Photodegradation of the herbicide penoxsulam in aqueous methanol and acetonitrile.
Penoxsulam is a triazolopyrimidine sulfonamide group of rice herbicide. The phototransformation of penoxsulam was studied under UV light (lambda max >or= 290 nm) and sunlight in aqueous methanol and acetonitrile solvent system using TiO2 as sensitizer. The rate of photodegradation of penoxsulam in different solvent systems followed first-order kinetics and calculated half-lives was found to be in the range of 51.89-73.41 h and 62.70-97.09 h for UV light and sunlight respectively in the presence or absence of sensitizer. From this study, a total of six photoproducts were identified and characterized on the basis of Q-Tof micromass spectral data. The plausible mechanism of phototransformation involved were hydrolysis, photo oxidation of the sulfonamide group, breaking of sulfonamide bond, loss of amino and sulfonic acid group.
Pramanik
Sukhendu K
SK
Pesticide Residue Laboratory, Department of Agricultural Chemicals, Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India. skpramanik@gmail.com
Das
Saktipada
S
Bhattacharyya
Anjan
A
D000097:Acetonitriles / Q000737:chemistry*; D006540:Herbicides / Q000737:chemistry*; D007700:Kinetics; D000432:Methanol / Q000737:chemistry*; D010084:Oxidation-Reduction; D010777:Photochemistry; D013449:Sulfonamides / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry; D014466:Ultraviolet Rays; D014529:Uridine / Q000031:analogs & derivatives* / Q000737:chemistry; D014867:Water / Q000737:chemistry*
D000097:Acetonitriles; D006540:Herbicides; D013449:Sulfonamides; D014867:Water; C009495:titanium dioxide; C504402:penoxsulam; D014025:Titanium; D014529:Uridine; D000432:Methanol; C032159:acetonitrile