- Formation of N-nitrosodimethylamine (NDMA) from dimethylamine during chlorination
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Chlorine disinfection of secondary wastewater effluent and drinking water can result in the production of the potent carcinogen N-nitrosodimethylamine (NDMA) at concentrations of approximately 100 and 10 parts per trillion (ng/L), respectively. Laboratory experiments with potential NDMA precursors indicate that NDMA formation can form during the chlorination of dimethylamine and other secondary amines. The formation of NDMA during chlorination may involve the slow formation of 1,1-dimethylhydrazine by the reaction of monochloramine and dimethylamine followed by its rapid oxidation to NDMA and other products including dimethylcyanamide and dimethylformamide. Other pathways also lead to NDMA formation during chlorination such as the reaction of sodium hypochlorite with dimethylamine. However, the rate of NDMA formation is approximately an order of magnitude slower than that observed when monochloramine reacts with dimethylamine. The reaction exhibits a strong pH dependence due to competing reactions. It may be possible to reduce NDMA formation during chlorination by removing ammonia prior to chlorination, by breakpoint chlorination, or by avoidance of the use of monochloramine for drinking water disinfection.
- Mitch, William A.,Sedlak, David L.
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- Oxidation of citalopram with sodium hypochlorite and chlorine dioxide: Influencing factors and NDMA formation kinetics
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The highly prescribed antidepressant, citalopram, as one of newly emerging pollutants, has been frequently detected in the aquatic environment. Citalopram oxidation was examined during sodium hypochlorite (NaOCl) and chlorine dioxide (ClO2) chlorination processes since conventional wastewater treatment plants cannot remove citalopram effectively. Citalopram has been demonstrated to form N-nitrosodimethylamine (NDMA) during chlorination in our previous study. Further investigation on NDMA formation kinetics was conducted in the present study. Influences of operational variables (disinfectant dose, pH value) and water matrix on citalopram degradation, as well as NDMA generation, were evaluated. The results indicated high reactivity of citalopram with NaOCl and ClO2. NDMA formation included two stages during CIT oxidation, which were linear related with reaction time. NaOCl was more beneficial to remove CIT, but it caused more NDMA formation. Increasing disinfectant dosage promoted citalopram removal and NDMA formation. However, no consistent correlation was found between citalopram removal and pH. Contrary to the situation of citalopram removal, NDMA generation was enhanced when citalopram was present in actual water matrices, especially in secondary effluent. DMA, as an intermediate of citalopram chlorination, contributed to NDMA formation, but not the only way.
- Lv, Juan,Wang, Yan,Li, Na
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- Characterization and Fate of N-Nitrosodimethylamine Precursors in Municipal Wastewater Treatment Plants
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The potent carcinogen, N-nitrosodimethylamine (NOMA), is produced during disinfection of municipal wastewater effluent from the reaction of monochloramine and organic nitrogen-containing precursors. To delineate the sources and fate of NDMA precursors during municipal wastewater treatment, NDMA formation was measured after extended chloramination of both model precursors and samples from conventional and advanced wastewater treatment plants. Of the model precursors, only dimethylamine, tertiary amines with dimethylamine functional groups, and dimethylamides formed significant NDMA concentrations upon chloramination. In samples from municipal wastewater treatment plants, dissolved NDMA precursors always were present in primary and secondary effluents. Biological treatment effectively removed the known NDMA precursor dimethylamine, lowering its concentration to levels that could not produce significant quantities of NDMA upon chlorine disinfection. However, biological treatment was less effective at removing other dissolved NDMA precursors, even after extended biological treatment. Significant concentrations of particle-associated NDMA precursors only were detected in secondary effluent at treatment plants that recycled water from sludge thickening operations in which dimethylamine-based synthetic polymers were used. Effective strategies for the prevention of NDMA formation during wastewater chlorination include ammonia removal by nitrification to preclude chloramine formation during chlorine disinfection, elimination of dimethylamine-based polymers, and use of filtration and reverse osmosis to remove particle-associated precursors and dissolved precursors, respectively.
- Mitch, William A.,Sedlak, David L.
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- Formation of N-nitrosodimethylamine (NDMA) from reaction of monochloramine: A new disinfection by-product
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Studies have been conducted specifically to investigate the hypothesis that N-nitrosodimethylamine (NDMA) can be produced by reactions involving monochloramine. Experiments were conducted using dimethylamine (DMA) as a model precursor. NDMA was formed from the reaction between DMA and monochloramine indicating that it should be considered a potential disinfection by-product. The formation of NDMA increased with increased monochloramine concentration and showed maximum in yield when DMA was varied at fixed monochloramine concentrations. The mass spectra of the NDMA formed from DMA and 15N isotope labeled monochloramine (15NH2Cl) showed that the source of one of the nitrogen atoms in the nitroso group in NDMA was from monochloramine. Addition of 0.05 and 0.5mM of preformed monochloramine to a secondarily treated wastewater at pH 7.2 also resulted in the formation of 3.6 and 111ng/L of NDMA, respectively, showing that this is indeed an environmentally relevant NDMA formation pathway. The proposed NDMA formation mechanism consists of (i) the formation of 1,1-dimethylhydrazine (UDMH) intermediate from the reaction of DMA with monochloramine followed by, (ii) the oxidation of UDMH by monochloramine to NDMA, and (iii) the reversible chlorine transfer reaction between monochloramine and DMA which is parallel to (i). We conclude that reactions involving monochloramine in addition to classical nitrosation reactions are potentially important pathways for NDMA formation. Copyright
- Choi, Junghoon,Valentine, Richard L.
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- Infrared Multiphoton Decomposition of Dimethylnitramine
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The infrared multiphoton dissociation of dimethylnitramine in the gas phase by a pulsed CO2 laser has been studied in order to elucidate its photochemical decomposition mechanism under collisionless conditions and provide a qualitative understanding of the consequent chemical mechanism that leads to the final products.The experimentally determined steady-state rate coefficient for the unimolecular decomposition of dimethylnitramine was found to be k(st) = 105.5+/-0.1 (I/MW cm-2)s-1 for laser intensities 2-10 MW cm-2.Scavenging experiments with Cl2, NOCl, NO,NO2, and (CD3)2NNO2 molecules have shown that the decomposition dynamics proceeds through scission of the N-NO2 bond, with no evidence of the HONO elimination or the isomerization to nitro-nitrite channel.Dimethylnitrosamine was the major final product which was mainly produced through oxidation of dimethylamino radical by dimethylnitramine.
