Publication details

Environmental Ice Photochemistry: Monochlorophenols



Year of publication 2003
Type Article in Periodical
Magazine / Source Environmental Science and Technology
MU Faculty or unit

Faculty of Science

Field Organic chemistry
Keywords ice; photochemistry; environmental; chlorophenol
Description Photolysis of 2- and 4-chlorophenol samples in water ice of the initial 10-4 to 10-2 mol l-1 concentrations is reported. Major phototransformations appeared to be based on the coupling reactions due to chlorophenol aggregation at the grain boundaries of the polycrystalline state. The main products, chlorobiphenyldiols, belong to the family of phenolic halogenated compounds (such as hydroxylated polychlorobiphenyls) that are known xenobiotics found in nature. No photosolvolysis products, that is products from intermolecular reactions between organic and water molecules, were observed at temperatures below -10 oC. Raising the temperature to -5 oC caused a moderate photosolvolytic activity in case of 4-chlorophenol (formation of hydroquinone), in contrast to 2-chlorophenol that was almost exclusively transformed into pyrocatechol. It is suggested that photosolvolysis above this temperature occurs in a quasi-liquid layer that covers the ice crystal surfaces. The results support our model in which significant amount of some persistent, bioaccumulative, and toxic compounds may be generated by photochemistry of primary pollutants in cold ecosystems and in the upper atmosphere, and may subsequently be released to the environment.
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