PHOTOCHEMICAL REACTION OF NITRO-POLYCYCLIC AROMATIC HYDROCARBONS: EFFECT BY SOLVENT AND STRUCTURE.

Photochemical degradation of 1-nitropyrene, 2-nitrofluorene, 2,7-dinitrofluorene, 6-nitrochrysene, 3-nitrofluoranthene, 5-nitroacenaphthene, and 9-nitroanthracene were examined in CHCl(3), CH(2)Cl(2), DMF, DMF/H(2)O (80/20), CH(3)CN, or CH(3)CN/H(2)O (80/20). The degradation follows mostly the 1(st) order kinetics; but a few follow 2(nd) order kinetics or undergo self-catalysis. The photodegradation rates follow the order: CHCl(3) > CH(2)Cl(2) > DMF > DMF/H(2)O > CH(3)CN > CH(3)CN/H(2)O. DMF is an exceptional solvent because 3 of the 7 compounds undergo self-catalytic reaction. 9-Nitroanthracene, which has a perpendicular nitro group, is the fastest, while the more compact 1-nitropyrene and 3-nitrofluoranthene, are the slowest degrading compounds.