A simple catalytic hydrolysis of chloropyrifos by Zr (IV), Hf (IV) and Cu (II) in aqueous acidic medium by HPLC

The effect of tetravalent and bivalent metal ions on the hydrolysis of Chloropyrifos O,O-diethyl (O-3,5,6-trichloropyrid-2-yl) phosphorothioate have been studied in acidic medium. The metal ions used as catalyst are Zr (IV), Hf (IV) and Cu (II). The rate maxima for the catalytic hydrolysis by Zr (IV) & Hf (IV) were observed around pH value 2,where as for cu (II) ions, it is observed at pH 6. The mechanism involves the coordination of metal ion to water molecule leads to the formation of octameric metal aqua complex. This complex remains in equilibrium with metal hydroxide ion (M-OH-), nucleophiles (OH-) are also available from these cations even in acidic aqueous solutions. Therefore an interaction of sulfur of P=S group with metal ion and an intramolecular nucleophilic attack of metal bound OH- at Phosphorus atom results in P-O bond cleavage to liberate the hydrolysis product 3,5,6- trichloro 2- pyridinol. The current study will help in investigating the catalytic behaviour of tetravalent and bivalent metals towards organophosphorus compounds in varied environment

Author(s): Garima Sharma, C. P. Shinde and P. N.Pandey

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