SUMMARY/OVERVIEWThe removal of the high Damk6hler number assumption from modeling approaches is essential for the computational simulation of combusting flows where strong direct kinetic effects are present. Examples of relevant physical phenomena include flame extinction and relight as well as pollutant emissions. Calculation methods (e.g. LES/FMDF) aimed at including such effects are computationally demanding and simplified reaction mechanisms that represent the desired chemical features with sufficient accuracy are required. Difficulties are augmented for aviation fuels due to the wide range of fuel components and sufficiently accurate detailed surrogate mechanisms are required for the subsequent derivation of further simplifications under actual operating conditions prior to the implementation into calculation methods for turbulent flows. The present paper addresses the issue of substituted aromatics and outlines a reaction class based route to the derivation of detailed chemical kinetic mechanisms. The example given considers the toluene/l-methyl naphthalene system.