First aromatic ring formation by the radical-chain reaction of vinylacetylene and propargyl

Embargo End Date
2022-12-01

Type
Article

Authors
Jin, Hanfeng
Xing, Lili
Liu, Dapeng
Hao, Junyu
Yang, Jiuzhong
Farooq, Aamir

KAUST Department
Clean Combustion Research Center
Physical Science and Engineering (PSE) Division
Mechanical Engineering Program
Mechanical Engineering

Online Publication Date
2020-12-01

Print Publication Date
2021-03

Date
2020-12-01

Submitted Date
2020-08-14

Abstract
Recent investigations illustrated that clustering of hydrocarbons by radical-chain reaction (CHRCR) mechanism provides key mechanistic steps for the rapid synthesis of polycyclic aromatic hydrocarbons (PAHs) and soot. Resonance-stabilized radicals (RSRs) play critical roles in this mechanism, and non-benzene first-ring species have attracted considerable attention as precursors of larger aromatic hydrocarbons. C7H7 RSRs, such as benzyl, tropyl, vinyl-cyclopentadienyl, are particularly stable and are thus quite important in the growth of PAHs. The addition of vinylacetylene to propargyl radical, a prototypical CHRCR reaction, provides a facile route to C7H7 RSRs. We have directly investigated the reaction of propargyl and vinylacetylene in isomer-resolved elementary experiments by synchrotron vacuum ultra-violet photoionization molecular beam mass spectrometry (SVUV-PI-MBMS). In good agreement with theoretical predictions, vinyl-cyclopentadienyl is found to be the major product of vinylacetylene and propargyl reaction while benzyl is minor. This work demonstrates a feasible CHRCR pathway, not proceeding through benzene, for PAH formation.

Citation
Jin, H., Xing, L., Liu, D., Hao, J., Yang, J., & Farooq, A. (2021). First aromatic ring formation by the radical-chain reaction of vinylacetylene and propargyl. Combustion and Flame, 225, 524–534. doi:10.1016/j.combustflame.2020.11.034

Acknowledgements
This research was funded by the Office of Sponsored Research at King Abdullah University of Science and Technology (KAUST), and by Chinese Universities Scientific Fund, WK2310000069. Quantum calculations in this study is supported by KAUST Supercomputing Laboratory.

Publisher
Elsevier BV

Journal
Combustion and Flame

DOI
10.1016/j.combustflame.2020.11.034

Additional Links
https://linkinghub.elsevier.com/retrieve/pii/S0010218020305368

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