10544-72-6Relevant academic research and scientific papers
Capture of nitrogen dioxide and conversion to nitric acid in a porous metal–organic framework
Li, Jiangnan,Han, Xue,Zhang, Xinran,Sheveleva, Alena M.,Cheng, Yongqiang,Tuna, Floriana,McInnes, Eric J. L.,McCormick McPherson, Laura J.,Teat, Simon J.,Daemen, Luke L.,Ramirez-Cuesta, Anibal J.,Schr?der, Martin,Yang, Sihai
, p. 1085 - 1090 (2019)
Air pollution by nitrogen oxides, NOx, is a major problem, and new capture and abatement technologies are urgently required. Here, we report a metal–organic framework (Manchester Framework Material 520 (MFM-520)) that can efficiently confine dimers of NO2, which results in a high adsorption capacity of 4.2 mmol g–1 (298 K, 0.01 bar) with full reversibility and no loss of capacity over 125 cycles. Treatment of NO2?MFM-520 with water in air leads to a quantitative conversion of the captured NO2 into HNO3, an important feedstock for fertilizer production, and fully regenerates MFM-520. The confinement of N2O4 inside nanopores was established at a molecular level, and the dynamic breakthrough experiments using both dry and humid NO2 gas streams verify the excellent stability and selectivity of MFM-520 and confirm its potential for precious-metal-free deNOx technologies.
Interaction of copper with dinitrogen tetroxide in 1-butyl-3-methylimidazolium-based ionic liquids
Morozov,Deeva,Glazunova,Troyanov,Guseinov,Kustov
, p. 4430 - 4434 (2017)
Ionic liquids that are stable toward oxidation and nitration and are based on the 1-n-butyl-3-methylimidazolium cation (BMIm+) can be used as solvents and reaction media for copper dissolution in liquid dinitrogen tetraoxide N2O4. The ionic liquid not only favors the dissociation of N2O4 into NO+ and NO3?, but also takes part in the formation of different crystalline products. Thus, NO[BF4], NO[Cu(NO3)3] and (BMIm)2[Cu2(CF3COO)6] were prepared using (BMIm)A, A? = [BF4]?, (CF3SO2)2N?, CF3COO?, respectively. The formation of a certain product is determined by the nature of the anion A? and the relative solubility of the reaction products in the ionic liquid. Crystals of NO[BF4] were also prepared directly from a mixture of N2O4 and BMImBF4. According to XRD single-crystal structure analysis, the structure of NO[BF4] consists of tetrahedral [BF4]? anions and nitrosonium NO+ cations; the formation of these ions prove the heterolytic dissociation of N2O4 dissolved in the ionic liquid. The crystal structure of the earlier unknown binuclear copper trifluoroacetate (BMIm)2[Cu2(CF3COO)6] were determined by X-ray diffraction. The peculiarity of this dimer compared to the majority of known dimeric copper(ii) carboxylates is the unusually long Cu?Cu distance (3.15 ?), with Cu(ii) ions demonstrating an atypical coordination of a distorted trigonal bipyramid formed by five O atoms of five trifluoroacetate groups.
Nitropyrene Photoprobes: Making Them, and What Are They Good for?
Espinoza, Eli M.,Xia, Bing,Darabedian, Narek,Larsen, Jillian M.,Nu?ez, Vicente,Bao, Duoduo,Mac, Jenny T.,Botero, Fabian,Wurch, Michelle,Zhou, Feimeng,Vullev, Valentine I.
, p. 343 - 356 (2016)
Pyrene derivatives are among the most widely used organic fluorescent photoprobes. Many of them are photosensitizers for hole injection. Pyrenes, however, are mostly UV absorbers, limiting their utility for photonic applications. Nitration of pyrene shifts its absorption to the visible region. Conversely, nitration of pyrene that is already derivatized for covalent labeling, produces mixtures of isomers that are challenging to separate. We present a robust procedure for attaining isomerically pure nitropyrenes. NMR analysis provides unequivocal assignments of the regioisomers and of the structures of the disubstituted nitropyrenes. The added substituents negligibly affect the electronic properties of the nitropyrenes. Photoexcited nitropyrenes undergo efficient triplet formation, making them an attractive choice for triplet sensitizers and photooxidants. Hence, facile and reliable preparation of disubstituted nitropyrenes provides venues for exploring their electronic and photonic utility.
