- Synthesis and characterization of secondary nitrosamines from secondary amines using sodium nitrite and p-toluenesulfonic acid
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We synthesized nitrosamines (R2N-NO) with R = iPr (1), nPr (2), nBu (3), and hydroxyethyl (4) from the amine using sodium nitrite/p-toluenesulfonic acid in CH2Cl2. The rate of formation of 1-4 increases in the direction iPr2CH2OH. Compounds 1-3 were obtained as colorless solids, whereas 4 is a bright yellow liquid. Compounds 1-4 were characterized by elemental analysis, MS, IR, and multinuclear NMR (1H, 13C, and 15N) spectroscopies. Additionally, we measured the UV/Vis spectra of all compounds, which show maxima of absorption at approximately 221 nm and molar extinction coefficients between 3043 and 4859 Lmol-1cmr-1. We calculated the optimized structures of 1-4 (B3LYP/6-311+G(d,p)) and computed the NMR spectroscopic chemical shifts and infrared frequencies. Furthermore, we carried out a natural bond orbital (NBO) analysis of the nitrosamine moiety. Lastly, the compounds described in this work are valuable starting materials for the synthesis of 2-tetrazenes with potential interest to replace highly toxic hydrazines in rocket propulsion.
- Sabat, Carles Mir,Delalu, Henri
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p. 674 - 678
(2015/07/01)
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- Synthesis of N,N-dialkylnitramines from secondary ammonium nitrates in liquid or supercritical carbon dioxide
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An efficient explosion-proof method was developed for the preparation of N,N-dialkylnitramines by treatment of dialkylammonium nitrates with a mixture of nitric acid and acetic anhydride in the presence of ZnCl2 in liduid or supercritical carbon dioxide.
- Kuchurov,Fomenkov,Zlotin
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experimental part
p. 2058 - 2062
(2011/01/08)
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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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- Reactivity of Nucleophilic Nitrogen Compounds towards the Nitroso Group
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We discuss the reactivity of 43 nucleophilic nitrogen compounds towards the nitroso group of N-methyl-N-nitrosotoluene-p-sulfonamide (MNTS), and in some cases with alkyl nitrites.The series of nucleophiles considered is structurally very varied, includes members exhibiting the alpha effect, and covers 8 pKa units and a range of reactivities of almost five orders of magnitude.The values of solvent isotope effects and activation parameters have been measured and throw light on the structure of the transition states involved.Reactivities do not correlate well with thebasicity of the nucleophile, largely owing to the behaviour of primary amines, ammonia and nucleophiles with an alpha effect.Application of the curve crossing model suggests a relationship with vertical ionization potentials.The relationship with Ritchie's N+ scale is discussed, and interesting correlations with the reactivities of the same nucleophiles in various other chemical processes are noted.
- Garcia-Rio, Luis,Iglesias, Emilia,Leis, J. Ramon,Pena, M. Elena,Rios, Ana
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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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- 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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- Structure-reactivity correlations in nitrosation reactions of secondary amines by alkyl nitrites in basic media
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A study was conducted on the influence of the basic character of different secondary amines on the rate of their nitrosation reactions by propyl and 2-hydroxyethyl nitrites in basic medium (pH = 9-12).For the series of the five structurally similar amines studied (morpholine, piperazine, N-methylpiperazine, piperidine, and pyrrolidine) an excellent linear correlation was observed between the values of the logarithm of the second order rate constant - corresponding to the attack of the alkyl nitrites on the unprotonated amines - and the pKa of these amines.These results, together with the scattering of linearity when including non structurally similar substrates, confirm that the reactions studied are mainly orbital-controlled and have permitted us a rough estimation of the vertical Ionization Potentials, vIP, of piperazine, N-methylpiperazine and morpholine.The kinetic study of nitrosation reaction of N-methylaniline has led to results from which, when compared with those obtained referring to the five above-mentioned substrates, it is possible to infer again that the reactivity of the nitrosatable substrates studied does not depend exclusively on their pKa.
- Casado, Julio,Castro, Albino,Lopez-Quintela, M. Arturo,Lorenzo-Barral, M. Francisco
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p. 401 - 404
(2007/10/02)
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