OXIDATION REACTIONS OF N-HEPTANE AND ISOO CTANE

The oxidation mechanisms of two alkanes that have quite different octa ne numbers: n-heptane (0) and isooctane (100), were investigated to ob tain a better understanding of the chemical mechanism of autoignition phenomena and to improve the compatibility of the available fuels with the engines. The experimental study was performed at 923 K in a setup equipped with a jet-stirred reactor. The oxidation mechanisms of n-he ptane and isooctane were simplified first by a purely kinetic analysis based on the product formation and then by using a software of simula tion of reaction mechanisms. The very different behaviour of these two hydrocarbons was explained by the presence, in the products of isooct ane oxidation, of alkenes, which would have an antiknock effect due to the formation of resonance-stabilized radicals.