The Experts below are selected from a list of 210 Experts worldwide ranked by ideXlab platform
H. H. Hatt - One of the best experts on this subject based on the ideXlab platform.
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Organic Syntheses - unsym.‐Dimethylhydrazine Hydrochloride
Organic Syntheses, 2003Co-Authors: H. H. HattAbstract:unsym.-Dimethylhydrazine Hydrochloride intermediate: Nitrosodimethylamine product: unsym.-Dimethylhydrazine Hydrochloride Keywords: nitrosation; reduction, NO NH2
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Organic Syntheses - sym.‐Dimethylhydrazine Dihydrochloride
Organic Syntheses, 2003Co-Authors: H. H. HattAbstract:sym.-Dimethylhydrazine dihydrochloride intermediate: dibenzoylhydrazine intermediate: dibenzoylDimethylhydrazine product: Dimethylhydrazine dihydrochloride Keywords: acylation; alkylation, N-alkylation; hydrolysis, miscellaneous; dimethyl sulfate, poison; dimethyl sulfate, ammonia antidote
O. A. Shpigun - One of the best experts on this subject based on the ideXlab platform.
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specific features of sample preparation upon chromatographic determination of 1 1 Dimethylhydrazine and n nitrosodimethylamine in peaty soils
Moscow University Chemistry Bulletin, 2015Co-Authors: A. D. Smolenkov, D S Kosyakov, N V Ulyanovskii, K G Bogolitsyn, Danil I Falev, O. A. ShpigunAbstract:The applicability of existing methods of extraction and chromatographic determination of mobile forms of 1,1-dimetylhydrazine and an important product of its oxidation transformation—N-nitrosodimethylamine—for analysis of peaty boggy soils typical for the European North of the Russian Federation is evaluated. It is shown that within a 3-day period after 1,1-dimetylhydrazine penetration into the soil, no more than 15% of its initial content may be extracted. It is revealed that the greatest amount of unsymmetrical Dimethylhydrazine is extracted from peat upon distillation with steam in the medium of 40% solution of sodium hydroxide. Conditions of sample preparation and chromatographic determination of nitrosodimethylamine in soils with high organic matter content are optimized.
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precolumn derivatization with glyoxal as a new approach to the highly sensitive hplc uv determination of unsymmetrical Dimethylhydrazine
Journal of Analytical Chemistry, 2013Co-Authors: R S Smirnov, A. D. Smolenkov, T A Bolotnik, O. A. ShpigunAbstract:A procedure has been developed for the determination of unsymmetrical Dimethylhydrazine (UDMH) based on precolumn derivatization with glyoxal and determination of the produced derivative, mono-1,1-dimethylhydrazone of glyoxal, by reversed-phase HPLC (RP-HPLC) with UV detection at 305 nm. It has been demonstrated that the reaction of UDMH with an excess of glyoxal in solution quantitatively yields one stable product within 20 min at 25°C at pH 3.5. To increase the sensitivity of UDMH determination it has been proposed to perform solid-phase extraction preconcentration of the derivative from a 25-mL sample portion on cartridges containing Strata SDB-L polymer adsorbent. The analytical range of UDMH determination in water is 0.5–10000 μg/L or 0.01–20 μg/L using preconcentration. The relative standard deviations of UDMH determination (n = 3) do not exceed 0.12 and 0.25 without and with preconcentration, respectively. The accuracy of UDMH determination is confirmed by the analysis of spiked samples and by RP-HPLC determination with preliminary derivatization with 4-nitrobenzaldehyde as independent method.
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use of ion and ion pair chromatography with mass spectrometric detection to determine unsymmetrical Dimethylhydrazine and its transformation products
Moscow University Chemistry Bulletin, 2012Co-Authors: A. D. Smolenkov, I. A. Rodin, R S Smirnov, O G Tataurova, O. A. ShpigunAbstract:The conditions of the simultaneous determination of unsymmetrical Dimethylhydrazine (UDMH) and products of its transformation in aqueous solutions with ion and ion-pair chromatography and mass-spectrometric detection in the electrospray ionization mode have been selected. It has been shown that up to seven components may be determined within the limits of detection at the μg/L level. The application of the developed methods to the analysis of solutions with an initial UDMH concentration of 500 mg/L that had undergone spontaneous oxidation by atmospheric oxygen has been demonstrated. The accumulation of formic acid dimethylhydrazide, 1-methyl-1,2,4-triazole and dimethylamine has been found.
