- Nitrogen Quadrupole Coupling Measurements on ON-NO2 Using the Flygare-Balle Pulsed-Beam Spectrometer
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High-resolution measurements of the 101 00, 212 11, 202 01, 211 0, 312 13, and 413 14 transitions in the ON-NO2 complex were made by using a pulsed-beam, Fourier transform microwave spectrometer.Nearly all hyperfine structure components were resolved on observed transitions except for the 202 01 group.The quadrupole coupling tensors in the principal axis system were determined for both nitrogen atoms.The nitrogen quadrupole coupling components for the NO group are eQqaa = -1.7766 +/- 0.0037 MHz and eQqbb = 0.0585 +/- 0.0021 MHz.For the NO2 group eQqaa = -0.5260 +/- 0.0035 MHz and eQqbb = -4.1941 +/- 0.0018 MHz.The rotational constants obtained are A = 12412 +/- 22 MHz, B = 4226.530 +/- 0.012 MHz, and C = 3152.966 +/- 0.012 MHz.Rotational transition frequencies and estimates of spin-rotation interaction strengths are given.The observed quadrupole coupling strengths are substantially different from those observed for the free NO and NO2 molecules.
- Kukolich, Stephen G.
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- Selective oxidations by nitrosating agents: Part 2: Oxidations of alcohols and ketones over solid acid catalysts
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The reactivity of a nitrosating agent (N2O3) on oxidations of alcohols and the methyl group of acetophenone were tested. Active electrophylic surface nitrosonium ions (NO+) was detected on H 2SO4/SiO2 catalysts by Raman spectroscopy, suggesting a surface ionic mechanism of oxidation in agreement with the one proposed in acid aqueous solutions. Alcohols are selectively oxidized to ketones and aldehydes in high yield, useful for synthetic applications, at 25 °C in 1,2-dichlorethane and using commercial sulfonated styrene divinyl benzene resins (Amberlyst 15) as catalysts. In addition, nitrous acid ester has been observed as intermediates according to an ionic mechanism by surface NO+. Under the same reaction conditions, acetophenone is selectively oxidized to benzoyl cyanide in high yield and selectivity. The comparison with oxidation carried out in aqueous solution of HNO2, where benzoyl formic acid was obtained, suggests that the differences in the final products are likely due to the specific stabilizing effect of each solvent. Moreover, the reactivity of the intermediates isolated in aqueous systems implies that α-nitroso-acetophenone is a probable reaction intermediate also in aprotic heterogeneous systems.
- Marziano,Ronchin,Tortato,Ronchin,Vavasori
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- Anhydrous Dinitrogen Trioxide Solutions for Br?nsted Acid Free Nitrous Acid Chemistry
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Dinitrogen trioxide, N2O3, is readily prepared and stabilized in high concentrations in dry organic solvents at normal working temperatures. These conditions allow for facile acid and water free nitrosation and nitration reactions fo
- Rosadiuk, Kristopher A.,Bohle, D. Scott
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- Isolable Adducts of Tertiary Amines and Dinitrogen Trioxide
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Anhydrous dinitrogen trioxide, N2O3, dissolved in toluene or dichloromethane rapidly forms stable adducts with tertiary amines such triethyl-, tribenzyl-, or trihexyl-amine. With DABCO, 1,4-diazabicyclo[2.2.2]octane it forms a free flowing orange solid. The analytical and spectroscopic data for the DABCO adduct indicate a formula of DABCO(N2O3)2 which has been characterized by IR, Raman, and UV/Vis spectroscopy. The R3N-N2O3 adducts are hydrolytically sensitive oils or solids which rapidly react quantitatively with thiols to give RSNO. The reactivity of the amine adducts is variable, and the products include amine N-oxides, ammonium nitrites, and ammonium nitrates depending upon the adduct, conditions, and substrate. Density functional theory, B3LYP/aug-cc-pvtz, has been used to compare the predicted structures and spectroscopic data for mono and bis adducts. Geometry optimization of the R3N N2O3 adduct gives a weakly bound Lewis acid/base adduct with the amine nitrogen closest to the nitrosyl N with a strongly tilted planar ONNO2 unit.
