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1.
This work is aimed at studying HNO2 generation by bubbling NO in HNO3 solution. The formation and decomposition of HNO2 depend on the 2NO+HNO3+H2O3HNO2 reaction. During the HNO2 generation, the HNO3 concentration was kept constant. The influence of HNO3 concentration, temperature, NaNO3 concentration and NO bubbling rate was studied. Its possible application in the PUREX process was evaluated.  相似文献   

2.
Investigation of the formation of complex reaction products in the gas-phase system O3/NO2/(Z)-2-butene by combination of linear reactors with IR. matrix and microwave Stark Spectroscopy is reported. Besides the polyatomic products observed earlier in the gas-phase ozonolysis of (Z)-2-butene, the following products were identified; N2O5, HNO3, HNO4, CH3NO2, CH3ONO, CH3COONO2 and CH3COO2NO2 (peroxyacetyl nitrate, PAN). Matrix IR. spectra of N2O5, HNO3. CH3COONO, CH3COONO2 required for reference purposes are presented. It is shown that PAN-formation occurs already in the absence of light. A reaction scheme is proposed for explanation of the observed complex NOx-containing products, which assumes methyldioxirane as a central intermediate. Particular reaction steps of the scheme will be discussed, including thermochemical estimates of reaction enthalpies.  相似文献   

3.
The rate of reaction between NO and HNO3 and the rate of thermal decomposition of HNO3 have been measured by FTIR spectroscopy. The measurements were made in a teflon lined batch reactor having a surface to volume ratio of 14 m?1. During the experiments, with initial HNO3 concentrations between 2 and 12 ppm and NO concentrations between 2 and 30 ppm, a reactant stoichiometry of unity and a first order NO and HNO3 dependence were confirmed. The observed rate constant for the reaction at 22°C and atmospheric pressure was determined to 1.1 (±0.3) 10?5 ppm?1 min?1. At atmospheric pressure, HNO3 decomposes into NO2 and other products with a first order HNO3 dependence and with a rate constant of 2.0 (±0.2) 10?3 min?1. The apparent activation energy for the decomposition is 13 (±4) kJ mol?1.  相似文献   

4.
Cs4[La(NO3)6](NO3) · HNO3: The First Nitric Acid Adduct of a Ternary Alkali Lanthanide Nitrate In the crystal structure of Cs4[La(NO3)6](NO3). HNO3 (monoclinic, P21/c, Z = 2, a = 787.3(2); b = 1353.0(3); c = 1141.8(7) pm; β = 94,37(3)°) La3+ has a coordination number of twelve (six bidentate nitrate ligands). The structure may be viewed at as a layer structure: Layers of the composition [Cs(1)4La2(NO3)12]2?, and [Cs(2)4(NO3)2(HNO3)2]2+ are stacked alternatively in the [100] direction.  相似文献   

5.
Haloacetyl, peroxynitrates are intermediates in the atmospheric degradation of a number of haloethanes. In this work, thermal decomposition rate constants of CF3C(O)O2NO2, CClF2C(O)O2NO2, CCl2FC(O)O2NO2, and CCl3C(O)O2NO2 have been determined in a temperature controlled 420 l reaction chamber. Peroxynitrates (RO2NO2) were prepared in situ by photolysis of RH/Cl2/O2/NO2/N2 mixtures (R = CF3CO, CClF2CO, CCl2FCO, and CCl3CO). Thermal decomposition was initiated by addition of NO, and relative RO2NO2 concentrations were measured as a function of time by long-path IR absorption using an FTIR spectrometer. First-order decomposition rate constants were determined at atmospheric pressure (M = N2) as a function of temperature and, in the case of CF3C(O)O2NO2 and CCl3C(O)O2NO2, also as a function of total pressure. Extrapolation of the measured rate constants to the temperatures and pressures of the upper troposphere yields thermal lifetimes of several thousands of years for all of these peroxynitrates. Thus, the chloro(fluoro)acetyl peroxynitrates may play a role as temporary reservoirs of Cl, their lifetimes in the upper troposphere being limited by their (unknown) photolysis rates. Results on the thermal decomposition of CClF2CH2O2NO2 and CCl2FCH2O2NO2 are also reported, showing that the atmospheric lifetimes of these peroxynitrates are very short in the lower troposphere and increase to a maximum of several days close to the tropopause. The ratio of the rate constants for the reactions of CF3C(O)O2 radicals with NO2 and NO was determined to be 0.64 ± 0.13 (2σ) at 315 K and a total pressure of 1000 mbar (M = N2). © 1994 John Wiley & Sons, Inc.  相似文献   