- Lazarou, Yannis G.,Papagiannakopoulos, Panos
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- Kinetic Studies on the Formation of N-Nitroso Compounds XI. Nitrosation of Dimethylamine with Nitrite Esters in Aqueous Basic Media
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A kinetic study of the mechanism of the nitrosation of dimethylamine (DMA) by propyl nitrite (PrONO) in basic media to yield N-nitrosodimethylamine (NDMA) has found the rate equation to be ν=d/dt=k2/(1++>/K1) where and are total concentrations.At 298.2 K and I=0.25 M, k2=(6.59+/-0.13)*1E-2 M-1s-1 and K1=(1.16+/-0.07)*1E-11 M.The observed influence of ionic strength, the kinetic results obtained in water/tetrahydrofuran mixtures and in heavy water (kH/kD=2.09), and the value of ΔS(excit.)(-158 JK-1mol-1) suggest that the nitrosating agent PrONO attacks the free amine to create a tetracentric transition state and that this is the rate controlling step of the reaction.Experiments carried out with other nitrite esters have shown there to be a correlation satisfying Taft's equation between their structure and their reactivity with DMA (ρ*=3.89), which allows the rate constant for nitrous acid to be calculated. - Keywords: Dimethylamine; Kinetics of nitrosation; Nitrite esters; N-Nitrosodimethylamine
- Casado, Julio,Castro, Albino,Lorenzo, Francisco M.,Meijide, Francisco
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- Degradation of gaseous unsymmetrical dimethylhydrazine by vacuum ultraviolet coupled with MnO2
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In this study, α-, β-, and δ-MnO2 were prepared by a uniform hydrothermal method and then coupled with vacuum ultraviolet (VUV) for the degradation of gaseous unsymmetrical dimethylhydrazine (UDMH). The performance in the removal of UDMH, by-product distribution and mechanism were systematically investigated. The catalysts were characterized by X-ray diffraction (XRD), N2 adsorption/desorption, Field Emission Scanning Electron Microscopy (FE-SEM), Raman, thermogravimetry (TG), Fourier-transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) to investigate the factors affecting the catalytic activity. The results showed that O2 and H2O were essential for the removal of UDMH. Photooxidation and ozone catalytic oxidation contribute to the removal and mineralization of UDMH. The integrated process considerably improved the removal and mineralization of UDMH by ozone catalytic oxidation. More reactive oxygen species were generated in the integrated process. The catalytic activity of the prepared catalysts follows the order: δ-MnO2 > α-MnO2 > β-MnO2. δ-MnO2 displayed the highest removal rate of 100% and a CO2 concentration of 42 ppmv. The good performance of δ-MnO2 was mainly attributed to the large number of surface oxygen vacancies.
- Huang, Yuanzheng,Jia, Ying,Shen, Keke,Hou, Ruomeng,Zhang, Yongyong,Hou, Li'an
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supporting information
p. 1194 - 1202
(2021/02/06)
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- Adsorption and photocatalytic degradation of gas-phase UDMH under simulated sunlight by AgBr/TiO2/rGA
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The degradation of UDMH has long been a concern for its harmful effects on humans and the environment. The current research on gas-phase UDMH treatment is limited and mainly focuses on ultraviolet light and high temperature environments, however the highly toxic substance NDMA is easily produced. In order to investigate the possibility of UDMH degradation in sunlight, AgBr/TiO2/rGA composites were prepared with the addition of different amounts of silver bromide. The highest UDMH conversion of AgBr/TiO2/rGA in humid air is 51%, much higher than the control group value of 24%, which can be ascribed to the synergy of adsorption and photocatalysis. The graphene and silver in AgBr/TiO2/rGA not only enhance the adsorption of light and UDMH, but also inhibit charge recombination and enhance electron-hole separation. More importantly, the temperature of the AgBr/TiO2/rGA composite was raised by the photothermal effect of graphene with promoted UDMH degradation efficiency. Furthermore, it is noted that NDMA was not detected in the optimal conditions.
- Ruomeng, Hou,Ying, Jia,Xiaomeng, Lv,Yuanzheng, Huang,Keke, Shen
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p. 12583 - 12594
(2021/04/14)
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- TiO2-reduced graphene oxide for the removal of gas-phase unsymmetrical dimethylhydrazine
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Unsymmetrical dimethylhydrazine (UDMH) contaminated waste gas and related intermediates pose a great threat to human health. TiO2-reduced graphene oxide aerogel (rGA) samples with different graphene content levels were synthetized and characterized for the degradation of UDMH. The effects of GO content, humidity, and temperature were investigated under UV and VUV light, with highest UDMH conversion values of 68% and 95%, respectively. Compared with pure TiO2, the enhanced degradation activity of TiO2-rGA under UV light can be attributed to a synergetic effect between absorption and photocatalysis, while the high UDMH conversion under VUV light relies on photolysis and ozonation. The high oxygen-containing group content, rather than a high SSA, and electron trapping by graphene are key factors determining the outstanding performance of TiO2-rGA with 80 mg of GO. The prepared TiO2-graphene aerogels are promising for the degradation of gas-phase UDMH. This journal is
- Ruomeng, Hou,Ying, Jia,Yuanzheng, Huang,Keke, Shen,Huixin, Zhu
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p. 394 - 402
(2021/01/11)
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- Preparation method of PI3K inhibitor
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The invention provides a preparation method of a PI3K inhibitor. The PI3K inhibitor is (S)-2-[1-(9H-purine-6-ylamino) ethyl]-3-(dimethylamino)-5-fluoroquinazoline-4 (3H)-ketone, and the structural formula of the PI3K inhibitor is shown in the specification. The method comprises three steps of reactions. The method has the advantages of simple reaction steps, mild reaction conditions, indiscriminate application of the solvent, economy and environmental protection. The PI3K inhibitor is subjected to optical purification and salifying crystallization refining through organic acid resolution and has simplicity in operation, improved yield, low cost and more stable batch-to-batch quality in comparison with present silica gel column chromatography and preparation separation and is suitable for industrial production.
