Gas-phase reaction of hydroxyl radicals with m-, o-, and p-cresol

The gas-phase reaction of oxygenated aromatic compounds m-cresol, o-cresol, and p-cresol with hydroxyl radicals has been studied by GC-MS. Experiments have been performed in a large-volume photoreactor (8000 L) at 294 2 K and atmospheric pressure. The relative kinetic method was used to determine the rate constants for these reactions, with 1,3,5-trimethylbenzene as a reference compound. The rate constants obtained are k(OH)(M-cresol)=(5.88 +/- 0.92) x 10(-11) cm(3) molecule(-1) s(-1), k(OH)(o-cresol)=(4.32 +/- 0.52) x 10(-11) cm(3) molecule(-1) s(-1), and k(OH)(p-cresol)=(4.96 +/- 0.75) x 10(-11) cm(3) molecule(-1) s(-1). The degradation products observed and their respective molar yields were methyl-1,4-benzoquinone 12.4 +/- 1.2%, 5-methyl-2-nitrophenol 1.5 +/- 0.3%, and 3-methyl-2-nitrophenol 1.4 +/- 0.3% from m-cresol, methyl-1, 4-benzoquinone 5.6 +/- 0.9%, and 6-methyl-2-nitrophenol 4.7 +/- 0.8% from o-cresol, and 4-methyl-2-nitrophenol 17.2 +/- 2.5% from p-cresol. This kinetic and product data are compared with the literature, and the reaction mechanisms are discussed. Our results are in accordance with the previous studies (Atkinson, I Phys Chem Ref Dato 1989, Monograph (1), 1-246; Atkinson and Aschmann, Int I Chem Kinet 1990, 22, 59-67; Atkinson et al., Environ Sci Technot 1992, 26, 1397-1403; Atkinson et al., J Phys Chem 1978, 82, 2759-2805; Olariu et al., Atmos Environ 2002, 36, 3685-3697; Semadeni et al., Int I Chem Kinet 1995, 27, 287-304) and confirm the methyl-1,4-benzoquinone yields determined by a different experimental technique (long-path Fourier transform infrared FT-IR (Olariu et al., 2002)). (c) 2006 Wiley Periodicals, Inc.