FT-IR study of the ring-retaining products from the reaction of OH radicals with phenol, o-, m-, and p-cresol

The ring-retaining products of the OH-initiated degradation of phenol and o-. m-, and p-cresol in the presence of NO, have been investigated and their formation yields determined. The experiments were carried out in a large volume reactor at (298+/-2)K and 1000 mbar total pressure of synthetic air using FT-IR spectroscopy for the analysis of reactants and products. The products observed and their respective molar yields were: from phenol: 1,2-dihydroxybenzene (80.4+/-12.1)% 1,4-benzoquinone (3.7+/-1.2)% and 2-nitrophenol (5.8+/-1.0)%: from o-cresol: 3-methyl-1.2-dihydroxybenzene (73.4+/-14.6)%, methyl-1,4-benzoquinone (6.8+/-1.0)% and 6-methyl-2-nitrophenol (6.8+/-1.5)%, from m-cresol: 3-methyl-1.2-dihydroxybenzene (68.6+/-13.4)%, 4-methyl-1,2-dihydroxybenzene (9.7+/-2.7)%, methyl-1,4-benzoquinone (11.3+/-2.5)%, 5-methyl-2-nitrophenol (4.4+/-1.5)% and 3-methyl-2-nitrophenol (4.3+/-1.6)% and from p-cresol: 4-methyl-1, 2-dihydroxy benzene (64.1+/-11.3)% and 4-methyl-2-nitrophenol (7.6+/-2.2)%. Reaction pathways leading to the observed products are proposed and potential ramifications for the atmospheric reaction mechanisms of aromatic hydrocarbons are considered, (C) 2002 Published by Elsevier Science Ltd.