Kinetics of the gas-phase reactions of OH radicals with a series of trimethylphenols

The kinetics of the reactions of hydroxyl (OH) radicals with 2,3,5-trimethylphenol (235TMP), 2,3,6-trimethylphenol (236TMP), 2,4,5-trimethylphenol (245TMP), 2,4,6-trimethylphenol (246TMP), and 3,4,5-trimethylphenol (345TMP) have been investigated at 298 +/- 2 K and atmospheric pressure of air using a relative rate method. The experiments were performed in a 1080 L volume photoreactor using in situ FTIR analysis to monitor the decay of the trimethylphenols and the reference compounds. The following rate coefficients (in cm3 molecule-1 s-1) were obtained at 298 +/- 2 K and 1 atm of air: k(235TMP) = (1.48 +/- 0.42) x 10-10; k(236TMP) = (1.35 +/- 0.39) x 10-10; k(245TMP) = (1.23 +/- 0.48) x 10-10; k(246TMP) = (1.67 +/- 0.48) x 10-10; k(345TMP) = (1.55 +/- 0.43) x 10-10. The present kinetic data are discussed in terms of OH addition reactivity trends, and comparisons are made with the reactivity trends observed for successive methylation of benzene and phenol and successive hydroxylation of benzene. (C) 2011 Wiley Periodicals, Inc. Int J Chem Kinet 44: 117124, 2012