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Булавченко, А. И.; Podlipskaya, T. Yu.; Batishcheva, E. K.; Popova, T. L.; Torgov, V. G.

doi:10.1023/a:1024779213942

Cited by 8 publications

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“…The hydrody namic radius starts to rapidly increase before reaching the cloud point due to the formation of strongly extended micelles. The curves we obtained agree with those obtained earlier [19,20]. Noticeable is a poor precision of the results (especially in regard of light scattering intensity) in the vicinity of the cloud point, which is because of the systems being unstable.…”

Section: Results and Discussion Preparation And Characterization Of Psupporting

confidence: 81%

“…This was necessitated by the following: first, the need to determine the optimal reagent concentrations to provide a maximal product yield; and second, a relationship between the solubilization capacity, on one the hand, and micelle sizes [19] and, accordingly, the resulting particle sizes, on the other. In choosing nonionic oxyethylated surfactant (Tergitol NP 4) and solvent (n decane) to be used in synthesis, we were guided by the greater universality of and tolerance of solutions of nonionic surfactants in saturated hydro carbons toward electrolytes compared to ionic surfac tants [20]. First, we studied the solubilization capacity of a solution of Tergitol NP 4 in decane for pure water, which is the major solubilizer.…”

Section: Results and Discussion Preparation And Characterization Of Pmentioning

confidence: 99%

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Microemulstion synthesis of powders of water-soluble energy-saturated salts

Булавченко

Демидова

Podlipskaya

et al. 2012

Russ. J. Inorg. Chem.

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769Microemulsion (micellar) synthesis is a popular method and is widely used for preparing nanoparticles of metals [1], oxides [2], and sparingly soluble salts [3,4]. The advantages of this method include: (1) the ease of synthesis; (2) a narrow particle size distribution function of the product; (3) a feasibility of preparing particles of complex composition, multilayered, hybrid, and other types of particles [5]; and (4) a good knowledge of the micellar and microemulsion struc ture. Unfortunately, there only few studies directed to the preparation of nanoparticles of water soluble salts by the microemulsion method. For example, Co(NO 3 ) 2 , CaCl 2 , Na 2 HPO 4 , and Cu(NO 3 ) 2 nanopar ticles have been prepared in a solid phase concentrate in an AOT matrix (sodium di(2 ethylhexyl)sulfosucci nate) via distilling off the solvent (heptane) and water [6,7].Meanwhile, studies of microemulsion synthesis as applied to prepare powders and liquid hydrophobic concentrates of nanoparticles of water soluble energy intensive salts seem to be very promising for both sci ence and application. For example, reverse emulsions of supersaturated ammonium nitrate solutions [8,9] in diesel fuel have almost substituted for TNT con taining industrial explosives [10-13].Our goal here was to study the possibility of prepar ing powders of water soluble salts in reverse micro emulsions of oxyethylated surfactant Tergitol NP 4. EXPERIMENTALReagents The micelle forming surfactant used was oxyethy lated nonylphenol with an average oxyethylation number of four, namely, Tergitol NP 4 (from Dow Chemical). A micellar solution contained 0.25 mol/L Tergitol NP 4 in n decane. The organic solvents used were pure grade n decane and N,N dimethylforma mide (DMF) and high purity grade heptane and ace tone. The initial reagents used were concentrated nitric acid (high purity grade, 16.2 mol/L), concentrated aqueous ammonia (high purity grade, 10.8 mol/L), KOH, and NaBH 4 (both of pure grade), NH 4 NO 3 (pure for analysis grade), and KNO 3 (chemically pure grade). Structural Study of Microemulsions and PowdersThe limiting solubilization capacity V s /V o (the vol ume ratio of an aqueous solubilizate solution to a sol ubilizate containing micellar solution) of a micro emulsion system with respect to aqueous solutions of reagents and salts was determined by serial injections of small volumes of the aqueous phase. The cloud point was detected visually and spectrophotometri cally by an abrupt increase in the absorbance of the solution. Measurements were carried out on a Shi madzu 1700 spectrophotometer using quartz cells (l = 1 cm); the reference solution was a "dry" micellar solution.Microemulsions with initial reagents were structur ally studied by photon correlation spectroscopy and Abstract-The feasibility of preparing energy saturated salts (NH 4 NO 3 , KNO 3 , and NaBH 4 ) in powders with various particle sizes in microemulsion systems based on oxyethylated surfactant Tergitol NP 4 has been demonstrated. Powders were isolated by destroying microemulsio...

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Section: Results and Discussion Preparation And Characterization Of Psupporting

confidence: 81%

Section: Results and Discussion Preparation And Characterization Of Pmentioning

confidence: 99%

Microemulstion synthesis of powders of water-soluble energy-saturated salts

Булавченко

Демидова

Podlipskaya

et al. 2012

Russ. J. Inorg. Chem.

