Environmental Science & Technology 2011-01-15

Air pollutants formed in thermal decomposition of folpet fungicide under oxidative conditions.

Kai Chen, John C Mackie, Eric M Kennedy, Bogdan Z Dlugogorski

Index: Environ. Sci. Technol. 45(2) , 554-60, (2011)

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Abstract

This contribution studies the decomposition of folpet fungicide under oxidative conditions and compares the product species with those of captan fungicide, which is structurally related to folpet. Toxic products arising from folpet comprised carbon disulfide (highest emission factor of 4.9 mg g(-1) folpet), thiophosgene (14.4), phosgene (34.1), hydrogen cyanide (2.6), tetrachloroethylene (111), hexachloroethane (167), and benzonitrile (4.5). Owing to their related molecular structures, folpet emitted similar products to captan but at different yields, under the same experimental conditions. It appears that the availability of easily abstractable H atoms, in the structure of captan but not in that of folpet, defines the product distribution. In conjunction with the quantum chemical calculations, these experimental measurements afford an enhanced explanation of the formation pathways of hazardous decomposition products of these two structurally related fungicides.