Gas chromatographic-mass spectrometric study of photodegradation of carbamate pesticides.
The photodegradation of seven carbamate pesticides (bendiocarb, isoprocarb, promecarb, ethiofencarb, furathiocarb, fenoxycarb and pirimicarb), in aqueous solution, has been examined by GC-MS. The most general result was formation of the corresponding phenols. Irradiation of isoprocarb and promecarb also resulted in photo-Fries rearrangement to ortho- and para-hydroxybenzamides. In the case of ethiofencarb photocleavage of the carbon-sulfur bond gave 2-methylphenyl methylcarbamate as main product. Likewise, N-S bond cleavage occurred upon irradiation of furathiocarb, to allow the formation of the carbamate insecticide carbofuran, butyl methylcarbamate and carbofuranphenol. Under similar conditions, fenoxycarb gave p-phenylphenol and 2-hydroxydibenzofuran, through primary homolysis of the aryloxy-methylene bond. Finally, pirimicarb gave rise to 2-formylamino-5,6-dimethylpyrimidin-4-yl dimethylcarbamate.
Climent
M J
MJ
Departamento de Química, Universidad Politécnica de Valencia, Spain.
Miranda
M A
MA
D002219:Carbamates; D008401:Gas Chromatography-Mass Spectrometry; D007306:Insecticides / Q000737:chemistry*; D010777:Photochemistry
D002219:Carbamates; D007306:Insecticides