Theoretical study of important phenylacetylene reactions in polycyclic aromatic hydrocarbon growth

Qian Mao*, Luna Pratali Maffei, Heinz Pitsch, Tiziano Faravelli

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Phenylacetylene is of significance in polycyclic aromatic hydrocarbon (PAH) growth in combustion systems, especially as the key intermediate species in the hydrogen abstraction carbon addition sequence. The consumption of phenylacetylene via H-atom abstraction reactions forming ortho-C6H4C2H (o-C6H4C2H) radical and its subsequent reaction with carbon addition are important steps in PAH growth. Nevertheless, rate constants for H-atom abstraction reactions from phenylacetylene have not been explored theoretically in the literature. As regards carbon addition, besides acetylene, ethylene is also presented in large concentrations in e.g., ethylene and propene flames. However, its role in PAH growth has not been well addressed yet. In this study, the H-atom abstraction reactions from phenylacetylene aromatic ring sites (ortho-, meta-, para-) by both H atoms and OH radicals, and the subsequent C2H4 addition to o-C6H4C2H radical are accurately determined with electronic structure calculations. The main bimolecular product from the potential energy surface of the C2H4 addition to o-C6H4C2H is 2-ethynylstyrene + H, while naphthalene + H and 1-methyleneindene + H are preferred to form at high temperatures and low pressures. Rate constants are lumped with an automated master equation-based lumping approach and integrated into a recently developed chemical kinetic model. Updates of the phenylacetylene-related reactions are tested by ethylene and benzene copyrolysis in shock tube, and ethylene oxidation in laminar premixed and counterflow diffusion flames. Reaction flux analysis are additionally performed regarding the phenylacetylene consumption and naphthalene formation.

Original languageEnglish
Article number113300
JournalCombustion and Flame
Volume261
DOIs
Publication statusPublished - Mar 2024

Keywords

  • Chemical kinetics
  • Ethylene
  • H-atom abstraction
  • Naphthalene
  • Phenylacetylene

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