- Rosadiuk, Kristopher A.,Scott Bohle
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p. 4543 - 4549
(2018/10/31)
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- Etching silicon with HF-HNO3-H2SO4/H 2O mixtures- unprecedented formation of trifluorosilane, hexafluorodisiloxane, and Si-F surface groups
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The etching behaviour of sulfuric-acid-containing HF-HNO3 solutions towards crystalline silicon surfaces has been studied over a wide range of H2SO4 concentrations. For mixtures with low sulfuric acid concentration, NO2/N2O4, N 2O3, NO and N2O have been detected by means of FTIR spectroscopy. Increasing concentrations of nitric acid lead to high etching rates and to an enhanced formation of NO2/N2O 4. Different products were observed for the etching of silicon with sulfuric-acid-rich mixtures [c(H2SO4) > 13 mol L -1]. Trifluorosilane and hexafluorodisiloxane were identified by FTIR spectroscopy as additional reaction products. In contrast to the commonly accepted wet chemical etching mechanism, the formation of trifluorosilane is not accompanied by the formation of molecular hydrogen (according to Raman spectroscopy). Thermodynamic calculations and direct reactions of F 3SiH with the etching solution support an intermediate oxidation of trifluorosilane and the formation of hexafluorodisiloxane. The etched silicon surfaces were investigated by diffuse reflection FTIR and X-ray photoelectron spectroscopy (XPS). Surprisingly, no SiH terminations were observed after etching in sulfuric-acid-rich mixtures. Instead, a fluorine-terminated surface was found.
- Lippold, Marcus,Boehme, Uwe,Gondek, Christoph,Kronstein, Martin,Patzig-Klein, Sebastian,Weser, Martin,Kroke, Edwin
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p. 5714 - 5721
(2013/02/25)
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- DeNOx of exhaust gas from lean-burn engines through reversible adsorption of N2O3 in alkali metal cation exchanged faujasite-type zeolites
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NO and NO2 associated as the asymmetric N2O3 conformer compete with water molecules for coordination with sodium cations of the sodium-water clusters in supercages of the Na-Y zeolite. This reactive NO(x) adsorption is rev
- Sultana, Asima,Loenders, Raf,Monticelli, Orietta,Kirschhock, Christine,Jacobs, Pierre A.,Martens, Johan A.
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p. 2934 - 2937
(2007/10/03)
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- Stabilization of the Primary Products of O(1D) Reactions with CO, CO2, CH4, and Other Hydrocarbons in Cryogenic Matrices
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Broad-band UV-visible irradiation of argon matrices containing 2percent N2O and 10percent of either CO, CO2, methane or ethane resulted in the formation of CO2, CO3, CH3OH, or CH3CH2OH as the dominant photoproducts of O(1D) reactions, as observed by FTIR
- Parnis, J. Mark,Hoover, Larry E.,Fridgen, Travis D.,Lafleur, Rick D.
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p. 10708 - 10711
(2007/10/02)
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- Photodissociation of NO2 Adsorbed on LiF(001)
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The photochemistry of NO2 physisorbed on single-crystal LiF(001) at 100 K has been studied at λ1 = 248 nm.The adsorbate was examined by polarized FTIR in both the presence and absence of λ1 radiation.In the absence of UV irradiation the adlayer is composed of dimeric (NO2)2.In the presence of UV, FTIR shows that some N2O3 is formed.Photodissociations(PDIS) giving both NO(g) and molecular NO2(g) were the predominant mechanisms as determined by time-of-flight mass spectrometry (TOF-MS) and resonantly enhanced multiphoton ioniziation (REMPI).The main objective of this work was the characterization of the photoproduct, NO, internal state distribution by 1 + 1 REMPI.Vibrational levels from v = 0 to 9 were probed with rotational resolution using a tunable laser, λ2.The rotational distributions for each vibrational level could be described by one Boltzmann temperature.The spin-orbit states of NO(g) were equally populated in all vibrational levels.The lambda doublet states, Π(A') and Π(A ), were equally populated.The principal observation was that the vibrational distribution in NO(g) was inverted and bimodal with a peak in v = 0 and a second substantial peak in v = 3-4, qualitatively resembling but qualitatively different from that for photolysis of NO2(g).Time delays between the two lasers were used to probe the translational energy of the NO(g) photofragment in specified states of internal excitation.The transational energy distributions were invariant over all vibrational levels, except v = 0 for which much slower fragments were observed.This complete determination of the energy distribution in the degrees of freedom of the NO(g) from photodissociation of adsorbate has implications for the identity of the photolyzing species and the dynamics of photodissociation.Two mechanisms for photoformation of NO2(g) were found: one at low coverages and one at higher coverages, the former giving peak translational energies ca. 1.2 kcal/mol and the latter 0.4 kcal/mol.
- Dixon-Warren, St. J.,Jackson, R. C.,Polanyi, J. C.,Rieley, H.,Shapter, J. G.,Weiss, H.