6.
This qualitative study examines the response of the novel energetic material ammonium dinitramide (ADN), NH4N(NO2)2, to thermal stress under low heating rate conditions in a new experimental apparatus. It involved a combination of residual gas mass spectrometry and FTIR absorption spectroscopy of a thin cryogenic condensate film resulting from deposition of ADN pyrolysis products on a KCl window. The results of ADN pyrolysis were compared under similar conditions with the behavior of NH4NO3 and NH2NO2 (nitramide), which served as reference materials. NH4NO3 decomposes into HNO3 and NH3 at 182°C and is regenerated on the cold cryostat surface. HNO3 undergoes presumably heterogeneous loss to a minor extent such that the condensed film of NH4NO3 contains occluded NH3. Nitramide undergoes efficient heterogeneous decomposition to N2O and H2O even at ambient temperature so that pyrolysis experiments at higher temperatures were not possible. However, the presence of nitramide can be monitored by mass spectrometry at its molecular ion (m/? 62). ADN pyrolysis is dominated by decomposition into NH3 and HN(NO2)2 (HDN) in analogy to NH4NO3, with a maximum rate of decomposition under our conditions at approximately 155°C. The two vapor phase components regenerate ADN on the cold cryostat surface in addition to deposition of the pure acid HDN and H2O. Condensed phase HDN is found to be stable for indefinite periods of time at ambient temperature and vacuum conditions, whereas fast heterogeneous decomposition of HDN at higher temperature leads to N2O and HNO3. The HNO3 then undergoes fast (heterogeneous) decomposition in some experiments. Gas phase HDN also undergoes fast heterogeneous decomposition to NO and other products, probably on the internal surface (ca. 60°C) of the vacuum chamber before mass spectrometric detection. © 1993 John Wiley & Sons, Inc.  相似文献   

7.
The experimental results on decomposition and combination reactions involving O3, HNO3, NH3, C2N2, and NO2Cl over extended temperature and pressure ranges are compared with the deductions from RRKM calculations. Quantitative fits of the data over the entire range are possible only if the external (overall) rotations are assumed to be involved in the reactions. Recommended rate constants for the reactions O + O2 + N2 → O3 + N2 and OH + NO2 + N2 → HNO3 + N2 are presented.  相似文献   

8.
Crystalline NO[Mn(NO3)3] ( I ) and (NO)2[Co(NO3)4] ( II ) were synthesized by reaction of the corresponding metal and a liquid N2O4/ethylacetate mixture. I is orthorhombic, Pca21, a = 9.414(2), b = 15.929(3), c = 10.180(2) Å, Z = 4, R1 = 0.0286. II is monoclinic, C2/c, a = 14.463(3), b = 19.154(4), c = 13.724(3) Å, β = 120.90(3), Z = 12, R1 = 0.0890. Structure I consists of [Mn(NO3)3] sheets with NO+ cations between them. Two types of Mn atoms have CNMn = 7 and 8. Structure II is ionic containing isolated [Co(NO3)4]‐anions and NO+ cations with CNCo = 8. Crystals of Mn(NO3)2 ( III ) and Co(NO3)2 ( IV ) were obtained by concentration of metal nitrate hydrate solutions in 100% HNO3 in a desiccator with P2O5. III is cubic, Pa 3, a = 7.527(2) Å, Z = 4, R1 = 0.0987. IV is trigonal, R 3, a = 10.500(2), c = 12.837(3) Å, Z = 12, R1 = 0.0354. The three dimensional structure III is isotypic to the strontium and barium dinitrates. Structure IV contains a three dimensional network of interconnected Co(NO3)6/3 units with a distorted octahedral coordination environment of Co atoms. General correlations between central atom coordination and coordination modes of NO3 groups are discussed.  相似文献   

