Reaction Of Nitrous Oxide Research Articles

Alkane‐ and areneoxodiazonium ions: experimental results leading to an ab initio theoretical investigation

AbstractAlkaneoxodiazonium ions (R—NNO)+ and (R—O—N2)+, which are closely analogous to alkanediazonium ions (R—N2)+, were detected as reactive intermediates in acid‐catalysed reactions of nitrosohydroxylamines and deamination‐type reactions. The isomers were compared by high‐level MO investigations of the reactions of nitrous oxide with cationic electrophiles H+, CH3+, Me3C+ and PhCH2+. Strongly bonded species are formed in reactions with the powerfully electrophilic H+ and CH3+, and the resulting ions differ considerably in stabilities; less stable species are formed with Me3C+ and PhCH2+ and the complexes so formed have similar stabilities. Two isomers of Ph(N2O)+, analogous to phenyldiazonium ion, PhN2+, are calculated to be stable ions with the end‐N‐bonded isomer being preferred over the O‐bonded ion at the MP4(SDQ)/6–311G(d,p)//MP2(fc)/6–31G(d,p) and G3 levels of theory. Both are non‐planar with the phenyl ring at 90° to the non‐linear N2O residue. Syntheses of salts of Ar(N2O)+ are now planned. Copyright © 2003 John Wiley & Sons, Ltd.

Intramolecular 15N and 18O fractionation in the reaction of N2O with O(1D) and its implications for the stratospheric N2O isotope signature

Atmospheric nitrous oxide (N2O) is enriched in heavy oxygen and nitrogen isotopes relative to its tropospheric sources. This enrichment is traced back to kinetic isotope effects in the two stratospheric N2O sink mechanisms, i.e., photolysis and reaction with O(1D). Most of the previous studies on the cause of isotopic enrichment in N2O have focused on photolysis. Here we present results on the 18O and the position‐resolved 15N kinetic isotope effects in the reaction of nitrous oxide with O(1D) obtained by recently developed mass spectrometric techniques. Just as in the photolysis sink, a heavy isotope enrichment in the residual N2O was found, but of smaller magnitude. However, the fractionation pattern of nitrogen isotopes at the two nonequivalent positions in the molecule is clearly distinct from that in photolytic N2O destruction. The fractionation constant for the terminal nitrogen atom, 15ε1 = k(14N2O)/k(15N14NO) − 1 = (8.87 ± 0.15) %, is larger than for the central nitrogen atom, 15ε2 = k(14N2O)/k(14N15NO) − 1 = (2.22 ± 0.12) % (all errors are 2σ). The fractionation constant for oxygen, 18ε = k(N216O)/k(N218O) − 1 = (12.38 ± 0.14) %, was found to be larger than for nitrogen and amounts to about twice the value from the single previous determination. The larger influence of the O(1D) sink at lower stratospheric altitudes could probably explain the lower ratio of 15ε2/15ε1 (≡η) observed there, which is shown to be only marginally influenced by transport. The published data on stratospheric η values suggest that, if there are no other chemical reactions involved, up to 60% of the overall N2O loss at lower altitudes could be from the reaction with O(1D).

ChemInform Abstract: Reaction of Nitrous Oxide with Cyclopentadienyl Complexes of Cobalt, Rhodium, and Titanium.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Reaction of Nitrous Oxide with Cyclopentadienyl Complexes of Cobalt, Rhodium, and Titanium

The reaction of nitrous oxide with some cyclopentadienyl compounds of cobalt, rhodium, and titanium was studied. The corresponding furans were obtained in low to moderate yields.

Does Reaction of Three-Coordinate Molybdenum(III) with N2O Proceed via the Same Mechanism as with N2? A Theoretical Study

Hybrid density functional (B3LYP) and integrated molecular orbital and molecular mechanics (IMOMM) calculations were performed to elucidate the mechanism of the reaction of nitrous oxide with the MoL3 complex, where L = NH2 and N[(tBu)(3,5-C6H3Me2)], respectively. The first step of the reaction is coordination of N2O to the Mo center of MoL3, leading to the formation of (N2O)MoL3. From this complex, the reaction may proceeds via two distinct mechanisms, mononuclear and dinuclear. The mononuclear mechanism takes place via an N−N bond cleavage transition state and leads to formation of NMo(NH2)3 and free nitric oxide NO, which spontaneously reacts with another Mo(NH2)3 fragment, producing (NO)Mo(NH2)3. The dinuclear mechanism starts by coordination of another MoL3 to (N2O)MoL3, leading to formation of L3Mo(N2O)MoL3, and splits further into two different paths, leading to N−O and N−N cleavage processes, among which the N−O activation is kinetically and thermodynamically more favorable. The experimental observation of the exclusive N−N cleavage is consistent only with the mononuclear mechanism. It was shown that inclusion of steric effects of the bulky amido ligands strongly favors the mononuclear mechanism by destabilizing the dinuclear reaction species much more than mononuclear species. The rate-determining step of the reaction of N2O with bulky MoL3 in the mononuclear mechanism is the N−N bond activation, which takes place with an 11 kcal/mol free energy of activation. Comparing these results with those for the reaction of N2 with MoL3 on one side and with available experiments on another side, we conclude that reactions of N2O and N2 with MoL3 proceed via different mechanisms: nitrous oxide reacts with MoL3 via a mononuclear mechanism, while dinitrogen reacts via a dinuclear mechanism.