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Paragraph 0062-0064
(2020/08/02)
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- Identification of unexpected unlabeled N,N-dimethylamide formation in the synthesis of deuterated fragment of ribociclib by a HATU-mediated coupling reaction
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Starting from N,N-dimethylamine and D2O, deuterated fragment of ribociclib was synthesized for use as a mass spectroscopy internal standard. Furthermore, systematic studies on D0 (unlabeled material) formation during the amidation reaction were performed, leading to the identification of a coupling reagent, HATU (O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate), as main cause. Finally, an alternative route was designed using EDCI/HOBT as coupling reagents to produce the desired deuterated compound without D0 residue.
- Gai, Kuo,Liu, Baomin,Zhang, Yinsheng
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- Thermal behavior of ammonium dinitramide and amine nitrate mixtures
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This paper focuses on the thermal behavior of mixtures of ammonium dinitramide (ADN) and amine nitrates. Because some mixtures of ADN and amine nitrate exhibit low melting points and high-energy content, they represent potential liquid propellants for spacecraft. This study focused on the melting behavior and thermal-decomposition mechanisms in the condensed phase of ADN/amine nitrate mixtures during heating. We measured the melting point and exothermal behavior during constant-rate heating using differential scanning calorimetry and performed thermogravimetry–differential thermal analysis–mass spectrometry (TG–DTA–MS) to analyze the thermal behavior and evolved gases of ADN/amine nitrate mixtures during simultaneous heating to investigate their reaction mechanisms. Results showed that the melting point of ADN was significantly lowered upon the addition of amine nitrate with relatively low molecular volume and low melting point. TG–DTA–MS results showed that the onset temperature of the thermal decomposition of ADN/amine nitrates was similar to that of pure ADN. Furthermore, during thermal decomposition in the condensed phase, ADN produced highly acidic products that promoted exothermic reactions, and we observed the nitration and nitrosation of amines from the dissociation of amine nitrates.
- Matsunaga, Hiroki,Katoh, Katsumi,Habu, Hiroto,Noda, Masaru,Miyake, Atsumi
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p. 2677 - 2685
(2018/11/23)
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- Metal-Free Cycloetherification by in Situ Generated P-Stereogenic α-Diazanium Intermediates: A Convergent Synthesis of Enantiomerically Pure Dihydrobenzooxaphospholes
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A metal-free tandem reaction, initiated by the generation of a diazonium cation and followed by cycloetherification, was developed. Acid-promoted de-tert-butylation of N-nitroso N-tert-butylamine was used to generate a diazonium cation in situ, demonstrating a new application of nitroso chemistry. This reaction was employed in the synthesis of substituted benzofuran-3(2H)-ones and dihydrobenzo[d][1,3]oxaphosphole 3-oxides.
- Li, Shi-Guang,Han, Zhengxu S.,Viereck, Peter,Lee, Heewon,Kurouski, Dmitry,Senanayake, Chris H.,Tsantrizos, Youla S.
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supporting information
p. 894 - 897
(2017/02/26)
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- Kinetic and Theoretical Study of the Nitrate (NO3) Radical Gas Phase Reactions with N-Nitrosodimethylamine and N-Nitrosodiethylamine
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The reaction rates of (CH3)2NNO and (CH3CH2)2NNO with NO3 radicals were determined relative to formaldehyde (CH2O) and ethene (CH2CH2) at 298 ± 2 K and 1013 ± 10 hPa in purified air by long path FTIR spectroscopy. The reactions are too slow to be of importance at atmospheric conditions: k NO3+(CH3)2NNO = (1.47 ± 0.23) × 10-16 and k NO3+(CH3CH2)2NNO = (5.1 ± 0.4) × 10-16 cm3 molecule-1 s-1 (1σ error limits). Theoretical calculations, based on CCSD(T?)-F12a/aug-cc-pVTZ//M06-2X/aug-cc-pVTZ results, predict the corresponding imines as the sole primary products in nitrosamine reactions with NO3 and OH radicals.
- Maguta, Mihayo Musabila,Stenstr?m, Yngve,Nielsen, Claus J.
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p. 6970 - 6977
(2016/10/12)
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- Catalyst for the degradation of 1,1-dimethylhydrazine and its by-product N-nitrosodimethylamine in propellant wastewater
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A three-component metal catalyst was prepared and used in the process of catalytic wet peroxide oxidation (CWPO) for the degradation of unsymmetrical dimethylhydrazine (UDMH) in propellant wastewater with H2O2. It was structurally characterized using scanning electron spectroscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDX), and its catalytic activity was evaluated using indexes such as the efficiency of UDMH degradation and chemical oxygen demand (COD) removal and the concentrations of ammonia (NH3-N), formaldehyde (HCHO), total nitrogen (TN), total organic carbon (TOC) and N-nitrosodimethylamine (NDMA). Besides, the reaction system was monitored using UV-Vis full wavelength scanning spectroscopy and liquid chromatography-mass spectroscopy (LC-MS). As a result, it was observed that the degradation mechanism involved OH attacking the amino group and homocoupling in UDMH with the simultaneous transformation of the active component CuII/I. Based on investigation of the reaction factors (H2O2 dosage, temperature, catalyst dosage, pH and initial concentration of UDMH) focusing on the removal of NDMA, the optimal conditions for CWPO with a three-component metal catalyst were determined. The high treatable concentration of UDMH (500 mg L-1), rapid rate and good reusability with a high efficiency of UDMH degradation and COD removal (99.9% in 10 min and 94.6% in 30 min, respectively) and the low concentration of NDMA are merits of the present catalyst.
- Liang, Meiling,Li, Weijie,Qi, Qi,Zeng, Pingchuan,Zhou, Yucheng,Zheng, Yingping,Wu, Min,Ni, Henmei
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p. 5677 - 5687
(2016/02/05)
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- Chromatographic component of identification of the transformation products of 1,1-dimethylhydrazine in the presence of sulfur
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The gas-chromatographic retention indices of the products of 1,1-dimethylhydrazine transformations in the presence of sulfur allows one to confirm and, in ceratin cases, make more exact the results of their gas chromatography-mass spectrometry identificat
- Zenkevich,Ul'Yanov,Golub,Buryak
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p. 1106 - 1114
(2014/08/05)
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- Ionic liquid 1-(4-nitritobutyl)-3-methylimidazolium chloride as a new reagent for the efficient N-nitrosation of secondary amines under mild conditions
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1-(4-Nitritobutyl)-3-methylimidazolium chloride has been developed as a new reagent for efficient nitrosation of secondary amines at 0 °C to room temperature. A variety of N-nitrosamines were prepared in excellent yields by use of this task-specific ionic liquid under mild and heterogeneous conditions.
