Quantum mechanic study of high molecular mass compounds in combustion conditions

Experimental studies on soot formation show interesting trends that can only be explained by a polymerization pathway. These experimental findings are reviewed and ab initio calculations are used to evaluate possible mechanistic pathways. A sequence of chemical reactions between aromatic compounds and compounds containing conjugated double bonds was studied in detail. The reactions analyzed represent a first possible propagation step of a sequence that can be easily repeated for the formation of high molecular mass compounds. The distinguishing features of the proposed model lie in the chemical specificity of the routes proposed. The aromatic radical attacks the double bond of five-membered ring PAH giving addition reactions. This is allowed by specific compounds that are exceptional monomers as they form resonantly stabilized radical intermediates, relieving part of the large strain in the five-membered rings by linear polymer formation.