A Flow Reactor Study of the Oxidation of n-Octane and Iso-Octane

Abstract

An experimental study has heen conducted in a flow reactor on the oxidation of n-ocltane and iso-octane at 1080 K, one atmosphere pressure and equivalence ratio equal to one. It was found that (despite similar ratios of initial fuel decay) the conversion of the reaction intermediates to CO and CO_a is much slower during the oxidation of iso-octane than n-octane. Iso-octane produced primarily iso-butylene and propylene as intermediate hydrocarbons whereas n-octane oxidation resulted primarily in the formation or ethne. Both the nature of the intermediates formed from each fuel and the relative rates of oxidation of the intermediates were shown to be related to the number of primary, secondary and tertiary H atoms present in the initial fuel. The basic chemistry revealed by the flow reactor experiments is suggestive of new insights into the chemical phenomena pertinent to knock in spark ignition engines.