• Journal of Environmental Science International
• /
• v.14 no.2
• /
• pp.241-249
• /
• 2005

This study deals with micellar effects on dephosphorylation of diphenyl-4- nitrophenylphosphate (DPNPPH), diphenyl-4-nitrophenylphosphinate (DPNPlN) and isopropylphenyl-4-nitrophenyl phosphinate (IPNPlN) mediated by $OH^\Theta$ or o-iodosobenzoate ion $(IB^\Theta)$ in aqueous and CTAX solutions. Dephosphorylation of DPNPPH, DPNPIN and IPNPIN mediated by $OH^\Theta$ or o-iodosobenzoate ion $(IB^\Theta)$ is relatively slow in aqueous solution. The reactions in CTAX micellar solutions are, however, much accelerated because CTAX micelles can accommodate both reactants in their Stem layer in which they can easily react, while hydrophilic $OH^\Theta\;(or\;IB^\Theta)$ and hydrophobic substrates are not mixed in water. Even though the concentrations $(>10^{-3}\;M)\;of\;OH^\Theta\;(or\;IB^\Theta)$ in CTAX solutions are much larger amounts than those $(6\times10^{-6}\;M)$ of substrates, the rate constants of the dephosphorylations are largely influenced by the change of concentration of the ions, which means that the reactions are not followed by the pseudo first order kinetics. In comparison to effect of the counter ions of CTAX in the reactions, CTACI is more effective on the dephosphorylation of substrates than CTABr due to easier expelling of $Cl^\Theta$ ion by $OH^\Theta\;(or\;IB^\Theta)$ ion from the micelle, because of easier solvation of $Cl^\Theta$ ion by water molecules. The reactivity of IPNPlN with $OH^\Theta\;(or\;IB^\Theta)$ is lower than that of DPNPlN. The reason seems that the 'bulky' isopropyl group of IPNPIN hinders the attack of the nucleophiles.

• The Korean Journal of Pesticide Science
• /
• v.2 no.3
• /
• pp.117-125
• /
• 1998

Flupyrazofos (O,O-diethyl-O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl)thiophosphoric acid ester) is a new organo-phosphorous insecticide. Flupyrazofos has exhibited excellent activity against diamondback moth (Plutella xylostella, DBM), and it is highly activity against rice armyworm(Pseudaleta separata) and cotton caterpillar(Palpita indicae). Flupyrazofos has then revealed outstanding both rapidity and residual action for DBM, although no systemic actions were observed and no cross-resistances were found to the resistance strains (Op-R, Py-R, IGR-R). Also, susceptibilities of five local strains to flupyrazofos were similar to those of the susceptible strain. These results indicate that flupyrazofos has considerable potential for controlling diamondback moth, rice armyworm and cotton caterpillar in field.