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effect of sample preparation conditions on the determination of the total concentrations of unsymmetrical Dimethylhydrazine in soils
Journal of Analytical Chemistry, 2012Co-Authors: A. D. Smolenkov, I. A. Rodin, R S Smirnov, O G Tataurova, O. A. ShpigunAbstract:It is shown that, for a correct determination of the total concentration of unsymmetrical Dimethylhydrazine (UDMH) in soil, it is necessary to consider the simultaneous presence of active products of its transformation, capable of hydrolysis to the parent compound, such as formic acid 1,1-dimethylhydrazide (FADMH). A comparative study is performed of the methods known in the literature for sample preparation to select conditions for the quantitative extraction of UDMH bonded by various mechanisms to organic and mineral fractions of soil, as well as FADMH as one of the most common active transformation products. It is found that the distillation with a 40% NaOH solution with an addition of Na2S enables the quantitative recovery of UDMH and FADMH from soils of all types and the determination of the maximum concentration of UDMH in the analysis of real samples of contaminated soils, which allows us to recommend this option to determine the total concentration of UDMH.
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determination of the products of the oxidative transformation of unsymmetrical Dimethylhydrazine in soils by liquid chromatography mass spectrometry
Journal of Analytical Chemistry, 2010Co-Authors: I. A. Rodin, A. D. Smolenkov, I A Ananeva, O. A. ShpigunAbstract:Procedures are developed on the basis of liquid chromatography/mass spectrometry for determining the transformation products of unsymmetrical Dimethylhydrazine in soils: formic acid dimethylhydrazide (1-formyl-2,2-Dimethylhydrazine, analytical range 0.01–20 mg/kg), 1-methyl-1,2,4-triazole (analytical range 0.05–100 mg/kg), 1,1-dimethylguanidine (analytical range 0.05–100 mg/kg), and dimethylamine (analytical range 0.25–250 mg/kg). The measurements were performed in the mode of chemical ionization under atmospheric pressure followed by the registration of positive ions corresponding to the protonated forms of the components to be determined. A version of ion chromatography was elaborated for separation. For sample pretreatment, the use of extraction with methanol (for 1-formyl-2,2-Dimethylhydrazine) and ultrasonic extraction with a weakly alkaline buffer solution (for other substances) was proposed.
Hong Yuan - One of the best experts on this subject based on the ideXlab platform.
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Bimodal visualization of colorectal uptake of nanoparticles in Dimethylhydrazine-treated mice.
World journal of gastroenterology, 2011Co-Authors: Weiliang Zheng, Shi-zheng Zhang, Ji-hong Sun, Hong YuanAbstract:Bimodal visualization of colorectal uptake of nanoparticles in Dimethylhydrazine-treated mice
M.h.j.m. De Croon - One of the best experts on this subject based on the ideXlab platform.
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Oxidation of organic compounds in a microstructured catalytic reactor
Chemical Engineering Journal, 2008Co-Authors: I.z. Ismagilov, E. M. Michurin, O. B. Sukhova, L.t. Tsykoza, E.v. Matus, Mikhail A. Kerzhentsev, Zinfer R. Ismagilov, Andrey N Zagoruiko, Evgeny V. Rebrov, M.h.j.m. De CroonAbstract:A microstructured catalytic reactor for the oxidation of organic compounds has been fabricated from aluminum alloy AlMgSiCu1 (6082 series, Al51st). The catalyst section was assembled of 63 microstructured plates with catalytic coating. In each plate of 416m thickness, 45 semicylindrical microchannels of 208m in radius with a distance in between of 150m were electrodischarge machined. A porous alumina layer of 29 ± 1m thickness was produced on the plates by anodic oxidation. The resulting coatings were impregnated with an aqueous solution of copper dichromate followed by drying and calcination at 450 ◦ C to produce active catalysts. Kinetics of deep oxidation of organic compounds n-butane, ethanol, and isopropanol was studied in the reactor at 150–360 ◦ C and of 1,1-Dimethylhydrazine (unsymmetrical Dimethylhydrazine, UDMH) at 200–375 ◦ C. Intermediate reaction products in the reactions of alcohols and UDMH oxidation were identified. For UDMH, these are methane, dimethylamine, formaldehyde 1,1-dimethylhydrazone, and 1,2-dimethyldiazene. Nitrogen atoms from the UDMH and N-containing intermediates were shown to convert mainly to N2. Kinetic parameters of the reactions of n-butane and alcohols (rate constants and apparent activation energies) were calculated using kinetic modeling based on a modified method of quickest descent. © 2007 Elsevier B.V. All rights reserved.
