Unexpected Chemistry from the Reaction of Naphthyl and Acetylene at Combustion‐Like Temperatures |
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| Authors: | Dr Dorian S N Parker Prof Dr Ralf I Kaiser Dr Biswajit Bandyopadhyay Dr Oleg Kostko Dr Tyler P Troy Dr Musahid Ahmed |
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| Affiliation: | 1. Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, (USA) http://www.chem.hawaii.edu/Bil301/welcome.html;2. Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 947200, (USA) |
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| Abstract: | The hydrogen abstraction/acetylene addition (HACA) mechanism has long been viewed as a key route to aromatic ring growth of polycyclic aromatic hydrocarbons (PAHs) in combustion systems. However, doubt has been drawn on the ubiquity of the mechanism by recent electronic structure calculations which predict that the HACA mechanism starting from the naphthyl radical preferentially forms acenaphthylene, thereby blocking cyclization to a third six‐membered ring. Here, by probing the products formed in the reaction of 1‐ and 2‐naphthyl radicals in excess acetylene under combustion‐like conditions with the help of photoionization mass spectrometry, we provide experimental evidence that this reaction produces 1‐ and 2‐ethynylnaphthalenes (C12H8), acenaphthylene (C12H8) and diethynylnaphthalenes (C14H8). Importantly, neither phenanthrene nor anthracene (C14H10) was found, which indicates that the HACA mechanism does not lead to cyclization of the third aromatic ring as expected but rather undergoes ethynyl substitution reactions instead. |
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| Keywords: | combustion gas‐phase chemistry mass spectrometry polycyclic aromatic hydrocarbons radicals |
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