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The effect of solvents and a substituent group on photooxidation of fluorene was investigated. Solutions of fluorene and its derivatives ( c = 0.25 g l −1 ) were irradiated using artificial light from a xenon lamp (100 mW/cm 2 ) and degradation (%), rate constants ( k p ), quantum yields (Φ) and half-lives ( t 1/2 ) were compared. In addition, reaction products formed in each case were analyzed and compared with those of fluorene. Photodegradation (%) for fluorene varied depending on the solvent used. Dichloromethane gave the largest rate constant (3.4 × 10 −4 s −1 ) and quantum yield (0.009). Both values decreased in the order of dichloromethane > acetonitrile > methanol > acetonitrile/water (70/30) > acetonitrile/water(50/50). The relation between the solubility of oxygen in solvent and the reactivity is described. 1-methylfluorene exhibited comparable photostability to that of fluorene, while 2-nitrofluorene showed good photostability. In case of 2-nitrofluorene, direct oxidation scarcely occurred and a replacement reaction was induced by the presence of a chlorine source. |
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