A Transient Kinetic Study of the Oscillating N2O Decomposition over Cu--ZSM-5

Isothermal oscillations during the catalytic decomposition of nitrous oxide over copper-exchanged ZSM-5 have been studied at 698 K employing mass spectrometry. Catalysts with a copper exchange level greater than 100% are more active for N2O decomposition and only these samples exhibit sustained oscillations. Two states of the catalysts with different activity toward the formation of N2could be identified. Transient experiments by using step changes in nitrous oxide concentration showed that large amounts of adsorbed species are present on the catalyst surface under working conditions. It is proposed that atomic oxygen and nitrate are formed by reaction of nitrous oxide. The amounts of adspecies change during oscillations and mirror the development of gas-phase concentrations. While gas-phase oxygen had no effect on the observed phenomena, addition of NO and other reducing agents such as H2and CO resulted in disappearance of the oscillations and maintained the catalyst in the more active state. The results suggest that the active species for nitrous oxide decomposition is monovalent copper and that the periodic oxidation and reduction of active sites is responsible for the development of kinetic oscillations.

Ignition of lignite in a fluidized bed

Rate-ratio asymptotic analysis is carried out to elucidate the influence of nitrous oxide on the structure and critical conditions for extinction of nonpremixed methane flames. Steady, axisymmetric, laminar flow of two counterflowing streams toward a stagnation plane is considered. One stream is made up of a mixture of methane and nitrogen. The other stream is a mixture of oxygen, nitrous oxide, and nitrogen. A reduced mechanism of five global steps is employed in the analysis. Chemical reactions are presumed to take place in a thin reaction zone that is established in the vicinity of the stagnation plane. On either side of this thin reaction zone, the flow field is inert. These inert regions are called outer zones. Methane and nitrous oxide are completely consumed in the reaction zone, while oxygen is presumed to leak through the reaction zone. In the reaction zone, chemical reactions are presumed to take place in two layers—the inner layer and the oxidation layer. In the inner layer fuel (methane) is consumed and the intermediate species hydrogen and carbon monoxide are formed. These intermediate species are oxidized in the oxidation layer to water vapor and carbon dioxide. Radicals are produced in the oxidation layer from chain-branching reactions that consume hydrogen. Asymptotic analysis gives the scalar dissipation rate at extinction. Critical conditions for extinction predicted by the analysis agree well with previous experimental data. Nitrous oxide is found to have an inhibiting effect on the flame, promoting extinction. The inhibiting effect is attributed to the competition between the net reaction of nitrous oxide with hydrogen to form water vapor and nitrogen and the chain-branching reaction between oxygen and hydrogen that produces radicals.

Measurement of multioxygen isotopic (δ18O and δ17O) fractionation factors in the stratospheric sink reactions of nitrous oxide

Nitrous oxide is an important component in the Earth's atmosphere with a global budget that shows significant imbalance between known sources and sinks. A recent isotopic analysis of atmospheric nitrous oxide has suggested that back fluxing from the stratosphere could be an important source of N2O to the troposphere. To quantitatively determine the potential magnitude of this process, the relevant isotopic fractionations must be known. We have measured the isotopic fractionation factors associated with the two known stratospheric sink reactions of N2O: photolysis and photooxidation. It is observed that nitrous oxide photolysis produces no fractionation in δ18O and δ17O, while photooxidation produces a small mass‐dependent enrichment in 18O and 17O in the residual N2O.