Explosive Thermal Decomposition Mechanism of RDX
Botcher, Tod R.,Wight, Charles A.
, p. 5441 - 5444 (1994)
Thin films of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) have been subjected to transient pyrolysis using a pulsed CO2 laser in order to determine details of the thermal decomposition mechanism under conditions that simulate a thermal explosion.The first step, scission of an N-N bond, leads to formation of N2O4.The product is trapped in the solid film by rapid quenching to 77 K following the pyrolysis pulse and subsequently detected by transmission FTIR spectroscopy of the film.Product yield measurements show that 1.9 +/- 0.2 RDX molecules are destroyed for every N2O4 molecule detected in the films.Crossover experiments conducted on isotopically labeled samples containing both unlabeled and fully labeled RDX-(15)N6 show that the N2O4 product consists of a statistical mixture of (14,14)N2O4, (14,15)N2O4, and (15,15)N2O4 isotopomers.These results show that both halves of the dimer arise from separate RDX parent molecules and the explosive decomposition of RDX involves loss of only a single NO2 molecule.
Low-Temperature Trapping of Intermediates in the Reaction of NO? with O2
Mahmoudi, Leila,Kissner, Reinhard,Koppenol, Willem H.
, p. 4846 - 4851 (2017)
The autoxidation of NO? was studied in glass-like matrices of 2-methylbutane at 110 K and in a 8:3 v/v mixture of 2,2-dimethylbutane and n-pentane (rigisolve) at 80-90 K, by letting gaseous NO? diffuse into these solvents that were saturated with O2. In 2-methyllbutane, we observed a red compound. However, in rigisolve at 85-90 K, a bright yellow color appears that turns red when the sample is warmed by 10-20 K. The new yellow compound is a precursor of the red one and also diamagnetic. The UV-vis spectrum of the yellow compound contains a band which resembles that present in ONOO-. Because the red and yellow intermediates are not paramagnetic, we postulate that ON-O-O? is in close contact with NO?, or with another ON-O-O?. Diffusion of gaseous O2 into rigisolve saturated with NO? does not produce a color; however, a weak EPR signal (g = 2.010) is observed. This signal most likely indicates the presence of ONOO?. These findings complement our earlier observation of a red color at low temperatures and the presence of ONOO? in the gas phase (Galliker, B.; Kissner, R.; Nauser, T.; Koppenol, W. H. Chem. Eur. J. 2009, 15, 6161-6168), and they indicate that the termolecular autoxidation of nitrogen monoxide proceeds via the intermediate ONOO? and not via N2O2
Falloff Curve and Secific Rate Constants for the Reaction NO2+NO2N2O4
Borrell, Peter,Cobos, C. J.,Luther, K.
, p. 4377 - 4384 (1988)
The rate of association of NO2 to N2O4 was measured in N2 at pressures from 1 to 207 bar.This way the reaction was observed in a large section of its falloff range.The relaxation of NO2/N2O4 mixtures was followed after laser flash photolysis of N2O4 at 248 nm.From the results the falloff curve was constructed, which gives the high- and low-pressure rate constants at 298 K (in cm3 molecule-1 s-1): kassinfinite=(8.3+/-1.0)*10-13 and kass0=(1.4+/-0.2)*10-33.Earlier measurements, believed to be in the low-pressure regime, have not been free from falloff effects.The low value of kinfinite was analyzed with the statistic adiabatic chanell model, and specific rate constants, k(E,J), were calculated.They increase very steeply with energy just above the reaction treshold and go through maxima at low excess energies.These unusual effects are analyzed theoretically and the strong contributions are pointed out of the low-frequency vibrations which disappear during the dissociation of N2O4.