9.
The kinetics of the gas-phase reaction of the NO3 radical with naphthalene have been investigated at 150 torr O2 + 590 torr N2 and 600 torr O2 + 140 torr N2 at 298 ± 2 K. Relative rate measurements were carried out in reacting NO3? N2O5-naphthalene-propene-O2? N2 mixtures by longpath Fourier transform infrared absorption spectroscopy. A rate constant ratio for the reactions of O2 and NO2 with the NO3-naphthalene adduct of k/k < 4 × 10?7 was obtained from the competition between O2 and NO2 for reaction with the NO3-naphthalene adduct and thermal decomposition of the adduct back to reactants. Atmospheric pressure ionization MS/MS measurements of the nitronaphthalene products of the NO3 radical-initiated reaction of naphthalene are consistent with the proposed reaction mechanism, and the atmospheric implications of the data are discussed. © 1994 John Wiley & Sons, Inc.  相似文献   

10.
The reactions of naphthalene in N2O5? NO3? NO2? N2? O2 reactant mixtures have been investigated over the temperature range 272–297 K at ca. 745 torr total pressure and at 272 K and ca. 65 torr total pressure using long pathlength Fourier transform infrared absorption spectroscopy. 2,3-Dimethyl-2-butene was added to the reactant mixtures at 272 K to rapidly scavenge the NO3 radicals both initially present in the added N2O5 and formed from the thermal decomposition of N2O5 during the reactions. The data obtained in the presence and absence of added 2,3-dimethyl-2-butene showed that napthalene undergoes initial reaction with the NO3 radical to form an NO3-naphthalene adduct, which either rapidly decomposes back to the reactants (at a rate of ca. 5 × 105 s?1 at 298 K) or reacts exclusively with NO2 to form products. When NO3 radicals, N2O5 and NO2 are in equilibrium, this overall process is kinetically equivalent to reaction of naphthalene with N2O5, and previous kinetic and product studies have indeed assumed the reactions of naphthalene and alkyl-substituted naphthalenes in N2O5? NO3? NO2? air mixtures to be with N2O5, and not with NO3 radicals.  相似文献   

11.
Crystalline NO2[Fe(NO3)4] was obtained by dehydration of a solution of Fe(NO3)3 in 100 % HNO3 and subsequent sublimation. NO2[Zr(NO3)5] was synthesized by reaction of ZrCl4 with N2O5 followed by sublimation in vacuum. X‐ray single crystal structure determination showed both compounds to consist of nitronium cations, NO2+, and nitratometalate anions. N‐O distances in the linear NO2+ cations are in the range of 1.08—1.13Å. In both [Fe(NO3)4] and [Zr(NO3)5] anions, all nitrate groups are coordinated bidentately with average M‐O distances 2.134 and 2.293Å, respectively. Taking into account the position of N atoms around the M atoms, the arrangement of nitrate groups can be described as tetrahedral for the Fe complex and trigonal‐bipyramidal for the Zr complex. There are four shortest N(nitronium)····O(nitrate group) contacts with average distances of 2.705 and 2.726Å in NO2[Fe(NO3)4] and 2.749Å in NO2[Zr(NO3)5]. Nitronium pentanitratohafnate is isotypic to the zirconium complex.  相似文献   

12.
The equilibrium constant, Keq of the reaction NO2 + NO3 + M 2 N2O5 + M has been determined for a small range of temperatures around room temperature in air at 740 torr by direct spectroscopical measurements of NO2, NO3, and N2O5. At 298 K, Keq was determined as (3.73 ± 0.61) × 10−11 cm3 molecule−1. Averaging this and 11 other independent evaluations of Keq yields Keq = (3.31 ± 0.82) × 10−11 cm3 molecule−1, where the uncertainty is given as one standard deviation. The kinetics of the O3/NO2/N2O5/NO3/ air system was studied in a static chamber at room temperature and 740 torr total pressure. Evidence of a unimolecular decay reaction of NO3, NO3 → NO + O2, was found and its rate coefficient was estimated as (1.6 ± 0.7) × 10−3 s−1 at 295 ± 2 K.  相似文献   

