles and aldehydes. Relatively high amounts of propyloxirane and butanal in the oxidation of 1-pentene suggest additions of oxidizing radicals to the double bond. The classical low temperature peroxidation scheme of alkanes can be applied, not only to n-pentane, but also to 1-pentene, if the higher reactivity of the allylic hydrogens and direct addition of OH and HO 2 radicals are taken into account. Some peroxy radicals are common to both fuels and are responsible for their similar features of pre-autoignition chemistry. However, oxidation of 1-pentene is still deeply marked by the presence of an olefinic bond.