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Prokop’eva, T. M.; Simanenko, Yu. S.; Suprun, I. P.; Savëlova, V. A.; Zubareva, T. M.; Karpichev, Yevgen

doi:10.1023/a:1012487415041

Cited by 26 publications

(31 citation statements)

References 7 publications

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“…This conclusion is not trivial and requires confirmation over a wider range of functional detergents. The same trend arises for the reaction of acyl-containing substrates with oximate ions (with pK a > 9.0), for which the sensitivity of log k 2 w to pK a of the nucleophile is extremely low (b N » 0-0.1) [11]. This fact makes it possible to suppose that in functional detergents of types I and II the nature of solvation of the anionic center is similar to that for oximes that do not form micelles.…”

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confidence: 54%

“…The course of the reaction was monitored by spectrophotometry from the change in the absorption of the 4-nitrophenolate ion (l = 420 nm) with time on a Genesys 10 UV spectrophotometer (Thermo Electron) at 25°C. The procedure used for the kinetic experiments was described in detail in [8,11].…”

Section: Methodsmentioning

confidence: 99%

“…With variation of the position of the oximate group in the series of hydroxyiminomethyl-1-cetylpyridinium halides the variation of the observed rates of decomposition of 4-nitrophenyl diethyl phosphate corresponds likewise to the variation of the basicity of the a-nucleophilic fragment in hydroxyimino-1-methylpyridinium halides [1]. It is important to note that for oximes that are not micelle-forming compounds there is a single Brönsted relationship onto which the points for oximes containing both an imidazole ring and a pyridinium ring fit [11]. In so far as analysis of the experimental results in [1] in terms of the existing models for description of micellar effects was not made 0040-5760/08/4402-0093…”

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confidence: 99%

“…The points for the oximate ions Ia and IIa lie on the corresponding Brönsted curves for the reactions of the oximate ions with NPDEP, NPDEPS, and NPTS [11], i.e., they are typical a-nucleophiles.…”

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confidence: 99%

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Structure of the head group, nucleophilicity, and micellar effects of functional detergents in acyl transfer reactions

et al. 2008

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The micellar effects of 1-cetyl-2-methyl-3-(2-hydroxyiminopropyl)imidazolium and 1-cetyl-3-hydroxyiminomethylpyridinium halides in acyl transfer reactions (phosphoryl, phosphonyl, and toluenesulfonyl) were investigated. Variation of the nature of the head group does not lead to change in the reactivity of the oximate group, while the nucleophilicity follows the basicity of the functional fragment. The increase of the observed reaction rates during transfer of the disintegration of the substrates from water to the micellar pseudophase is due both to concentration of the reagents and to change in the reactivity of the oximate group. The new detergent 1-cetyl-2-methyl-3-(2-hydroxyiminopropyl)imidazolium chloride is one of the most effective functional surfactants in the decomposition of organophosphorus compounds. Key words: functional surfactants based on pyridine and imidazole, nucleophilicity, micellar effects.Functional surfactants containing an a-nucleophilic fragment in the head group are usually characterized both by high nucleophilic reactivity and by effective solubilization of electrically neutral polar substrates, including excotoxicants of organophosphorus type [1-10]. During the design of new functional detergents an important role is played by the true solubility of the surfactant in water, the basicity of the functional group, and its reactivity. However, the introduction of the functional fragment often leads to a decrease in the solubility of the surfactant in water [1,2,5,8]. Therefore, during study of the micellar effects of such detergents, as during their use in systems for the decomposition of excotoxicants, it is necessary to introduce an inert surfactant -a co-detergent, and this makes the system multicomponent and less attractive from the practical standpoint. The nucleophilicity of functional detergents can be predicted on the basis of the reactivity of analogs not forming micelles [1,2,[7][8][9][10]. This opens up the possibility of specific modification of the structure of the surfactant with the aim of producing compounds with the required level of nucleophilicity. This is the approach that we used during the creation of functional detergents based on imidazole [7][8][9]. With variation of the position of the oximate group in the series of hydroxyiminomethyl-1-cetylpyridinium halides the variation of the observed rates of decomposition of 4-nitrophenyl diethyl phosphate corresponds likewise to the variation of the basicity of the a-nucleophilic fragment in hydroxyimino-1-methylpyridinium halides [1]. It is important to note that for oximes that are not micelle-forming compounds there is a single Brönsted relationship onto which the points for oximes containing both an imidazole ring and a pyridinium ring fit [11]. In so far as analysis of the experimental results in [1] in terms of the existing models for description of micellar effects was not made 0040-5760/08/4402-0093