13.
The zirconium nitrate complexes (NO2)[Zr(NO3)3(H2O)3]2(NO3)3 (1), Cs[Zr(NO3)5] ((2), (NH4)[Zr(NO3)5](HNO3) (3), and (NO2)0.23(NO)0.77[Zr(NO3)5] ((4) were prepared by crystallization from nitric acid solutions in the presence of H2SO4 or P2O5. The complexes were characterized by X-ray diffraction. The crystal structure of 1 consists of nitrate anions, nitronium cations, and [Zr(NO3)3(H2O)3]+ complex cations in which the ZrIV atom is coordinated by three water molecules and three bidentate nitrate groups. The coordination polyhedron of the ZrIV atom is a tricapped trigonal prism formed by nine oxygen atoms. The island structures of 2 and 3 contain [Zr(NO3)5]? anions and Cs+ or NH4 + cations, respectively. In addition, complex 3 contains HNO3 molecules. Complex 4 differs from (NO2)[Zr(NO3)5] in that three-fourth of the nitronium cations in 4 are replaced by nitrosonium cations NO+, resulting in a decrease in the unit cell parameters. In the [Zr(NO3)5]? anion involved in complexes 2–4, the ZrIV atom is coordinated by five bidentate nitrate groups and has an unusually high coordination number of 10. The coordination polyhedron is a bicapped square antiprism.  相似文献   

14.
An unusual heterobimetallic bis(triphenylphosphane)(NO2)AgI–CoIII(dimethylglyoximate)(NO2) coordination compound with both bridging and terminal –NO2 (nitro) coordination modes has been isolated and characterized from the reaction of [CoCl(DMGH)2(PPh3)] (DMGH2 is dimethylglyoxime or N,N′‐dihydroxybutane‐2,3‐diimine) with excess AgNO2. In the title compound, namely bis(dimethylglyoximato‐1κ2O,O′)(μ‐nitro‐1κN:2κ2O,O′)(nitro‐1κN)bis(triphenylphosphane‐2κP)cobalt(III)silver(I), [AgCo(C4H7N2O2)2(NO2)2(C18H15P)2], one of the ambidentate –NO2 ligands, in a bridging mode, chelates the AgI atom in an isobidentate κ2O,O′‐manner and its N atom is coordinated to the CoIII atom. The other –NO2 ligand is terminally κN‐coordinated to the CoIII atom. The structure has been fully characterized by X‐ray crystallography and spectroscopic methods. Density functional theory (DFT) and time‐dependent density functional theory (TD‐DFT) have been used to study the ground‐state electronic structure and elucidate the origin of the electronic transitions, respectively.  相似文献   

15.
This work analyzed the thermal decomposition of ammonium nitrate (AN) in the liquid phase, using computations based on quantum mechanics to confirm the identity of the products observed in past experimental studies. During these ab initio calculations, the CBS‐QB3//ωB97XD/6–311++G(d,p) method was employed. It was found that one of the most reasonable reaction pathways is HNO3 + NH4+ → NH3NO2+ + H2O followed by NH3NO2+ + NO3 → NH2NO2 + HNO3. In the case in which HNO3 accumulates in the molten AN, alternate reactions producing NH2NO2 are HNO3 + HNO3 → N2O5 + H2O and subsequently N2O5 + NH4+ → NH2NO2 + H2O. In both scenarios, HNO3 plays the role of a catalyst and the overall reaction can be written as NH4+ + NO3 (AN) → NH2NO2 + H2O. Although the unimolecular decomposition of NH2NO2 is thermodynamically unfavorable, water and bases both promote the decomposition of this molecule to N2O and H2O. Thus AN thermal decomposition in the liquid phase can be summarized as NH4+ + NO3 (AN) → N2O + 2H2O.  相似文献   

16.
An experimental study on the conversion of NO in the NO/N2, NO/O2/N2, NO/C2H4/N2 and NO/C2H4/O2/N2 systems has been carried out using dielectric barrier discharge (DBD) plasmas at atmospheric pressure. In the NO/N2 system, NO decomposition to N2 and O2 is the dominating reaction; NO conversion to NO2 is less significant. O2 produced from NO decomposition was detected by an on-line mass spectrometer. With the increase of NO initial concentration, the concentration of O2 produced decreases at 298 K, but slightly increases at 523 K. In the NO/O2/N2 system, NO is mainly oxidized to NO2, but NO conversion becomes very low at 523 K and over 1.6% of O2. In the NO/C2H4/N2 system, NO is reduced to N2 with about the same NO conversion as that in the NO/N2 system but without NO2 formation. In the NO/C2H4/O2/N2 system, the oxidation of NO to NO2 is dramatically promoted. At 523 K, with the increase of the energy density, NO conversion increases rapidly first, and then almost stabilizes at 93–91% of NO conversion with 61–55% of NO2 selectivity in the energy density range of 317–550 J L−1. It finally decreases gradually at high energy density. A negligible amount of N2O is formed in the above four systems. Of the four systems studied, NO conversion and NO2 selectivity of the NO/C2H4/O2/N2 system are the highest, and NO/O2/C2H4/N2 system has the lowest electrical energy consumption per NO molecule converted.  相似文献   

