Chemistry of the Formation of PAHs and Soot Particles from Combustion (1)

Abstract

The structures and thermodynamic aspects of the PAHs and soot emitted from combustion as well as their formation processes in high-temperature environment are briefly reviewed and introduced. Firstly, the morphology of the soot and the mechanism of formation inferred from the macro- and microstructures and chemical analyses are described. Then the chemical structures and the stability of the PAHs based on the π-resonance electronic structures in termed of the Kekulé count and the Pauling bond order are discussed. The thermodynamic aspect of the soot formation is explained based on the overall combustion equilibrium state, and the thermodynamics governing the microscopic equilibrium between key intermediate species is introduced for the understanding of the temperature-limiting phenomena. Finally the coagulation step of the graphene platelets to graphite crystallite is discussed based on the thermodynamics of the elementary processes.