- Valizadeh, Hassan,Gholipour, Hamid,Shomali, Ashkan
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experimental part
p. 467 - 470
(2012/06/15)
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- 1-butyl-3-methylimidazolium nitrite as a reagent for the efficient n-nitrosation of secondary amines
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1-Butyl-3-methylimidazolium nitrite, [bmim]NO2 was used as a new effective reagent for the preparation of N-nitrosamines from the corresponding secondary amines at 0 °C to room temperature, under mild conditions in good to excellent yields.
- Valizadeh,Gholipour
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experimental part
p. 857 - 861
(2012/06/18)
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- Bismuth chloride-sodium nitrite: A novel reagent for chemoselective N-nitrosation
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Bismuth(III) chloride-sodium nitrite was used as a mild and efficient reagent for N-nitrosation of various tetrazoles, secondary amines, and amides under ambient conditions. Nitrosation took place chemoselectively at the nitrogen atom, giving corresponding N-nitroso derivatives in good to excellent yield. Copyright Taylor & Francis Group, LLC.
- Chaskar, Atul C.,Langi, Bhushan P.,Deorukhkar, Amol,Deokar, Hrushikesh
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experimental part
p. 604 - 612
(2009/07/04)
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- Efficient procedure for chemoselective N-nitrosation of secondary amines with trichloromelamine-NaNO2
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A combination of trichloromelamine and sodium nitrite in the presence of wet silica gel was used as an effective nitrosating agent for the transformation of secondary amines into the corresponding N-nitroso derivatives under mild and heterogeneous conditions in good to excellent yields.
- Bamoniri,Zolfigol,Mirjalili,Fallah
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p. 1393 - 1396
(2008/03/27)
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- Molybdate sulfuric acid/NaNO2: A novel heterogeneous system for the N-nitrosation of secondary amines under mild conditions
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Wet molybdate sulfuric acid (=dioxo[bis(sulfato-κO)]molybdenum; MSA), a new solid acid, can be used in combination with sodium nitrite (NaNO 2) to transform a variety of secondary amines to the corresponding N-nitroso compounds under mild, heterogeneous conditions (Table). The process has several advantages: the reagents are inexpensive and non-hazardous, the reaction is clean, fast, and high-yielding, and MSA can be readily removed by filtration and re-used (after treatment with HCl) without loss of activity. Further, only N-nitrosation was observed, but no C- or O-nitrosation.
- Montazerozohori, Morteza,Karami, Bahador
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p. 2922 - 2926
(2007/10/03)
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- Alumina-methanesulfonic acid (AMA)/NaNO2 as an efficient procedure for the chemoselectivite N-nitrosation of secondary amines
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A combination of alumina/methanesulfonic acid (AMA) and sodium nitrite was used as an effective nitrosating agent for the nitrosation of secondary amines under mild and heterogeneous conditions in good to excellent yields. Copyright Taylor & Francis Group, LLC.
- Niknam, Khodabakhsh,Zolfigol, Mohammad Ali
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p. 2311 - 2319
(2007/10/03)
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- The use of Nafion-H/NaNO2 as an efficient procedure for the chemoselective N-nitrosation of secondary amines under mild and heterogeneous conditions
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A combination of Nafion-H and sodium nitrite in the presence of wet SiO2 was used as an effective agent for the N-nitrosation of secondary amines under mild and heterogeneous conditions in good to excellent yields.
- Zolfigol, Mohammad Ali,Habibi, Davood,Mirjalili, BiBi Fatemeh,Bamoniri, Abdolhamid
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p. 3345 - 3349
(2007/10/03)
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- A simple and efficient method for the N-nitrosation of secondary amines with NaNO2-Ac2O under mild conditions
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Secondary amines can be easily converted into their corresponding nitroso derivations using NaNO2-Ac2O as a nitrosating agent in dichloromethane at room temperature with high yields.
- Hou, Jian-Ye,Wang, Yu-Lu,Wang, Jin-Ye
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p. 626 - 627
(2007/10/03)
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- Comparative study of nitroso group transfer in colloidal aggregates: Micelles, vesicles and microemulsions
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A kinetic study was carried out on nitroso group transfer from N-methyl-N-nitroso-p-toluenesulfonamide (MNTS) to different secondary amines: morpholine (MOR), piperazine (PIP), dimethylamine (DMA) and piperidine (PIPER) in micelles of dodecyltrimethylammonium bromide (LTABr) and in vesicles of dioxadecyltrimethylammonium chloride (DODAC). Amine nucleophiles were chosen on the basis of their hydrophobicity and basicity. The observed rate constant, kobs, shows opposite behavior in micelles and vesicular systems. kobs for micelle systems decreases as the surfactant concentration increases. This behavior can be interpreted according to the distribution of the reagents among the different pseudophases of the system and the physicochemical properties of the latter. It has been observed that the product of the rate constant in the micellar pseudophase and the distribution constant of the amine, k2mKmR2NH, retains a sequence similar to the reactivity observed in water. The differences observed can be explained on the basis of the different hydrophobicity of the amines and consequently different values of KmR2NH. In all cases a catalytic effect on the addition of vesicles was observed reaching a limiting value of kobs. The kinetic behavior can be explained quantitatively on the basis of a single pseudophase model, k2vKvR2NH in the vesicular systems of DODAC displays a variation which is analogous with the micellar systems but approximately 35 times greater, which in turn indicates the greater hydrophobic character of the vesicles of DODAC by comparison with the micelles of LTABr. In AOT/isooctane/water microemulsions we have found similar behavior where the product is approximately 22 times lower than in vesicles, indicating that the polarity of the interface of the microemulsions is greater than that of the micelles of LTABr and smaller than that of DODAC vesicles. The comparative analysis of the reactivities in the interface of the microemulsion and in an aqueous medium shows that the reactive position in the interface changes as the hydrophobic character of the amine varies.
