Photochemistry of halogenated benzene derivatives. Part IX. environmental aquatic phototransformation of bromoxynil (3,5-dibromo-4-hydroxybenzonitrile)

摘要: Photochemistry of the herbicide 3,5-dibromo-4-hydroxybenzonitrile (bromoxynil) (I) was investigated by irradiating at approximately 313 nm. Aqueous phase photoreactions 0.078–7.800 × 10−5m solutions I were carried out different pH values. Quantum yields for loss in buffered 0.008 (±0.0004), 0.048 (±0.0024), and 0.044 (±0.0022) 2.6, 7.0, 11.0, respectively. In neutral basic conditions, absorbed more strongly wavelengths > 290 nm, an environmentally significant region. Phototransformation monitored HPLC UV-VIS spectrometry. All gave rise to generation two products, 3-bromo-4-hydroxybenzonitrile 4-hydroxybenzonitrile. The former photoproduct tentatively identified from its mass spectral data. photoproducts can be accounted with a proposed mechanism involving free radicals.