Kinetic study of the magnesium (1S) + nitrous oxide reaction in the temperature range from 470 to 925 K

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetic study of the magnesium (1S) + nitrous oxide reaction in the temperature range from 470 to 925 KChris Vinckier and Piet ChristiaensCite this: J. Phys. Chem. 1992, 96, 5, 2146–2150Publication Date (Print):March 1, 1992Publication History Published online1 May 2002Published inissue 1 March 1992https://doi.org/10.1021/j100184a024RIGHTS & PERMISSIONSArticle Views15Altmetric-Citations11LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Get e-Alerts

Reactions of 1CH2, Cl and Br in the presence of nitrous oxide

Reaction of nitrous oxide with methylene, chlorine and bromine atoms was attempted at temperatures of up to 300° C, no evidence for the formation of nitrogen was however observed. Some qualitative observations are reported.

Vibrational-state distribution of nitrogen(B3.PI.g) produced from the argon(3P2,0) + nitrous oxide reaction

The N/sub 2/(B/sup 3/II/sub g/) product-state distribution for v' = 0-12 has been analyzed from the fluorescence observed in an Ar(/sup 3/P/sub 2,0/) + N/sub 2/O afterglow. This vibronic distribution shows a non-Boltzmann property, inverted at v' = 4. N/sub 2/(B) was found to be formed via predissociation of the Rydberg state converging into the ground state of N/sub 2/O/sup +/. The golden-rule model and the half-collision model in the collinear configuration are applied to this reaction system to explain the dynamical features. The results show that both Franck-Condon-like effects and final-state interactions are important in the predissociative excitation of N/sub 2/O. Potential curves are proposed for the effective harmonic oscillator and the repulsive states to reproduce the experimental vibronic-state distribution of N/sub 2/(B) and to interpret the predissociation mechanism.

Characterization of copper/alumina catalysts prepared by deposition—precipitation using urea hydrolysis : I. Nitrous Oxide Decomposition and Reaction of Ethanol

Copper—alumina catalysts with a wide range of copper loadings (4 to 34 wt.-%) were prepared by depositing Cu 2+ on suspended γ-alumina through precipitation from a homogeneous solution using urea hydrolysis at 90–95°C. The effect of copper content on the crystallographic phase and BET surface area of the catalysts calcined at 400°C for 24 h was investigated. Catalysts containing ≤16 wt.-% copper did not show any copper containing phase indicating the presence of highly dispersed or amorphous copper species. These catalysts have shown high copper metal areas ranging from 308 to 108 m 2/g-Cu as determined by the reaction of nitrous oxide with copper surfaces at 90°C. While catalysts with low copper content exhibited both dehydration and dehydrogenation activity, those with high copper content showed only dehydrogenation activity at reaction temperatures of 250–300°C. The selectivities for dehydrogenation products were correlated with copper areas of the catalysts.

Reaction of nitrous oxide with a nickel surface

The decomposition of nitrous oxide on nickel powder and on nickel supported on γ-alumina and silica was studied. The reaction proceeds according to the equation N 2O + Ni s = Ni s-O + N 2. Simultaneous measurements of the kinetics and thermal effects of the reaction indicated that the uptake of oxygen in the course of nitrous oxide decomposition proceeds in two stages: (i) fast chemisorption on the Ni surface until the O/Ni s ratio approaches 0.3–0.4 and (ii) nucleation and growth of islands of the surface nickel oxide until a closed layer is obtained. Decomposition of nitrous oxide on nickel supported of γ-alumina and silica proceeds similarly to that on nickel powder.

ChemInform Abstract: EXPERIMENTS CONCERNING PHOSPHORUS CHEMILUMINESCENCE

AbstractDie starke Chemilu‐ mineszenz des Systems PH3/N2O im Sichtbaren wird nach Initiierung durch eine schnelle elektrische Entladung im Druckbereich 18‐666 Torr untersucht.

Experiments concerning phosphorus chemiluminescence

A variety of experimental techniques have been employed in a spectroscopic investigation of the strong visible chemiluminescence from the phosphine–nitrous oxide reaction system. Reaction was initiated by a fast electrical discharge in PH3/N2O mixtures over the pressure range 18–666 Torr. The predominant emission is a true continuum extending from a threshold wavelength at 3300 Å to beyond 1 μm. The results are consistent with the possible existence of a chemically formed (PO)2* exciplex molecule as the source of the visible continuum emission, but another molecular emitter containing only phosphorus and oxygen atoms, such as PO2, cannot be ruled out. Because of the possible use of this reaction system for a tunable, visible laser source, laser cavity tests and absorption and stimulated emission tests were carried out; these gave negative results. The photon yield from 3300 to 9000 Å was determined to vary linearly with pressure; a maximum yield of 8.5×10−3 was reached at the highest pressure investigated of 666 Torr. The broad spectral range of emission and low photon yield indicates that the ratio of stimulated emission to spontaneous emission did not exceed 0.02 at any wavelength shorter than 9000 Å.