- Garcia-Rio,Herves,Mejuto,Perez-Juste,Rodriguez-Dafonte
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p. 372 - 380
(2007/10/03)
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- Synthesis of methoxy-NNO-azoxyethene
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The first representative of the alkoxy-NNO-azoxy olefin series, viz., methoxy-NNO-azoxyethene, was synthesized by the pyrolysis of 1,1-bis(methoxy-NNO-azoxy)ethane.
- Zyuzin,Lempert,Nechiporenko
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p. 1431 - 1433
(2007/10/03)
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- Silica chloride/NaNO2 as a novel heterogeneous system for the nitrosation of secondary amines under mild conditions
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Secondary amines can be readily converted to their corresponding nitroso derivatives with a combination of silica chloride (I), wet SiO2 and sodium nitrite in dichloromethane at room temperature with moderate to excellent yields.
- Zolfigol, Mohammad Ali,Shirini, Farhad,Ghorbani Choghamarani, Arash
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p. 1809 - 1813
(2007/10/03)
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- Trichloroisocyanuric acid/NaNo2 as a novel heterogeneous system for the N-nitrosation of N,N-dialkylamines under mild conditions
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A combination of trichloroisocyanuric acid and sodium nitrite in the presence of wet SiO2 was used as an effective nitrosating agent for the nitrosation of N,N-dialkyl amines to their corresponding nitroso derivatives under mild and heterogeneous conditions in moderate to excellent yields.
- Zolfigol, Mohammad Ali,Choghamarani, Arash Ghorbani,Hazarkhani, Hassan
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p. 1002 - 1004
(2007/10/03)
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- Silica sulfuric acid/NaNO2 as a novel heterogeneous system for the chemoselective N-nitrosation of secondary amines under mild conditions
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Neat chlorosulfonic acid reacts with silica gel to give silica sulfuric acid in which sulfuric acid is immobilized on the surface of silica gel via a covalent bond. A combination of silica sulfuric acid and sodium nitrite in the presence of wet SiO2 was used as an effective nitrosating agent for the nitrosation of secondary amines to their corresponding nitroso derivatives under mild and heterogeneous conditions in excellent yields.
- Zolfigol, Mohammad Ali,Bamoniri, Abdolhamid
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p. 1621 - 1624
(2007/10/03)
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- Formation of N-nitrosamines and N-nitramines by the reaction of secondary amines peroxynitrite and other reactive nitrogen species: Comparison with nitrotyrosine formation
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Reactive nitrogen species, including nitrogen oxides (N2O3 and N2O4), peroxynitrite (ONOO-), and nitryl chloride (NO2Cl), have been implicated as causes of inflammation and cancer. We studied reactions of secondary amines with peroxynitrite and found that both N-nitrosamines and N- nitramines were formed. Morpholine was more easily nitrosated by peroxynitrite at alkaline pH than at neutral pH, whereas its nitration by peroxynitrite was optimal at pH 8.5. The yield of nitrosomorpholine in this reaction was 3 times higher than that of nitromorpholine at alkaline pH, whereas 2 times more nitromorpholine than nitrosomorpholine was formed at pH 2N·), which react with nitric oxide (·NO) or nitrogen dioxide (·NO2) to yield nitroso and nitro secondary amines, respectively. Reaction of morpholine with NO· and superoxide anion (O2·-), which were concomitantly produced from spermine NONOate and by the xanthine oxidase systems, respectively, also yielded nitromorpholine, but its yield was 2·- inhibited its formation. Reactions of morpholine with nitrite plus HOCl or nitrite plus H2O2, with or without addition of myeloperoxidase or horseradish peroxidase, also yielded nitration and nitrosation products, in yields that depended on the reactants. Tyrosine was nitrated easily by synthetic peroxynitrite, by NaNO2 plus H2O2 with myeloperoxidase, and by NaNO2 plus H2O2 under acidic conditions. Nitrated secondary amines, e.g., N-nitroproline, could be identified as specific markers for endogenous nitration mediated by reactive nitrogen species.
- Masuda, Mitsuharu,Mower, Howard F.,Pignatelli, Brigitte,Celan, Irena,Friesen, Marlin D.,Nishino, Hoyoku,Ohshima, Hiroshi
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p. 301 - 308
(2007/10/03)
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- An efficient method for N-nitrosation of secondary amines under mild and, heterogeneous conditions
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A combination of inorganic acidic salts or silica gel supported inorganic acids and sodium nitrite in the presence of wet SiO2 was used as an effective nitrosating agent for the nitrosation of secondary amines to their corresponding nitroso derivatives under mild and heterogeneous conditions in moderate to excellent yields. Mg(HSO4)2 and NaHSO4 are superior to all the aforementioned reagents in convenience, yield and purity of the isolated nitrosoamines.
- Zolfigol, Mohammad Ali,Ghaemi, Ezat,Madrakian, Elahe,Kiany-Borazjani, Maryam
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p. 2057 - 2060
(2007/10/03)
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- Efficient and chemoselective N-nitrosation of secondary amines under mild and heterogeneous conditions with sodium nitrite and oxalic acid two hydrate
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Secondary amines can be quantitatively converted to their corresponding nitroso derivatives with a combination of oxalic acid and sodium nitrite in dichloromethane at room temperature.
- Zolfigol, Mohammad Ali
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p. 905 - 910
(2007/10/03)
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- Liquid missile propellants in the former Soviet Union
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The liquid missile propellant unsymmetrical dimethylhydrazine (UDMH) is a very toxic and persistent organic chemical that was widely used in the missile industry of the former Soviet Union. Only in the last few years have Russian authorities acknowledged the dangers of this fuel to people and nature. To date, little has been done for the transition towards fuels with a lower toxicity. This paper describes the chemical nature of UDMH, and considers its potential impacts on nature and human health. Copyright (C) 1999 ElsevierScience Ltd. All rights reserved.