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p. 10983 - 10994
(2007/10/02)
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- Reaction of certain nitrogen oxides with iron(III) porphyrin μ-oxo complexes
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The nitrogen oxides NO, N2O4, and N2O3 and the μ-oxo complexes [Fe(TPP)]2O and [Fe(OEP)]2O, where TPP and OEP are the dianions of meso-tetraphenylporphine and octaethylporphyrin, respectively, were reacted in toluene in the absence of O2. [Fe(TPP)]2O was reacted with the nitrogen oxides in dimethylacetamide (DMA). All of the reactions were followed by changes in the electronic spectra. The NO reaction with [Fe(TPP)]2O in toluene yielded a solid product, Fe(TPP)(NO)(NO2)·C7H8·2H 2O. The N2O4 and the N2O3 reactions in toluene produced Fe(TPP)NO3 and Fe(OEP)NO3, while in DMA these reactions gave an equilibrium amount of Fe(TPP)(DMA)x+, the solvated complex.
- Settin, Marc F.,Fanning, James C.
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p. 1431 - 1435
(2008/10/08)
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- A Study of the Gas-Phase Reaction of NO2 with O3 by Matrix Isolation Infrared Spectroscopy
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The observed products of the NO2 + O3 reaction are N2O3 and N2O4.The presence of N2O3 as a product indicates that NO is formed in secondary reactions and subsequently reacts with NO2 to produce N2O3.In the experiments where ozone was allowed to deposit at a rapid rate (0.27 mmol/h), infrared absorptions attributable to N2O5 and NO were observed.We attribute the production of N2O5 to the formation of the symmetrical NO3 radical.Our data indicate that both the symmetrical and asymmetrical NO3 radicals are intermediates in the reaction of NO2 + O3.An explanation for the presence of NO in nighttime chemistry is given.Attempts to isolate symmetrical NO3 were unsuccessful.
- Morris, V. R.,Bhatia, S. C.,Hall, John H.
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p. 3359 - 3361
(2007/10/02)
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- Disproportionation of Nitric Oxide at High Pressure
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A facile pressure-induced disproportionation of nitric oxide occurs at 176 K and 1.5 GPa.The reaction products are N2O4, N2O, and a small, variable amount of N2O3 as identified by infrared, Raman, and visible absorption spectroscopies.No free NO, N2O2, or NO2 is observed after warming the sample to room temperature.The N2O4 product subsequently photolyzes to form N2O3 and NO2+NO3-, and evidence for the nitrite form of N2O4 is reported.The N2O product is stable, once formed, to 14.0 GPa.
- Agnew, S. F.,Swanson, B. I.,Jones, L. H.,Mills, R. L.
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p. 1678 - 1682
(2007/10/02)
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- Plasma Chemistry of Air. I. The Reaction of Nitrogen and Oxygen in a Microwave Discharge at Low Pressures
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In a 2.45 GHz microwave-sustained discharge the reaction of nitrogen and oxygen at 1 - 10 Torr was characterized by nitric oxide formation and a bright emission which was analyzed for excited states of N2(C), N2(+), O, O(+), and NO(γ).Mass spectrometric analysis showed that a significant amount of NO was present in the plasma gas, but NO2 was formed usually when the plasma gas was passed through a cold trap at temperatures below 175 K.The NO2/NO ratio in the product increased with decreasing trap temperature and N2/O2 composition.At 77 K N2O3 was formed in the trap, but it decomposed to NO and NO2 upon warming the condensate to 298 K.By using mixtures with N2/O2 = O.25 conversions up to 10percent of the N2 input to NO and NO2 were calculated from (1) pressure measurements of the NO and NO2 evolved on warming the condensate to 298 K and (2) titration of aqueous solutions of the condensate formed after reacting it with air and water or a known amount of NaOH solution. - Keywords: Plasma chemistry / Microwave discharge / Nitrogen-oxygen reaction / Air
- Venugopalan, M.,Rajaei-Rizi, A.
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- A Matrix-Isolation-Infrared Spectroscopic Study of the Reactions of Nitric Oxide with Oxygen and Ozone
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The oxidation of nitric oxide to NO2 has been studied by trapping the products of the gas-phase reactions of nitric oxide with excess oxygen and ozone in argon matrices at 10 K.The subsequent transitient species were identified and characterized by their infrared spectra.The primary products of the NO + O2 reactions were NO2, N2O3(A), N2O3(B), N2O4, and peroxy nitrate (OONO).The primary products of the NO + O3 reactions were NO2 and peroxy NO3 with the higher nitric oxides (N2O3, N2O4) formed in low concentrations relative to the NO + O2 reactions.Isotopic oxygen and ozone were employed to identify the infrared absorption frequency of peroxy nitrate.On the basis of our observations, reaction mechanisms are proposed for the oxidation of NO to NO2.
- Bhatia, Subhash C.,Hall, John H.
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p. 3255 - 3259
(2007/10/02)
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