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confidence: 54%

Section: Methodsmentioning

confidence: 99%

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confidence: 99%

mentioning

confidence: 99%

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Structure of the head group, nucleophilicity, and micellar effects of functional detergents in acyl transfer reactions

et al. 2008

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“…The reactivity of the structural analogs of surfactants (Ia)-(IIIa) not forming micelles in water was determined in the usual way [11]. The increase of the observed rate of reaction of the esters with compounds (Ia)-(IIIa) with increase of pH ( Fig.…”

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confidence: 99%

Reactivity of functional detergents with a pyridine ring and an α-nucleophile fragment in the head group

et al. 2008

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Functional detergents (FD) based on pyridine and containing aldoximate, ketoximate, and hydroxamate groups were synthesized. Their reactivity in FD/CTAB comicelles toward 4-nitrophenyl 4-toluenesulfonate (NPTS), diethyl phosphate (NPDEP), and diethylphosphonate (NPDEPS) in weakly alkaline media was investigated. Functional detergents based on pyridine are effective in the decomposition of ecotoxicants; the half-lives for the transformation of the substrates into the reaction products in the presence of a functional detergent containing, for example, a ketoximate group amounts to~40 s (NPTS),~120 s (NPDEP), and~5 s (NPDEPS). By analyzing the results it was possible to establish the paths to further modification of the head group of the surfactant, i.e., by varying the structure of the oximate group at various positions of the pyridinium ring aimed at the production of low-basicity functional detergents.Functional detergents containing a heterocycle (pyridinium, imidazolium, etc.) and a fragment of an a-nucleophile in the head group are effective supernucleophilic reagents in the decomposition of phosphate esters -model analogs of pesticides, toxic warfare agents, etc. [1][2][3][4][5][6][7][8][9]. Modifications of the surfactants and the creation of new compounds were directed at the production of substances that make it possible to achieve the highest observable rates of decomposition of ecotoxicants under "mild" experimental conditions and in particular in media with acidity close to neutral. It is such compounds that are of particular interest from the practical point of view -the production of antidotes and supernucleophilic reagents that form the basis of degassing systems [1][2][3]5]. By varying the structure of the a-nucleophilic fragment it is possible to synthesize detergents in which the functional group will be fully ionized at pH £ 10.0.The present work examines the reactivity, the micellar effects of functional detergents (I)-(III), and the nucleophilicity of their methyl analogs (Ia)-(IIIa) in relation to 4-nitrophenyl diethylphosphonate (NPDEPS), diethyl phosphate (NPDEP), and 4-toluenesulfonate (NPTS). The functional detergents (II) and (III) were obtained for the first time.The direction of the investigation was chosen for the following reasons: The oximate and hydroxamate anions are typical a-nucleophiles that react anomalously quickly with organophosphorus compounds (OPC) [1][2][3][4][5][6][7][8]; oximes are widely used as antidotes, and the creation and investigation of inhibited cholinesterase reactivators based on them are currently being 292 0040-5760/08/4405-0292

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Micellar‐accelerated hydrolysis of organophosphate and thiophosphates by pyridine oximate

Kandpal

Dewangan

Nagwanshi³

et al. 2018

Int J of Chemical Kinetics

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Rate constants for the hydrolysis reaction of phosphate (paraoxon) and thiophosphate (parathion, fenitrothion) esters by oximate (pyridinealdoxime 2‐PyOx− and 4‐PyOx−) and its functionalized pyridinium surfactants 4‐(hydroxyimino) methyl)‐1‐alkylpyridinium bromide ions (alkyl = CnH2n+1, n = 10, 12, 14, 16) have been measured kinetically at pH 9.5 and 27°C in micellar media of cationic surfactants cetyltrimethylammonium bromide (CTAB) and cetylpyridinium bromide (CPB). Acid dissociation constant, pKa, of oximes has also been determined by spectrophotometric, kinetic, and potentiometric methods. The rate acceleration effects of cationic micelles have been explored. Cationic micelles of the pyridinium head group (CPB) showed a large catalytic effect than the ammonium head group (CTAB). The effects of pH, oximate concentration, and surfactants have been discussed.

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Cited by 26 publications

References 7 publications

Structure of the head group, nucleophilicity, and micellar effects of functional detergents in acyl transfer reactions

Structure of the head group, nucleophilicity, and micellar effects of functional detergents in acyl transfer reactions

Reactivity of functional detergents with a pyridine ring and an α-nucleophile fragment in the head group

Micellar‐accelerated hydrolysis of organophosphate and thiophosphates by pyridine oximate

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