- Fedorov
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p. 157 - 161
(2007/10/03)
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- Decomposition mechanism of dinitramide onium salts
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Thermal decomposition of dinitramide onium salts proceeds via the dissociative mechanism when pKa of the base is lower than 5.0 and via the monomolecular decay of the anion at pKa > 7.0. On going from the melt to the solid state, the reaction mechanism does not change, and the rate decreases by 1-2 orders of magnitude. No anomalous effects inherent in dinitramide metal salts in the solid phase are observed during decomposition of onium salts.
- Pavlov,Nazin
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p. 1848 - 1850
(2007/10/03)
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- Effect of Ceramics Radiation on Nitrosodimethylamine Production
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The effects of ceramics radiation on nitrosation of dimethylamine with nitrile in citrate buffer of pH 3.4 was studied using a ceramics heater.The rate constant of nitrosodimethylamine (NDMA) production under the irradiation conditions decreased by 81percent from the non-irradiated reaction, and that of nitrite degradation increased 1.5-fold.The activation energy for NDMA production and nitrile degradation after 4 h of irradiation decreased by 53 and 73percent of the non-irradiated reactions, respectively.It was estimated that the hydration effects of the ceramics radiation were concerned in the repression of NDMA production and the acceleration of nitrite degradation.
- Kohashi, Masahiro,Keitoko, Noriko,Matsu-ura, Yoshiki,Watanabe, Tatsuo
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p. 2193 - 2197
(2007/10/03)
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- Mechanisms of Nitramine Thermolysis
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The thermal decomposition of a number of nitramines was studied in dilute solution and in the melt.The nitramines included acyclic mononitramines , cyclic mononitramines , cyclic dinitramines , and 1,3,5-trinitro-1,3,5-triazocyclohexane (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), hexanitrohexaazaisowurtzitane (HNIW), and 1,3,3-trinitroazetidine (TNAZ).For the acyclic and cyclic mono- and dinitramines, the corresponding nitrosamines were the only or major condensed-phase product.Kinetics and activation parameters were determined for the thermolysis of dilute solutions (0.01-1.0 wtpercent) over the range 200-300 deg C.The thermolyses were found to be first-order with the rate constants unaffected by the use of deuterated solvent.As the nitramines became more complex than dimethylnitramine (DMN), the rate of decomposition increased and the product distribution became more complex.As the length of the aliphatic chain increased (DMN DEN DPN), the rate of thermolysis increased, yet nitrosamine remained the only observed condensed-phase product.When a secondary carbon was attached to the N-nitramine (DIPN) rather than the primary (DPN), the rate of decomposition increased and a new condensed-phase product was observed.Among the cyclic nitramines, the rate of decomposition increased as the number of NNO2 groups increased (NPIP pDNP; NPyr DNI; mDMP RDX).The position of the nitramine groups affected the decomposition: meta NNO2 groups (mDNP) decomposed faster than para (pDNP).Ring strain decreased stability: mDNP DNI; HMX RDX.In complex nitramines, the increase in decomposition rate, the appearance of new products, and the change in the relative importance of nitrosamine and of N2 and N2O are attributed to new decomposition routes available to them.However, since complex nitramines (e.g.RDX) maintain first-order kinetics and since most have activation energies in the range of 40-50 kcal/mol, it is belived that the triggering mechanism remains N-NO2 homolysis.Intramolecular hydrogen transfer is also considered an important mode of nitramine decomposition.
- Oxley, J. C.,Kooh, A. B.,Szekeres, R.,Zheng, W.
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p. 7004 - 7008
(2007/10/02)
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- Gas-Phase Reactions of (CH3)2N Radicals with NO and NO2
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The absolute rate constants for the reactions of (CH3)2N radicals with NO and NO2 were determined in the gas phase and at room temperature by using the very low pressure reactor (VLPR) technique.The rates were k(CH3)2N + NO = (8.53 +/- 1.42) x 1E-14 Cm3 molecule-1s-1 and k(CH3)2N + NO2 = (9.08 +/- 1.36) x 1E-13 cm3 molecule-1s-1.The reaction with NO2 proceeds via two competitive pathways: the recombination patway (CH3)2N + NO2 -> (CH3)2NNO2, with a rate constant k2a = (3.18 +/- 0.48) x 1E-13 cm3molecule-1s-1, and the oxidation patway (CH3)2N + NO2 -> (CH3)2NONO* -> (CH3)2NO + NO, with a rate constant k2b = (6.36 +/- 0.74) x 1E-13 cm3molecule-1s-1.The oxidation pathway is ca. 2.2 times faster than the recombination one, and the ratio k2a/k2b = 0.45 +/- 0.15.Conventional transition state theory analysis indicates that the involved transition states are loose, with the NN or bond lengths equal to ca. 2.5 Angstroem.
- Lazarou, Yannis G.,Kambanis, Kyriakos G.,Papagiannakopoulos, Panos
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p. 2110 - 2115
(2007/10/02)
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- Nitrosations with hydrazine derivative, VI: Novel reaction of oral antidiabetics of the sulfonylsemicarbazide type under nitrosating conditions
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Oral antidiabetics of the sulfonylsemicarbazide type like Tolazamide (1) and Glisoxepide (2) were transformed under mild nitrosating conditions, even nearly physiological in vitro conditions, to sulfonyl triazenes 3a, b by a novel reaction pathway. Model compounds with N4-Acyl-semicarbazide structure 4 showed different reaction behaviour yielding carbonamides 5 and nitrosamines 6.
- Hanefeld,Hartmann
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p. 925 - 927
(2007/10/02)
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- Transfer of the Nitroso Group in Water/AOT/Isooctane Microemulsions: Intrinsic and Apparent Reactivity
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The kinetics of the transfer of the nitroso group from N-methyl-N-nitroso-p-toluenesulfonamide to each of seven secondary amines (piperazine, N-methylbenzylamine, piperidine, dimethylamine, morpholine, pyrrolidine, and diisopropylamine) was studied using a wide variety of water/AOT/isooctane microemulsions as reaction media.The diverse kinetic behavior of the various amines can be explained quantitatively on the basis of a single model taking into account the distribution of the amine among the aqueous and isooctane phases and their mutual interface; the reaction itself always takes place at the interface.The relative reactivities of the amines are discussed in comparison with the order observed in water.
