PRODUCTION OF POLYCYCLIC AROMATIC-HYDROCARBONS IN CHLORINE CONTAINING ENVIRONMENTS

The factors affecting the formation and growth of polycyclic aromatic hydrocarbons (PAHs) in chlorine-containing environments are investigated. The experimental results obtained in shock-tube pyrolysis of chlorinated C, and C2 hydrocarbons are re-analyzed in terms of CI-to-H molar ratio of the mixture and it is found that the sooting tendency and hence PAH production are increased with the increase in [Cl]/[H] ratio. Based on the analysis of the reaction kinetics and results of detailed modeling, two basic factors are suggested to be responsible for this phenomenon: (l) the enhanced, chlorine-catalized molecular degradation that promotes the formation of aromatic-ring compounds; and (2) the large concentration of Cl atoms that accelerates the abstraction of aromatic H from stable PAH molecules, which activates them for further growth. The modeling results also provide an evidence against existence of a correlation between PAHs and CO in flame environments. © 1990, Taylor & Francis Group, LLC. All rights reserved.