Nitric oxide and oxygen reactions with 1-butene over manganese(III) oxide

Reactions of 1-butene with nitric oxide from 623 to 723 K and with oxygen from 433 to 573 K have been studied in a differential flow system over manganese(III) oxide. Nitrous oxide was formed in the reaction of the hydrocarbon with nitric oxide along with products of complete combustion. The apparent activation energies were respectively 69 ± 4, 78 ± 4, and 30 ± 4 kJ mol−1 for nitrogen, carbon dioxide, and nitrous oxide reaction rates. The corresponding pre-exponential factors were 1.72 × 10−1 and 1.16 mol0.5 L−0.5 m2 g−1, and 1.99 × 10−2 mol−0.35 L0.35 m2 g−1. In the reaction with oxygen, apparent activation energies of 183 ± 4, 523 to 503 K, and 88 ± 4 kJ mol−1, 503 to 433 K, were determined with pre-exponential factors 1.74 × 1015 and 2.94 × 105 mol0.3 m−2 g−1. During catalysis the oxide underwent a partial phase change from α to γ in both reactions. Additionally, nitrate species were present on the surface after oxidation with nitric oxide. Kinetic expressions have been derived and mechanisms proposed for both reactions which may occur in emission control systems requiring the removal of NOx and unburned hydrocarbons.

ChemInform Abstract: KINETICS, KINETIC DEUTERIUM ISOTOPE EFFECTS, AND MECHANISM OF NITROUS OXIDE REACTION WITH HYDROGEN ON SUPPORTED PRECIOUS‐METAL CATALYSTS

AbstractDie Reaktion zwischen N2O und H2 läuft an den Trägerkatalysatoren Ru/Al2O3, Rh/Al2O3, Ir/Al2O3 und Pt/Al2O3 über die Grundschritte A und B ab.

Kinetics, kinetic deuterium isotope effects, and mechanism of nitrous oxide reaction with hydrogen on supported precious-metal catalysts

The kinetics and kinetic deuterium isotope effects have been precisely measured for the reaction of nitrous oxide with hydrogen on Ru/Al/sub 2/O/sub 3/, Rh/Al/sub 2/O/sub 3/, Ir/Al/sub 2/O/sub 3/, and Pt/Al/sub 2/O/sub 3/ catalysts. The reaction apparently proceeds through the two following elementary steps: N/sub 2/O + M ..-->.. N/sub 2/ + M=O (reaction 1) and M=O + H/sub 2/ ..-->.. M + H/sub 2/O (reaction 2). In reaction 1, an N/sub 2/O molecule attacks the vacant metal site on the surface (M) to form an N/sub 2/ molecule and an adsorbed oxygen atom (M=O). In reaction 2, the reaction of the surface oxygen atom with an H/sub 2/ molecule takes place to form an H/sub 2/O molecule and the vacant metal site. The activation energy for reaction 1 increases in the order Ru/Al/sub 2/O/sub 3/ Rh/Al/sub 2/O/sub 3/ > Ir/Al/sub 2/O/sub 3/. The preexponential factors of the rate constant for both reactions 1 and 2 do not vary significantly from one catalyst to another, although the value for reaction 1 is aboutmore » 10/sup 4/ times smaller than that for reaction 2. The experimental results have been satisfactorily explained with the transition-state theory coupled with the above-mentioned reaction mechanism.« less

Dissociative charge-transfer reactions of nitrous oxide

The dissociative charge-transfer reactions of N 2O with H 2 + at relative translational energies of 0.6-5.0 keV have been examined by the ion-beam-into-static-gas technique. As the translational energy is altered, there are changes in the relative cross-sections for charge transfer of the various vibronic states participating in the reaction. The total relative reaction cross-section, the production branching ratios, and the ionic fluorescence data are interpreted in terms of reactions involving these particular vibronic states.

Interaction of nitrous oxide with ruthenium (10 [formula omitted]0)

The reactions of nitrous oxide with ruthenium as observed on the Ru(1010) surface occur in two modes. Scission of the ON 2 bond with chemisorption of oxygen and release of molecular nitrogen to the gas phase is one, and breaking of both the ON and NN bonds in ONN with chemisorption of both O and N is the other. Energetic considerations lead to the conclusion that the latter mode is a concerted reaction. Site exclusion by preadsorption of oxygen or carbon monoxide inhibits the reaction, and where sufficient aounts of either of these two adsorbates are present, the activity of the surface can be reduced to zero. N 2O can produce ruthenium oxide on the surface at sufficiently high temperatures, pressures, and contact times.