Highly efficient reversible adsorption of NO2 in imidazole sulfonate room temperature ionic liquids
Yuan, Gang,Zhang, Feng,Geng, Jiao,Wu, You-Ting
, p. 39572 - 39575 (2014)
The highly efficient reversible adsorption of NO2 in room-temperature ionic liquids is reported for the first time, making a platform for promising applications.
Reactive species generated during wet chemical etching of silicon in HF/HNO3 mixtures
Steinert, Marco,Acker, Joerg,Krause, Matthias,Oswald, Steifen,Wetzig, Klaus
, p. 11377 - 11382 (2006)
The role of intermediate species generated during wet chemical etching of silicon in a HF-rich HF/HNO3 mixture was studied by spectroscopic and analytical methods at 1°C. The intermediate N2O3 was identified by its cobalt blue color and the characteristic features in its UV-vis and Raman spectra. Furthermore, a complex N(III) species (3NO +·NO3-) denoted as [N4O 62+] is observed in these solutions. The time-dependent decay of the N(III) intermediates, mainly by their oxidation at the liquid-air interface, serves as a precondition for the study of the etch rate as function of the intermediate concentration measured by Raman spectroscopy. From a linear relationship between etch rate and [N4O62+] concentration, NO+ is considered to be a reactive species in the rate-limiting step. This step is attributed to the oxidation of permanent existing Si-H bonds at the silicon surface by the reactive NO+ species. N2O3 serves as a reservoir for the generation of NO+ leading to a complete coverage of the silicon surface with reactive species at high intermediate concentrations. As long as this condition is valid (plateau region), the etch rate is constant and yields a smooth silicon surface upon completion of the etching. If the N2O3 concentration is insufficient to ensure a coverage of the Si surface by NO +, the etch rate decreases linearly with the N2O 3 concentration and results in a roughening of the etched silicon surface (slope region).
Observation of paramagnetic Raman optical activity of nitrogen dioxide
Sebestik, Jaroslav,Bour, Petr
, p. 9236 - 9239,4 (2014)
Raman optical activity (ROA) detects the intensity difference between right and left circularly polarized scattered light, and thus brings about enhanced information about the molecules under investigation. The difference is quite small and the technique is mostly constrained to the condensed phase. For NO2 in the presence of a static magnetic field, however, the ROA signal with high ROA/Raman intensity ratio was observed. The signal is so strong owing to molecular paramagnetism and a pre-resonance signal enhancement. The spectral shape was explained on the basis of the Fermi golden rule and rotational wave functions expanded to a spherical top basis. The results indicate that the technique can be immediately used to obtain information about molecular properties, such as polarizability components. It also has a potential to detect other paramagnetic gases and discriminate among them. Paramagnetic gases: Paramagnetic Raman optical activity of nitrogen dioxide was observed for the first time and explained on the basis of angular momentum theory (see picture). The technique provides enhanced information about molecular properties, and the results suggest that the technique can be immediately used for discrimination and analysis of similar paramagnetic gases.
Infrared spectra and UHF SCF calculations of HF complexes with NO, (NO)2, and NO2
Davis, Steven R.,Andrews, Lester,Trindle, Carl O.
, p. 6027 - 6033 (1987)
HF complexes with nitric oxide and nitrogen dioxide were prepared in argon matrices and studied using IR spectroscopy and unrestricted Hartree-Fock SCF calculations.The results indicate the formation of three different complexes NO--HF, ONNO--HF, and ONO--HF, in which the hydrogen atom of HF is bound to an oxygen atom of the base in each complex.Perturbations in the N-O stretching base submolecule modes were observed in each complex and all were blue shifted with respect to the free base.From the calculations, the unpaired electron was found to be contained in a ? antibonding orbital which is in the plane of the NO- HF and ONO-HF complexes.
