Products of the gas-phase reaction of the OH radical with 3-methyl-1-butene in the presence of NO

✍ Scribed by Roger Atkinson; Ernesto C. Tuazon; Sara M. Aschmann

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 206 KB
• Volume: 30
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/(sici)1097-4601(1998)30:8<577::aid-kin7>3.0.co;2-p

✦ Synopsis

The products of the gas-phase reaction of the OH radical with 3-methyl-1-butene in the presence of NO have been investigated at room temperature and total pressure 740 torr of air by gas chromatography with flame ionization detection, in situ Fourier transform infrared absorption spectroscopy, and direct air sampling atmospheric pressure ionization tandem mass spectrometry. The products identified and quantified by GC-FID and in situ FT-IR absorption spectroscopy were HCHO, 2-methylpropanal, acetone, glycolaldehyde, and methacrolein, with formation yields of and 0.70 Ϯ 0.06, 0.58 Ϯ 0.08, 0.17 Ϯ 0.02, 0.18 Ϯ 0.03, respectively. In addition, IR absorption bands due to organic nitrates were 0.033 Ϯ 0.007, observed, consistent with API-MS observations of product ion peaks attributed to the ␤-hydroxynitrates (CH 3 ) 2 CHCH(ONO 2 )CH 2 OH and/or (CH 3 ) 2 CHCH(OH)CH 2 ONO 2 formed from the reactions of the corresponding ␤-hydroxyalkyl peroxy radicals with NO. A formation yield of ca. 0.15 for these nitrates was estimated using IR absorption band intensities for known organic nitrates. These products account for essentially all of the reacted 3-methyl-1-butene. Analysis of the potential reaction pathways involved shows that H-atom abstraction from the allylic C9 H bond in 3-methyl-1-butene is a minor pathway which accounts for 5-10% of the overall OH radical reaction.