title: Branching fractions of the CN + C3H6 reaction using synchrotron photoionization mass spectrometry: evidence for the 3-cyanopropene product.
abstract: The gas-phase CN + propene reaction is investigated using synchrotron photoionization mass spectrometry (SPIMS) over the 9.8-11.5 eV photon energy range. Experiments are conducted at room temperature in 4 Torr of He buffer gas. The CN + propene addition reaction produces two distinct product mass channels, C(3)H(3)N and C(4)H(5)N, corresponding to CH(3) and H elimination, respectively. The CH(3) and H elimination channels are measured to have branching fractions of 0.59 ± 0.15 and 0.41 ± 0.10, respectively. The absolute photoionization cross sections between 9.8 and 11.5 eV are measured for the three considered H-elimination coproducts: 1-, 2-, and 3-cyanopropene. Based on fits using the experimentally measured photoionization spectra for the C(4)H(5)N mass channel and contrary to the previous study (Int. J. Mass. Spectrom.2009, 280, 113-118), where it was concluded that 3-cyanopropene was not a significant product, the new data suggests 3-cyanopropene is produced in significant quantity along with 1-cyanopropene, with isomer branching fractions from this mass channel of 0.50 ± 0.12 and 0.50 ± 0.24, respectively. However, similarities between the 1-, 2-, and 3-cyanopropene photoionization spectra make an unequivocal assignment difficult based solely on photoionization spectra. The CN + CH(2)CHCD(3) reaction is studied and shows, in addition to the H-elimination product signal, a D-elimination product channel (m/z 69, consistent with CH(2)CHCD(2)CN), providing further evidence for the formation of the 3-cyanopropene reaction product.
authors: School of Chemistry, University of Wollongong, NSW, Australia. adamt@uow.edu.au
authors: Adam J
authors: AJ
authors: Trevitt
authors: Satchin
authors: S
authors: Soorkia
authors: John D
authors: JD
authors: Savee
authors: Talitha S
authors: TS
authors: Selby
authors: David L
authors: DL
authors: Osborn
authors: Craig A
authors: CA
authors: Taatjes
authors: Stephen R
authors: SR
authors: Leone
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D003486:Cyanides / Q000737:chemistry*; D013058:Mass Spectrometry; D009570:Nitriles / Q000138:chemical synthesis* / Q000737:chemistry; D055668:Photochemical Processes; D011407:Propane / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D017356:Synchrotrons
chemical_list: C570415:3-cyanopropene; D000475:Alkenes; D003486:Cyanides; D009570:Nitriles; C013658:propylene; D011407:Propane