Reactivity of p-substituted benzaldoximes in the cleavage of p-nitrophenyl acetate: Kinetics and Mechanism

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22310%2F04%3A00012342" target="_blank" >RIV/60461373:22310/04:00012342 - isvavai.cz</a>
Alternative codes found
RIV/00216275:25310/04:00003452
Result on the web
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DOI - Digital Object Identifier
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Result language
angličtina
Original language name
Reactivity of p-substituted benzaldoximes in the cleavage of p-nitrophenyl acetate: Kinetics and Mechanism
Original language description
Eleven p-substituted benzaldoximes (p-XC6H4CH=NOH where X = H, CH3, CF3, F, Cl, Br, OCH3, N(CH3)2, COOCH3, CN, NO2) have been synthesized and their dissociation constants determined in 10% (v/v) aqueous dioxane at 35 °C. Under the same conditions, the pseudo-first order rate constants kobs of their reactions with p-nitrophenyl acetate (PNPA) were measured at pH values from 7.8 to 10.8 and at concentrations coxime ranging from zero to 4.00#10-4 mol l-1. The kinetic model and mechanism of the said reaction was proposed by means of mathematical statistical modelling of the dependences of kobs on pH and coxime. The mechanism involves a pre-equilibrium (k-1/k1) in which PNPA forms a tetrahedral intermediate (THI) with the deprotonated form of oxime. In thegiven medium, THI is in equilibrium with the non-reactive conjugated acid THIH (dissociation constant Ka,THIH) which is stabilized by intramolecular hydrogen bond. Depending on pH, the rate-limiting step consists either in formation of TH
Czech name
Reaktivita p-substituovaných benzaldoximů při štěpení p-nitrofenyl-acetátu: Kinetika a mechanismus
Czech description
Reaktivita p-substituovaných benzaldoximů při štěpení p-nitrofenyl-acetátu: Kinetika a mechanismus

Type
J<sub>x</sub> - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)
CEP classification
CC - Organic chemistry
OECD FORD branch
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Project
<a href="/en/project/GA203%2F01%2F1093" target="_blank" >GA203/01/1093: The effect of electron distribution on the oxime reactivity towards esters</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year
2004
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

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