- Garcia-Rio, Luis,Leis, J. Ramon,Pena, M. Elena,Iglesias, Emilia
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p. 3437 - 3442
(2007/10/02)
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- Thermal Decomposition of Nitramines: Dimethylnitramine, Diisopropylnitramine, and N-Nitropiperidine
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Kinetics and activation parameters of the solution thermolysis of nitramines dimethylnitramine, diisopropylnitramine, and N-nitropiperidine were determined over the temperature range 200-300 deg C.Each formed the corresponding nitrosamine as the only, or major, condensed-phase product.For dimethylnitramine the products were completely characterized.The observations of a large positive activation volume in the thermolysis of dimethylnitramine and of the slowing of the decomposition reaction with increased solvent viscosity both suggest that the rate-determining step is homolysis, the N-NO2 bond being the most obvious point for this.Nitrosamines could be produced by this route; however, when doubly 15N-labeled dimethylnitramine was heated with unlabeled dimethylnitramine, little scrambling of the label in the reactant was observed.Label scrambling was observed in the nitrosamine but could have resulted from subsequent N-NO homolysis.Scrambling of the label in the product gases and the observation of a kinetic isotope effect when perdeuterated dimethylnitramine was decomposed were explained in terms of a second decomposition route involving transfer of hydrogen from the α carbon to one of the NO2 oxygens.
- Oxley, J. C.,Hiskey, M.,Naud, D.,Szekeres, R.
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p. 2505 - 2509
(2007/10/02)
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- Formation of Nitrosamines in Alkaline Conditions: a Kinetic Study of the Nitrosation of Linear and Cyclic Secondary Amines by Nitroalkanes
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A study has been made of the nitrosation of sixteen secondary amines, six alkylamines (dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, diisobutylamine) and ten cyclic secondary amines (2-methylaziridine, azetidine, pyrrolidine, piperidine, 2-methylpiperidine, homopiperidine, heptamethyleneimine, piperazine, 1-methylpiperazine and morpholine) by nitropropane and nitrobutane in a strongly basic medium (-> = 0.1 mol dm-3).The nitrites were not formed in situ (i.e. in the actual bulk of the reaction medium) but rather were isolated,purified and used in pure form.The rate equation (i) was found v = k2obs (i).The fitting of the experimental results to the Taft correlation points to a nucleophilic attack on nitrite esters by the amines.Analysis of the log k2/pKa and log k2/Ei(v) correlations indicates orbital control of the reactions studied.These results, together with the fact that the reactivity of the different amines diminishes ostensibly when the values of the 13C-H nuclear spin coupling constant in the series of corresponding cycloalkanes increase, show that the overall hybridization of the nitrogen atom in the cycle changes from sp2 in the triangular nucleophile methylaziridine to sp3 in larger cycles.The results obtained at different temperatures and with water-tetrahydrofuran media, together with a study of isotope effects suggest that these reactions occur through a highly ordered transition state and that the role of solvation should not be overlooked.
- Calle, Emilio,Casado, Julio,Cinos, Jose L.,Mateos, Francisco J. Garcia,Tostado, Manuel
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p. 987 - 991
(2007/10/02)
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- Thermal Decomposition of Energetic Materials: Temporal Behaviors of the Rates of Formation of the Gaseous Pyrolysis Products from Condensed-Phase Decomposition of Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine
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The temporal behaviors of the rates of formation of the gaseous products from the pyrolysis of HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) are determined by simultaneous thermogravimetric modulated beam mass spectrometry (STMBMS).The gaseous products formed from the pyrolysis of HMX, and its deuterium- and 15NO2-labeled analogues, between 210 and 235 deg C are H2O, HCN, CO, CH2O, NO, N2O, CH3NHCHO, (CH3)2NNO, 1-nitroso-3,5,7-trinitro-1,3,5,7-tetrazocine (ONTNTA), and their isotopic analogues.In addition, a nonvolatile residue (NVR) is formed.The NVR is a polyamide that decomposes between 250 and 780 deg C producing NH3, HCN, HNCO, H2NCHO, CH3NHCHO, and products that include long-chain hydrocarbons.The temporal behaviors of the rates of gas formation of the pyrolysis products along with the macroscopic and microscopic structure of the NVR indicate that complex physical processes and chemical mechanisms within the condensed phase of HMX control the decomposition.The temporal behaviors of the rates of gas formation show induction, acceleratory, and decay stages that are characteristic of either condensed-phase or autocatalytic decomposition.The NVR is composed of broken ellipsoidal shells whose diameters range from 0.3 to 5 μm.The shells appear to be remnants of gas-filled bubbles that are formed within the HMX particles during the pyrolysis.The pressures within the gas bubbles may exceed 7 MPa.The major portion of the pyrolysis products observed in the experiments comes from gases that have been contained within the bubbles.Gas released earlier in the decomposition are contained in smaller bubbles and therefore are formed under higher pressure conditions.This results in the variation of the relative rates of formation of the gas products.For example, the ratios of the rates of formation of CH2O to N2O is between 0.7 and 0.8 during the induction stage, decreases to a minimum of 0.36 during the acceleratory stage, and increases to ca. 1 at the end of the decay stage.Variations in the relative rates of formation of the other products are also observed.The changes in the rates of release of products from the initial to final stages of the decomposition indicate that different species are formed when the pyrolysis products are contained at different pressures.The effects of these different physical processes on the relation between the observed pyrolysis products and the underlying chemical decomposition mechanisms are discussed.
- Behrens, Richard
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p. 6706 - 6718
(2007/10/02)
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- Reactions of trifluoroamine oxide: A route to acyclic and cyclic fluoroamines and N-nitrosoamines
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Acyclic secondary fluoroamines and N-nitrosoamines R2NF and R2NNO (R = CH3, C2H5, n-C3H7, i-C3H7, n-C4H9, i-C4H9, c-C6H11) and saturated nonaromatic heterocyclic fluoroamines and N-nitrosoamines R NF and R NNO [R = c-C4H8, c-C5H10, 2,6-(CH3)2-c-C5H8, 2,2,6,6-(CH3)4-c-C5H6] were prepared by reacting trifluoroamine oxide (NF3O) with the respective amine at ≤0 °C in a 1:2 molar ratio. The amine hydrofluoride salts are also formed. Trifluoroamine oxide is a very effective fluorinating and nitrosating reagent and provides an excellent route to >NF- and >NNO-containing compounds. With PF5, 2,2,6,6-(CH3)4-c-C5H6NFgave [CH2CH2CH2C(CH3)2N +=C(CH3)2]PF6-.
