Gas‐phase reaction of hydroxyl radicals withm‐,o‐ andp‐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) × 10 −11 cm 3 molecule −1 s −1 , k OH ( o ‐cresol) = (4.32 ± 0.52) × 10 −11 cm 3 molecule −1 s −1 , and k OH ( p ‐cresol) = (4.96 ± 0.75) × 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, J Phys Chem Ref Data 1989, Monograph (1), 1–246; Atkinson and Aschmann, Int J Chem Kinet 1990, 22, 59–67; Atkinson et al., Environ Sci Technol 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 J 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)).