Development Of Predictive Reaction Models Of Soot Formation Soot Formation

This report summarizes the work performed at the Pennsylvania State University during the period 04/01/95-05/15/96. Two studies are included in this report, one carried out by Kazakov and Frenklach and the other by Weiner and Frenklach. The first one examined the relative importance of acetylene versus PAH's as major species influencing soot mass growth rates according to the kinetic model developed by Frenklach et al. The other is a preliminary investigation of the initial steps of a reaction pathway by which C3H3 radicals can be converted by acetylene to PAH's. In the first study two proposed mechanisms for the initial stages of soot formation were compared. One mechanism postulates that PAH deposition on the soot surface plays the major role in soot mass growth, the other that growth is dominated by the contribution of C2H2, while the PAH condensation on soot surface is negligible. A kinetic analysis was applied to experimental results and showed that they are consistent with the predictions of the acetylenic mechanism. In the second study a reaction pathway starting from C3H3 radicals and leading to an 0) aromatic radical in an acetylenic atmosphere was studied. This pathway was shown to be feasible on energetic grounds and involves a novel rearrangement from a five membered ring to a six membered aromatic ring via a tricyclic intermediate.