54
J. Kou et al. / Journal of Molecular Catalysis A: Chemical 325 (2010) 48–54
Because the active species holes are electrophiles, the reactions
between PAHs and hole are electrophilic reactions. The calculation
of fr for a hole reaction can proceed via Eq. (6).
Project of Science and Technology (2009DFA61090), the Jiangsu
Province Environmental Protection Bureau Scientific Research
Project (No. 2008005), and the National Natural Science Foundation
of China (No. 50732004) are gratefully acknowledged.
fr = ˙i(2(CHOMO)2)
ri
Appendix A. Supplementary data
In Eq. (6), r is the number of carbon atoms in i: 2s, 2px, 2py, and 2pz
orbitals. A higher fr value implies a more active position. According
to Gaussian 03 in conjunction with Eq. (6), the fr values of different
positions in PAHs were calculated and summarized in Table 3. For
PHE, the fr value in 9 and 10 positions are the highest in both ace-
tone and water, indicating that the most active positions in PHE are
9 and 10 positions. Similarly, the most active positions are 9 and
10 positions in ANT, and 7 and 12 positions in BaA. The calculated
results are in good agreement with the experimental ones, and the
photocatalytic oxidation does take place at the most active posi-
tions initially. As shown in Table 3, the fr values of 5 and 6 positions
are the highest in ACE, which suggests that 5 and 6 positions should
be the most active. Nevertheless, the experimental results display
that 1 and 2 positions in ACE are the most readily to be oxidized.
This can be explained as that the 1 and 2 positions of ACE have
sp3 orbital hybridization whereas the other positions of ACE have
sp2 orbital hybridization. Similar phenomenon was also reported
in fluorene oxidation which has different molecule hybrid orbitals
[31]. As a result, it is not accurate for molecule which has different
molecule hybrid orbitals. On the basis of aforementioned results,
it is conclusive that fr value is an effective method to predict the
active positions of PAHs without sp3 orbital hybridization.
Supplementary data associated with this article can be found, in
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Acknowledgements
Financial supports from the National Basic Research Program
of China (973 Program, 2007CB613305), China–Japan Cooperation