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KMID : 1024520060150050485
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Journal of the Environmental Sciences
2006 Volume.15 No. 5 p.485 ~ p.491
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Dephosphorylation of an Organic Phosphinate by Nucleophile in Anionic and Cationic Micellar Solutions
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Kim Jeung-Bae
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Abstract
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In the aqueous solutions the dephosphorylations of isopropyl phenyl-4-nitrophenyl phosphinate(IPNPIN) mediated by hydroxide and o-iodosobenzoate ions ate relatively slow, because of hydrophobicity of the substrate, and however it appears that is inherently better nucleophile than , which is more soft ion. On the other hand, in cetyltrimetyiammonium bromide(CTABr) solutions which contain cationic micelles, the dephosphorylations of IPNPIN mediated by or ate very accelerated to 120 or 100,000 times as compared with those in the aqueous solutions. The values of pseudo first order rate constants reach a maximum with increasing. Such rate maxima are typical of micellar catalysed bimolecular reactions and the rise in rate constant followed by a gradual decrese is characteristic of reactions of hydrophobic substrates. In the cationic micellar solutions of CTABr, accelerates the reactions much more than that does. The reason seems that which is more hydrophobic and soft ion than is more easily moved into the Stern layer of the CTABr micelles than . In the anionic micellar solutions of sodium dodecyl sulfate(SDS), the dephosrhorylations of IPNPIN ate slower than those in aqeous solutions. It means that or cannot easily move and approach to the Stern layer of the micelle in which almost all the hydrophobic substrate are located and which has a negative circumstance.
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KEYWORD
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Dephosphorylation, CTABr, SDS, Micelle
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