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Oxidation of organic compounds in a microstmctured catalytic reactor
Chemical Engineering Journal, 2008Co-Authors: I.z. Ismagilov, E. M. Michurin, O. B. Sukhova, L.t. Tsykoza, E.v. Matus, Mikhail A. Kerzhentsev, Zinfer R. Ismagilov, Andrey N Zagoruiko, Evgeny V. Rebrov, M.h.j.m. De CroonAbstract:A microstructured catalytic reactor for the oxidation of organic compounds has been fabricated from aluminum alloy AlMgSiCul (6082 series, A151st). The catalyst section was assembled of 63 microstructured plates with catalytic coating. In each plate of 416 μm thickness, 45 semicylindrical microchannels of 208 μm in radius with a distance in between of 150 μm were electrodischarge machined. A porous alumina layer of 29 ± 1 μm thickness was produced on the plates by anodic oxidation. The resulting coatings were impregnated with an aqueous solution of copper dichromate followed by drying and calcination at 450 °C to produce active catalysts. Kinetics of deep oxidation of organic compounds n-butane, ethanol, and isopropanol was studied in the reactor at 150-360°C and of 1,1-Dimethylhydrazine (unsymmetrical Dimethylhydrazine, UDMH) at 200-375 °C. Intermediate reaction products in the reactions of alcohols and UDMH oxidation were identified. For UDMH, these are methane, dimethylamine, formaldehyde 1,1-dimethylhydrazone, and 1,2-dimethyldiazene. Nitrogen atoms from the UDMH and N-containing intermediates were shown to convert mainly to N 2 . Kinetic parameters of the reactions of n-butane and alcohols (rate constants and apparent activation energies) were calculated using kinetic modeling based on a modified method of quickest descent.
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Micro structured reactors for synthesis/decomposition of hazardous chemicals. Challenging prospects for micro structured reaction architectures (4)
2004Co-Authors: Evgeny V. Rebrov, M.h.j.m. De Croon, J.c. SchoutenAbstract:A review. This paper completes a series of four publications dealing with the different aspects of the applications of micro reactor technol. This article focuses on the application of micro structured reactors in the processes for synthesis/decompn. of hazardous chems., such as unsym. Dimethylhydrazine (UDMH), a component of high-energy propellant for liq. fuel rockets. Several examples including highly exothermic reactions with a highly toxic component of high-energy propellant, unsym. Dimethylhydrazine, are reviewed. [on SciFinder (R)]
Dmitry S. Kosyakov - One of the best experts on this subject based on the ideXlab platform.
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Modification of sulfate lignin with sodium periodate to obtain sorbent of 1,1-Dimethylhydrazine
Russian Journal of Applied Chemistry, 2017Co-Authors: A. Yu. Kozhevnikov, S A Pokryshkin, I. I. Pikovskoi, S. L. Ul’yanovskaya, Marina P. Semushina, A. V. Ladesov, Dmitry S. KosyakovAbstract:Application of the oxidative modification of sulfate kraft lignin with sodium periodate under mild conditions is suggested in order to obtain a sorbent for detoxication of spillage places of rocket fuels based on 1,1-Dimethylhydrazine and to purify wastewaters containing this compound. It was found that processing with the periodate at a temperature of 55°C for 20 h results in a more than twofold increase in the content of carbonyl and quinone groups in a lignin preparation and a rise in its polydispersity due to the appearance of a macromolecular condensed fraction and a threefold increase in the sorption capacity for 1,1-Dimethylhydrazine. The sorbent can bind 6.7% of 1,1-Dimethylhydrazine and substantially surpasses in this parameter other lignin-based sorbents. It was shown that the firm chemical binding of hydrazines hinders desorption of the highly toxic rocket propellant and products of its oxidative transformation from the surface of lignin both into solution and into the vapor phase, thereby providing safe handling of the spent sorbent.
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Characterisation of oxidation products of 1,1-Dimethylhydrazine by high-resolution orbitrap mass spectrometry.
Chemosphere, 2017Co-Authors: Nikolay V. Ul'yanovskii, Dmitry S. Kosyakov, I. I. Pikovskoi, Yu. G. KhabarovAbstract:Abstract 1,1-Dimethylhydrazine is used as a fuel for carrier rockets in the majority of countries implementing space exploration programs. Being highly reactive, 1,1-Dimethylhydrazine easily undergoes oxidative transformation with the formation of a number of toxic, mutagenic, and teratogenic compounds. The use of high-resolution mass spectrometry for the study of the reaction of 1,1-Dimethylhydrazine oxidation with hydrogen peroxide in aqueous solution allowed us to find hundreds of nitrogen-containing products of the CHN and CHNO classes, formed via radical processes. The vast majority of the compounds have not been previously considered as possible products of the transformation of rocket fuel. We have shown that the oxidation of 1,1-Dimethylhydrazine proceeds in two stages, with the formation of a great number of complex unstable intermediates that contain up to ten nitrogen atoms. These intermediates are subsequently converted into final reaction products with a concomitant decrease in the average molecular weight. The intermediates and final products of the oxidative transformation of 1,1-Dimethylhydrazine were characterised on the basis of their elemental composition using van Krevelen diagrams and possible compounds corresponding to the most intense peaks in the mass spectra were proposed. The data obtained are indicative of the presence of the following classes of heterocyclic nitrogen-containing compounds among the oxidation products: imines, piperidines, pyrrolidines, dihydropyrazoles, dihydroimidazoles, triazoles, aminotriazines, and tetrazines. The results obtained open up possibilities for the targeted search and identification of new toxic products of the degradation of rocket fuel and, as a result, a more adequate assessment of the ecological consequences of space-rocket activity.
