PRODUCTS OF THE GAS-PHASE REACTIONS OF LINALOOL WITH OH RADICALS, NO3RADICALS, AND O-3

Linalool [(CH3)(2)C=CHCH2CH2C(CH3)(OH)CH-CH2] is a terpene derivative emitted from vegetation, including orange blossoms and certain trees a nd vegetation in the Mediterranean area. Linalool reacts rapidly in th e gas phase in the troposphere with OH radicals, NO3 radicals, and O-3 . With a calculated lifetime due to these reactions of similar to 1 h Or less. The products of these gas-phase reactions have been studied i n similar to 6500-7900-L Teflon chambers using gas chromatography, in situ Fourier transform infrared absorption spectroscopy, and direct ai r sampling atmospheric pressure ionization tandem mass spectrometry. T he products identified and their formation yields are as follows: from the OH radical reaction, acetone, 0.505 +/- 0.047; 6-methyl-5-hepten- 2-one, 0.068 +/- 0.006; 4-hydroxy-4-methyl-5-hexen-1-al (or its cycliz ed isomer), 0.46 +/- 0.11; from the NO3 radical reaction, acetone, 0.2 25 +/- 0.052; 4-hydroxy-4-methyl-5-hexen-1-al (or its cyclized isomer) , 0.191 +/- 0.051; and a non-quantified nitrooxycarbonyl; from the O-3 reaction, acetone, 0.211 +/- 0.024; 4-hydroxy-4-methyl-5-hexen-1-al ( or its cyclized isomer), 0.85 +/- 0.14; 5-ethenyldihydro-5-methyl-2(3H )-furanone, 0.126 +/- 0.025; and HCHO, 0.36 +/- 0.06. The formation ro utes to these products and the reaction mechanisms are discussed. Desp ite the complexity of linalool, a C-10-hydroxydiene, the reaction prod ucts observed and quantified account for a significant fraction of the carbon reacted (especially for the OH radical and O-3 reactions), wit h the carbon balances being 53 +/- 8% for the OH radical reaction in t he presence of NO, 20 +/- 4% (plus the non-quantified, but anticipated to be major, nitrooxycarbonyl) for the NO3 radical reaction, and 78 /- 10% for the O-3 reaction.