Temperature dependence of the reaction NO + NO3 → 2NO2

The flash photolysis-visible absorption technique has been used to measure rate constants for the reaction NO + NO₃ → 2NO₂ (1) over the temperature range 224–328 K. The temperature dependence of the rate constant is given by the expression k₁(T) = (1.59 ± 0.32) × 10⁻¹¹exp(122/T) cm³ molecule⁻¹ s⁻¹ where the stated uncertainties refer to the ± 2σ limits from both random and systematic errors.     

Separation of15N by chemical exchange in NO, NO2−HNO3 system under pressure

The basic isotopic exchange reaction is responsible for the separation of¹⁵N in the Nitrox system that between gaseous nitrogen oxides and aqueous nitric acid with a single stage separation factor α=1.055 for 10M nitric acid, at 25°C and atmospheric pressure takes place. In order to know what happens in¹⁵N separation at higher pressure, when the isotopic transport between two phases is improved, a stainless steel laboratory experimental plant with a 1000 mm long × 18 mm i.d. column, packed with triangular wire springs 1.8×1.8×0.2 mm², was utilised. At 1.5 atm (absolute), and 2.36 ml·cm⁻²·min⁻¹ flow rate HETP was 7% smaller than at atmospheric pressure and 1.5 times smaller flow rate. HETP at 3.14 ml·cm⁻²·min⁻¹ flow rate and 1.8 atm is practically equal with that obtained at atmospheric pressure and 2 times smaller flow rate. The operation of the¹⁵N separation plant at 1.8 atm (absolute), instead of atmospheric pressure, will permit doubling of the 10M nitric acid flow rate and of¹⁵N production of the given column.     

Revised thermochemistry of gaseous ammonium nitrate, NH₄NO₃(g)

In an earlier paper (Hildenbrand, D. L., Lau, K. H., and Chandra, D. J. Phys. Chem. B 2010, 114, 330.), we detected the presence of NH?NO?(g) in the vapor over the solid nitrate and evaluated its partial pressure along with those of HNO? and NH?. The molecular constants of the gaseous nitrate were estimated in the absence of experimental values in an attempt to derive its enthalpies of sublimation and formation. After publication, we became aware of the sought molecular data, evaluated primarily from high-level theoretical calculations, and revised the analysis to yield Δ(f)H???°(NH?NO?(g)) = ?61.8 ± 5 kcal mol?1.     

Chinese Journal of POLYMER SCIENCE VOLUME 15, NO. 1-4, 1997 CONTENTS

1 .Polymerisatfon,radieal,co叮dinatfon and ring叩euingVi叮IRadlealPolymer场ation灿tiatedwithCerielonandEthylN,N一Diethy】dithioearba江LylAcet助e SystemXU Sho可”。and QIUK公。夕。a。(254)Graft Polymerization of Acrylalnide onto Homopolymer ofs一Met勿l一5一Hexen-2,令Dione加tiated勿Ceric fon么月通O几匆bo,z月滩OTo仰aod QIU而。,。a。(50)E反ets ofExtern以D~ouActiveCenterDistribu幼onofsupPortedziegler~NattaCatalystFANZh‘乒a呼M.Ca,ela Sacch‘aod Paolo Locatel八(217)CoPol扣mer汤at…     

Thermochemistry of ammonium nitrate, NH₄NO₃, in the gas phase

Hildenbrand and co-workers have shown recently that the vapor above solid ammonium nitrate includes molecules of NH?NO?, not only NH? and HNO? as previously believed. Their measurements led to thermochemical values that imply an enthalpy change of D??? = 98 ± 9 kJ mol?1 for the gas-phase dissociation of ammonium nitrate into NH? and HNO?. Using updated spectroscopic information for the partition function leads to the revised value of D??? = 78 ± 21 kJ mol?1 (accompanying paper in this journal, Hildenbrand, D. L., Lau, K. H., and Chandra, D. J. Phys. Chem. B 2010, DOI: 10.1021/jp105773q). In contrast, high-level ab initio calculations, detailed in the present report, predict a dissociation enthalpy half as large as the original result, 50 ± 3 kJ mol?1. These are frozen-core CCSD(T) calculations extrapolated to the limiting basis set aug-cc-pV∞Z using an anharmonic vibrational partition function and a variational treatment of the NH? rotor. The corresponding enthalpy of formation is Δ(f)H???°(NH?NO?,g) = ?230.6 ± 3 kJ mol?1. The origin of the disagreement with experiment remains unexplained.     

Li,K∥F,NO3 and Li,K∥Cl,NO3 three-component reciprocal systems

Phase equilibria in Li,K∥F,NO₃ and Li,K∥Cl,NO₃ three-component reciprocal systems were studied by differential scanning calorimetry (DSC). Eutectic compositions (mol %) in the Li,K∥F,NO₃ system were determined to be as follows: 5.0 LiF, 10.0 KF, and 85.0 KNO₃ with T _m = 281°C and 48.5 KNO₃, 44.0 LiNO₃, and 7.5 LiF with T _m = 105°C. Eutectic compositions (mol %) in the Li,K∥Cl,NO₃ system were determined to be as follows: 10.0 LiCl, 32.1 KCl, and 57.9 LiNO₃ with T _m = 147°C and 44.5 KNO₃, 45.0 LiNO₃, and 10.5 KCl with T _m = 97°C.     