17.
The kinetic regularities of the thermal decomposition of dinitramide in aqueous solutions of HNO3, in anhydrous acetic acid, and in several other organic solvents were studied. The rate of the decomposition of dinitramide in aqueous HNO3 is determined by the decomposition of mixed anhydride of dinitramide and nitric acid (N4O6) formed in the solution in the reversible reaction. The decomposition of the anhydride is a reason for an increase in the decomposition rates of dinitramide in solutions of HNO3 as compared to those in solutions in H2SO4 and the self-acceleration of the process in concentrated aqueous solutions of dinitramide. The increase in the decomposition rate of nondissociated dinitramide compared to the decomposition rate of the N(NO2)2 anion is explained by a decrease in the order of the N−NO2 bond. The increase in the rate constant of the decomposition of the protonated form of dinitramide compared to the corresponding value for neutral molecules is due to the dehydration mechanism of the reaction. For Part 1, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 41–47, January, 1998.  相似文献   

18.
The thermal decompositions of polycrystalline samples of [Ni(NH3)6](NO3)2 were studied by thermogravimetric analysis with simultaneous gaseous products of the decomposition identified by a quadruple mass spectrometer. Two measurements were made for samples placed in alumina crucibles, heated from 303 K up to 773 K in the flow (80 cm3 min?1) of Ar 6.0 and He 5.0, at a constant heating rate of 10 K min?1. Thermal decomposition process undergoes two main stages. First, the deamination of [Ni(NH3)6](NO3)2 to [Ni(NH3)2](NO3)2 occurs in four steps, and 4NH3 molecules per formula unit are liberated. Then, decomposition of survivor [Ni(NH3)2](NO3)2 undergoes directly to the final decomposition products: NiO1+x, N2, O2, nitrogen oxides and H2O, without the formation of a stable Ni(NO3)2, because of the autocatalytic effect of the formed NiO1+x. Obtained results were compared both with those published by us earlier, by Farhadi and Roostaei-Zaniyani later and also with the results published by Rejitha et al. quite recently. In contradiction to these last ones, in the first and second cases agreement between the results was obtained.  相似文献   

19.
The equilibrium constant for the reaction has been determined between 331 and 480°K using a variable-temperature flowing afterglow. These data give ΔH°(1) = -1.03 ± 0.21 kcal/mol and ΔS°(1) = —4.6 ± 1.0 cal/mol°K. When combined with the known thermochemical values for HBr, Br?, and HNO3, this yields ΔH(NO3?) = -74.81 ± 0.54 kcal/mol and S(NO3?) = 59.4 cal/mol·°K. In addition ΔHn-1,n and ΔSn-1,nfor the gas-phase reactions were determined for n = 2 and 3. The implications of these measurements to gas-phase negative ion chemistry are discussed.  相似文献   

20.
The crystal structure of the title compound, μ‐2‐hydroxy­butane­dioato‐1κ2O4,O4′:2κ3O1,O2,O4‐nitrato‐2κO‐tris­(1,10‐phen­anthroline)‐1κ4N,N′;2κ2N,N′‐dicopper(II) nitrate tetra­hydrate, [Cu2(C4H3O5)(NO3)(C12H8N2)3](NO3)·4H2O, contains an unsymmetrical dinuclear copper complex with Cu(phen)2 and Cu(phen)(NO3) moieties (phen is 1,10‐phenanthroline) bridged by a malate (2‐hydroxy­butane­dioate) ligand, which acts as a double‐bridging and tetra­dentate ligand. As a result of this double‐bridging action, especially the direct coordination of the O atom of one carboxyl­ate group of malate to the two Cu atoms, the Cu⋯Cu distance is only 4.199 (1) Å and the two phen planes are roughly parallel [the shortest inter­planar distance is 3.28 (1) Å], exhibiting an obvious intra­molecular π–π stacking inter­action.  相似文献   

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