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“…It was of interest to compare the spectra of the dye and both ion associates in aqueous solutions and in micelles with 10% Triton N-42 in decane upon the quantitative extraction of cetyltrimethylammonium bromide (1 M NaCl, t = 1 h, V w : V o = 5 : 1) [6]. The pH of the aqueous phase was adjusted using citrate buffer solutions [4].…”

Section: Spectral Characteristics Of the Micellar Solutionsmentioning

confidence: 99%

“…To do this, it was proposed to decompose the micellar solution by adding chloroform to 25 vol % in the diluted solution [6] and then stir the mixture. The optimum phase contact time was 10 min.…”

Section: Demidova Bulavchenkomentioning

confidence: 99%

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Extraction by reversed micelles of triton N-42 for the spectrophotometric determination of cetyltrimethylammonium bromide

Демидова

Булавченко

2005

J Anal Chem

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Cationic surfactants are widely used in the production of cosmetics, in textile industry, in chemical analysis, and as flotation agents in wastewater treatment. Quaternary ammonium salts, in particular, cetyltrimethylammonium and cetylpyridinium halides are most commonly used. The determination of their low concentrations in natural, potable, and wastewater is an important problem because of the high environmental stability of these compounds [1].Modified potentiometric sensors were successfully used to individually determine 10 -6 to 10 -3 M alkylpyridinium chlorides [2]. Total cationic surfactants can also be determined by the extraction-fluorimetry using Eosin (analytical range is 10 -8 to 10 -6 M) [3] and extraction-spectrophotometry using Bromophenol Blue (analytical range is 10 -6 to 10 -5 M) [4]. These methods are based on the solvent extraction of the cationic surfactant-reagent ion associates with chloroform. The absolute preconcentration factor of two to five is insufficient for spectrophotometric determination of low concentrations of cationic surfactants.The use of micelle formation is promising for improving the analytical performance of the spectrophotometric procedures [5]. Earlier [6], we demonstrated the efficient extraction of cetyltrimethylammonium bromide by reversed micelles of Triton N-42 in decane (distribution coefficient is higher than 2 × 10 3 ). This made a 100-fold absolute preconcentration possible in one extraction stage. In this paper, the proposed version of micellar extraction is used for enhancing the possibilities of the spectrophotometric determination of cationic surfactants as ion associates. EXPERIMENTAL Reagents and solutions.Distilled water was used throughout. The concentration of the main substance in cetyltrimethylammonium bromide (Merck) was determined by potentiometric titration with 0.01 M sodium tetraphenylborate (Fluka) by the procedure described in [7]. The stock 2.50 × 10 -3 M solution of cetyltrimethylammonium bromide was prepared by dissolving a weighed portion of the reagent in water while heating in a water bath at 70 ° C; the intermediate and working solutions were prepared by diluting the stock solution before extraction. The solution of Bromophenol Blue (1.0 × 10 -3 M) was prepared the day the experiments were performed by dissolving 16.8 mg of the dye in 2 mL of 0.1 M NaOH followed by dilution with water to 25 mL. The stock ammonium sulfate buffer solution with pH 9.3 [1 M NH 3 + 1 M (NH 4 ) 2 SO 4 ] was prepared from chemically pure reagents. Citrate buffer solutions (pH 2.0 and 5.5) were prepared from chemically pure citric acid, NaOH, and 0.1 M HCl from the volumetric standard. The supporting electrolyte was 2 M NaCl of high-purity grade 6-4. The extractant was a 10 wt % solution of polyoxyethylene glycol nonylphenyl ether (four units, Sigma) in n -decane of reagent grade. Micellar solutions were decomposed with pharmaceutical chloroform that was washed with water and 0.1 M NaCl in an ammonium sulfate buffer solution (1 : 100) for 3 min, centrifuged, a...

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Fluorescence saturation of dye molecules in water pools of reversed micelles

Потапов

Saletsky²

2005

Laser Phys. Lett.

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Rhodamine 6G has been used as a fluorescence probe in AOT reversed micelles systems with the different amounts of solubilized water (hydratation power ω). The saturation of fluorescence and the lifetime of dye molecules were measured. The absorption cross section values were calculated from the saturation curves. We showed the differences in values of the absorption cross section, lifetime and velocity of fluorescence saturation in micellar phase with different ω and in comparison to bulk phase. Additionally, the structure of hydrated reversed micelles has been studied by the method of correlation spectroscopy. The influence of ω on size and shape of micelles was detected.

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Cited by 8 publications

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Microemulstion synthesis of powders of water-soluble energy-saturated salts

Microemulstion synthesis of powders of water-soluble energy-saturated salts

Extraction by reversed micelles of triton N-42 for the spectrophotometric determination of cetyltrimethylammonium bromide

Fluorescence saturation of dye molecules in water pools of reversed micelles

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