Prediction of rate constants for the gas phase reactions of triphenylene with OH and NO3 radicals using a relative rate method in CCl4 liquid phase-system

The kinetics of CCl4 liquid-phase reactions of ten kinds of polycyclic aromatic compounds (PACs) including triphenylene (TP) with NO3 radicals have been investigated at 273 K by a relative rate method using naphthalene (NA) as a reference compound. The obtained relative reaction rates of the tested PACs to NA in CCl4 were as follows: 2.57 +/- 0.24 (acenaphthene), 2.11 +/- 0.30 (2,3-dimethylnaphthalene), 1.21 +/- 0.13 (fluoranthene), 0.56 +/- 0.07 (fluorene), 1.85 +/- 0.19 (1-methylnaphthalene), 1.77 +/- 0.12 (2-methylnaphthalene), 0.11 +/- 0.03 (1-nitronaphthalene), 1.59 +/- 0.23 (phenanthrene), 2.40 +/- 0.29 (pyrene), 0.22 +/- 0.04 (TP). TP is a semi-volatile PAC with four aromatic rings and it is chemically changed into mutagenic 2-nitrotriphenylene (2-NTP) via the gas-phase OH or NO3 radical-initiated reactions. On the basis of the relative reactivity of the PACs in the CCl4 liquid phase-system, the rate constants of the gas-phase reactions of TP with OH and NO3 radicals at 298 K were predicted to be (8.6 +/- 1.2) x 10(-12) cm(3) molecule(-1) s(-1) and (6.6 +/- 1.5) x 10(-29) [NO2] cm(3) molecule(-1) s(-1), respectively. Based on the ambient concentrations of TP and 2-NTP and the obtained rate constant for the reaction of TP with OH radicals, the atmospheric toss rate of 2-NTP was also evaluated. (C) 2012 Elsevier Ltd. All rights reserved.