- Gupta, Om Dutt,Kirchmeier, Robert L.,Shreeve, Jean'ne M.
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p. 2383 - 2386
(2007/10/02)
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- Kinetic Studies on the Influence of Micellar Aggregates upon the Hydrolysis and Transnitrosation Reactions of N-methyl-N-nitrosotoluene-p-sulphonamide
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The basic hydrolysis of N-methyl-N-nitrosotoluene-p-sulphonamide and its transnitrosation reaction with secondary amines (sarcosine and dimethylamine) have been studied in the presence of cationic, anionic, and non-ionic micelles.The results show that the electric charge of the nucleophile is essential for the understanding of the micellar effects, which can be quantitatively rationalized on the basis of the pseudophase kinetic model.Thus the reaction with negatively charged nucleophiles is inhibited by both anionic and non-ionic surfactants, whereas cationic micelles increase the reaction rate, which passes through a maximum.The reaction between the substrate and a neutral nucleophile is, however, inhibited by all three classes of surfactant.
- Castro, Albino,Leis, J. Ramon,Pena, M. Elena
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p. 1221 - 1225
(2007/10/02)
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- Thermal Decomposition of Dimethylnitramine and Dimethylnitrosamine by Pulsed Laser Pyrolysis
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Pyrolysis of dimethylnitramine (DMNA) and dimethylnitrosamine (DMNO) was carried out in a flow system over the temperature range 800-900 K using pulsed infrared laser heating, via SF6 in a 250-Torr bath of CO2 and radical scavanger.Arrhenius parameters for DMNO and DMNA composition were log k(s-1)=(15.8+/-1.1)-(50.0+/-3.4)/2.3RT and (13.5+/-0.6)-(37.4+/-2.5)/2.3RT, respectively.The former set of parameters is consistentwith simple bond scission as the rate-limiting step; the latter set, which was produced with different scavengers, temperature standards, and varying amounts of added NO as a radical trap, is not consistent with simple bond scission.The experimental reaults can be reproduced via a mechanistic numerical model in which N-NO2 bond scission and nitro-nitrite rearrangement are competitive initial steps and the displacement of NO2 from DMNA by NO is included as a low-temperature route to DMNO.
- Nigenda, S. Esther,McMillen, Donald F.,Golden, David M.
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p. 1124 - 1130
(2007/10/02)
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- Nitrosamines from N,N-Disubstituted Hydrazines Via Hydrazones of Dinitroformaldehyde and Ethyl Nitroglyoxylate
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N,N-Dialkyl, diaryl, and arylalkyl hydrazones of dinitroformaldehyde were obtained from hydrazines and either tetranitromethane (TNM) or iodotrinitromethane (ITM) and gave nitrosamines on irradiation at 350 nm in acetone for several days.Similar N,N-disubstituted hydrazones of ethyl nitroglyoxylate were obtained from the hydrazines and either ethyl dinitroiodoacetate (DNIA) or ethyl dinitrobromoacetate (DNBA) but were neither thermal nor photochemical precursors to nitrosamines, coproducts obtained in minor amounts.Explanations for the formations of the hydrazones and nitrosamines were offered.
- Boyer, Joseph H.,Krishnan, Ashwin M.
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p. 201 - 213
(2007/10/02)
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- DISPLACEMENT OF O- VERSUS N-SUBSTITUENTS FROM NITROSAMINE-DERIVED DIAZENIUM IONS BY THREE DIVERGENT MECHANISMS
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Cations formed on O-coordination of N-nitrosodimethylamine with different electrophiles decomposed by different routes: dissociation of Me2N=NOCMe3(1+) ClO4(1-); regeneration of free nitrosamine by nucleophilic cleavage of the O-Si bond in Me2N=NOSiMe3(1+) CF3SO3(1-); and nucleophilic displacement of the N-methyl groups from Me2N=NOSO2CF3(1+) CF3SO3(1-).
- Ohannesian, Lena,Keefer, Larry K.
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p. 2903 - 2906
(2007/10/02)
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- Nitrosamines from N,N-Disubstituted Hydrazines
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Photolysis of nitro hydrazones (from N,N-disubstituted hydrazines and tetranitromethane) gave nitrosamines.
- Boyer, Joseph H.,Krishnan, Ashwin M.
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p. 715 - 716
(2007/10/02)
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- Preparation of a Thallium(I) Diazotate. Structure, Physicochemical Characterization, and Conversion to Novel N-Nitroso Compounds
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Thallium(I) (E)-methanediazotate (4) has been prepared and characterized.In contrast to previously reported methanediazotates, 4 is a highly crystalline material whose physical properties suggest a considerable degree of covalency: it is readily soluble in certain nonpolar solvents; it melts reversibly at a low temperature; it is monomeric and nonconducting in chloroform solution; and ions corresponding to the formula Tl(CH3N2O).+ are found in the electron impact mass spectrum.The crystal structure of 4 revealed Tl-O distances as short as 2.52(3) Angstroem and confirmed the anti stereochemistry; the monoclinic unit cell, space group P21/c-C52h (No. 14), had a=13.233(6) Angstroem, b=11.594(4) Angstroem, c=6.253(2) Angstroem, β=119.45(3)o, V=871.5(6) Angstroem3, and Z=8.The compound's advantageous stability and solubility properties provide important new opportunities for probing the solution chemistry of the alkanediazotates.As an illustration of this potential, 4 has been converted in homogeneous media to unusual N-nitroso compounds including a quaternary ammonium salt of a primary nitrosamine, an isotopic variant of dimethylnitrosamine in which the methyl group syn to the oxygen is fully deuteriated, and the less stable Z conformer of methylbenzylnitrosamine.In contrast to 4 , its Z stereoisomer has until now defied isolation but has been identified in situ by reaction with iodomethane-d3 to produce (E)-methyl(methyl-d3)nitrosamine.
- Keefer, Larry K.,Wang, Shui-mei,Anjo, Takako,Fanning, James C.,Day, Cynthia S.
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p. 2800 - 2806
(2007/10/02)
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