Products and mechanisms of the gas-phase reactions of OH radicals and O3 with 2-methyl-3-buten-2-ol

Products of the gas-phase reactions of OH radicals (in the presence of NO) and O-3 with the biogenic organic compound 2-methyl-3-buten-2-ol have been investigated using gas chromatography with flame ionization detection (GC-FID), combined gas chromatography-mass spectrometry (GC-MS), gas chromatography with Fourier transform infrared detection (GC-FTIR), in situ FT-IR spectroscopy and in situ atmospheric pressure ionization tandem mass spectrometry (API-MS/MS). Formaldehyde, 2-hydroxy-2-methylpropanal and acetone were identified from both the OH radical and O-3 reactions, glycolaldehyde and organic nitrate (s) were also observed from the OH radical reaction, and the OH radical formation yield from the O-3 reaction was measured. The formaldehyde, 2-hydroxy-2-methylpropanal, glycolaldehyde, acetone and organic nitrate yields from the OH radical reaction were 0.29 +/- 0.03, 0.19 +/- 0.07, 0.61 +/- 0.09, 0.58 +/- 0.04 and 0.05 +/- 0.02, respectively, and the formaldehyde, 2-hydroxy-2-methylpropanal and OH radical formation yields from the O-3 reaction were 0.29 +/- 0.03, 0.30 +/- 0.06 (0.47 from FT-IR measurements) and 0.19 (uncertain to a factor of 1.5), respectively. Acetone was also observed from the O-3 reaction, but appeared to be formed from secondary reactions. Reaction mechanisms are presented and discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.