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1 1987, 1990; Zielinska et al., 1988, 1989a). The postulated reaction pathway involves initial OH
2 radical addition to the most reactive ring position; for example, C-3 position for fluoranthene
3 (Pitts et al., 1985a):
4
5
6
7
8
9
OH +
6
10 3
11 H OH
12 followed by N0 2 addition in the C-2 position. Subsequent elimination of water results in
13 2-nitrofluoranthene formation:
14
15
16
17
18
19
20
21 H OH HOH
22 The analogous reaction sequence for pyrene produces 2-nitropyrene (2-NP) (Pitts et al.,
23 1985a). In contrast, the electrophilic nitration reaction of fluoranthene or pyrene involving the
24 No; ion produces mainly 3-nitrofluoranthene (3-NF) from fluoranthene and 1-NP from pyrene.
25 The gas-phase reactions ofN 20 5 with naphthalene, 1- and 2-methylnaphthalene, .
26 acenaphthene, phenanthrene, anthracene, fluoranthene, and pyrene yield, in general, the same
27 nitro-PAH. isomers as the OH radical reaction but with different yields (Arey et al., 1989;
28 Sweetman et al., 1986; Atkinson et al., 1987, 1990; Zielinska et al., 1986, 1989a). For example,
29 the same 2-NF is produced from both OH radical and N 20 5 gas-phase fluoranthene reactions, but
30 the reaction with N 20 5 produces a much higher yield. The postulated reaction pathway involves
31 initial N0 3 radical addition to the most reactive position, followed by N0 2 addition to the
32 neighboring position and elimination of HN0 3 (Zielinska et al., 1986):
1
2/1198 2-39 DRAFT --DO NOT CITE OR QUOTE