The photodegradation of pyrene (Py) in the presence of acetic acid (AA) occurs through a radical mechanism and is faster than in organic solvents (methanol). PyH• (absorption maximum in the UV/VIS spectra λmax=395 nm in AA, lifetime τ=∼2 μs in oxygen saturated solution) was identified as an intermediate in the photodegradation in AA. Absorption of a photon by ground state of Py also leads to the formation of excited states (1Py* and 3Py), which deexcite to the ground state without chemical changes. Singlet oxygen 1O2 formed by energy transfer from 3Py to dissolved oxygen does not react with Py. PyH-• and PyH+• were not found following excitation under the given conditions. The rate of photodegradation can be considerably increased by addition of water and hydrogen peroxide. The accelerating effect of hydrogen peroxide consists in photolytic formation of reactive hydroxyl radicals, which attack the pyrene nucleus.
|Number of pages||4|
|Journal||Journal of Photochemistry and Photobiology A: Chemistry|
|Publication status||Published - 20 Mar 2000|
- Laser kinetic spectroscopy
ASJC Scopus subject areas
- Chemical Engineering(all)
- Physics and Astronomy(all)