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Five vs. six membered-ring PAH products from reaction of o-methylphenyl radical and two C3H4 isomers
- Source :
- Physical Chemistry Chemical Physics. 23:14913-14924
- Publication Year :
- 2021
- Publisher :
- Royal Society of Chemistry (RSC), 2021.
-
Abstract
- Gas-phase reactions of the o-methylphenyl (o-CH3C6H4) radical with the C3H4 isomers allene (H2C[double bond, length as m-dash]C[double bond, length as m-dash]CH2) and propyne (HC[triple bond, length as m-dash]C-CH3) are studied at 600 K and 4 Torr (533 Pa) using VUV synchrotron photoionisation mass spectrometry, quantum chemical calculations and RRKM modelling. Two major dissociation product ions arise following C3H4 addition: m/z 116 (CH3 loss) and 130 (H loss). These products correspond to small polycyclic aromatic hydrocarbons (PAHs). The m/z 116 signal for both reactions is conclusively assigned to indene (C9H8) and is the dominant product for the propyne reaction. Signal at m/z 130 for the propyne case is attributed to isomers of bicyclic methylindene (C10H10) + H, which contains a newly-formed methylated five-membered ring. The m/z 130 signal for allene, however, is dominated by the 1,2-dihydronaphthalene isomer arising from a newly created six-membered ring. Our results show that new ring formation from C3H4 addition to the methylphenyl radical requires an ortho-CH3 group - similar to o-methylphenyl radical oxidation. These reactions characteristically lead to bicyclic aromatic products, but the structure of the C3H4 co-reactant dictates the structure of the PAH product, with allene preferentially leading to the formation of two six-membered ring bicyclics and propyne resulting in the formation of six and five-membered bicyclic structures.
- Subjects :
- chemistry.chemical_classification
Bicyclic molecule
Double bond
Allene
General Physics and Astronomy
02 engineering and technology
010402 general chemistry
021001 nanoscience & nanotechnology
Triple bond
Propyne
Ring (chemistry)
01 natural sciences
Toluene
Medicinal chemistry
0104 chemical sciences
chemistry.chemical_compound
chemistry
Physical and Theoretical Chemistry
Indene
0210 nano-technology
Subjects
Details
- ISSN :
- 14639084 and 14639076
- Volume :
- 23
- Database :
- OpenAIRE
- Journal :
- Physical Chemistry Chemical Physics
- Accession number :
- edsair.doi...........2e209c2d11eb046d2be53543f31416fa