Selective Catalytic Reduction of NO with Methane

The removal of nitrogen oxides from exhaust gases has attracted great attention in recent years, and many approaches have been developed depending on the application. Methane. the main component of natural gas, has great potential as a NO reductant. In this paper, a number of catalysts previous reported for this catalytic reduction of NO have been reviewed, including a direct comparison of the relative activities and effective factors of the catalysts. Reaction mechanisnls have also been explored preliminarily.     

Chinese Journal of POLYMER SCIENCE VOLUME 14 NO. 1-4, 1996

CONTENTSPolymerization,10n1C,graft,block and ring openingStu勿on the Cationic Polymerization ofl,3一entadiene Initiated场AIC13/Alkyl HalideS”terns 尸丑万G物蕊。9, Llu几ali。,刀通IHa。。即邵dC‘N“承ng......................……(91)Iduenees of叭/a ter-soluble Catioule Monomers on the PolymerisationR石te in the Inverse Emulsion HOUS红‘a。叭d HAR佩加a ......................……,.....................……(183)Graft CoPolymerization of Vi叮1 Monomers onto Starehl址tiatedby升ansitio…     

Damage of aromatic amino acids by the atmospheric free radical oxidant NO3˙ in the presence of NO2˙, N2O4, O3 and O2

Analysis of the products formed in the reaction of NO(3)˙ with the N- and C-protected aromatic amino acids 1-5, which was performed under conditions that simulate exposure of biosurfaces to environmental pollutants, revealed insight how this important atmospheric free-radical oxidant can cause irreversible damage. In general, NO(3)˙ induced electron transfer at the aromatic ring is the exclusive initial pathway in a multi-step sequence, which ultimately leads to nitroaromatic compounds. In the reaction of NO(3)˙ with tryptophan 5 tricyclic products 12 and 13 are formed through an intramolecular, oxidative cyclization involving the amide moiety. In addition to this, strong indication for formation of N-nitrosamides was obtained, which likely result from reaction with N(2)O(4) through an independent non-radical pathway.     

Theoretical Study of Rg·NO (Rg=He,Ne, Ar and Kr) Complexes

Rg·NO (Rg=He, Ne, Ar and Kr) complexes were studied using ab initio calculations. The neutral Rg·NO complex geometry and vibrational frequencies were calculated with the cc-pVDZ basis set at the CCSD(T) level of theory. The calculations show that the geometry of the Rg·NO complexes is a skewed T-shape with the Rg atom on the oxygen side of the NO molecule, and that the RgNO bond angle increases with mass. The dissociation energies (DE) and ionization energies (IE) of the neutral Rg·NO complexes, and the dissociation energies of Rg·NO+ ionic complexes were calculated using Gaussian-2 (G2) methods and a high accuracy energy model. The ionization energies of the neutral Rg·NO complexes range from 9.265 eV for He·NO to 9.132 eV for Kr·NO and the dissociation energies of Rg·NO+ range from 0.017 eV for He·NO+ to 0.156 eV for Kr·NO+, in line with the expectation based on the increasing polarizability of the Rg atom.     

Influence of NO on the Reduction of NO2 with CO over Pt/SiO2 in the Presence of O2

Reduction of NO2 with CO in the presence of NO and excess oxygen, a model mixture for flue gas, over a 0.1% Pt/SiO2 catalyst was studied. The related reaction mechanisms, such as oxidation of CO and NO, were discussed. It was found that there was a narrow temperature window （180-190 ℃） for the reduction of NO2 by CO. When the temperature was lower than the lower limit of the window, the reduction hardly occurred, while when the temperature was higher than the upper limit of the window, the direct oxidation of CO by O2 occurred and thereby NO2 could not be effectively reduced by CO. The presence of NO shifted the window to higher temperatures owing to the inhibition effect of NO on the activation of O2 on Pt, which made it possible to reduce NO2 by CO in flue gas.     

NO3^—,NO2^—同时测定的研究进展

综述了近年来农业、环境科学和食品科学中NO_3~-、NO_2~-同时测定方法的研究进展。     

Radiation-Thermal Decomposition of NO2–NO Mixtures in a 60Co γ-Radiation Field

The effect of nitrogen monoxide (up to 60 wt %) on the radiation-thermal decomposition of a dissociating mixture based on N₂O₄ in a ⁶⁰Co -radiation field was studied over the temperature range 200–300° at a pressure of 2 MPa. A comparison of the experimental results with data calculated using an additive mathematical model of radiolysis and data obtained in previous studies on processes in an n,-radiation field led to the conclusion that the role of intermolecular energy-transfer processes is insignificant. The currently available mathematical model adequately describes the radiolysis of nitrogen oxides over wide temperature and pressure ranges.     

Structure,synthesis, and thermal properties of trans-[Ru(NO)(NH3)4(SO4)]NO3·H2O

In treatment of trans-[Ru(NO)(NH₃)₄(OH)]Cl₂ with concentrated sulfuric acid on heating trans-[Ru(NO)(NH₃)₄(SO₄)](HSO₄)·H₂O (I) is obtained with a yield close to quantitative. In the interaction of the saturated solution of I with a saturated NaNO₃ solution a trans-[Ru(NO)(NH₃)₄(SO₄)]NO₃·H₂O (II) precipitate forms whose structure is determined by single crystal XRD: space group P2₁2₁2₁, a = 6.8406(3) Å, b = 12.6581(5) Å, c = 13.3291(5) Å. A monodentately coordinated sulfate ion is in the trans-position to the nitroso group. Compound II is characterized by IR spectroscopy, powder XRD, and diffuse reflectance spectroscopy. The process of its thermolysis is studied; by differential scanning calorimetry the thermal effect of the dehydration reaction occurring on heating to 120°C (ΔH = 58.9 ± 1.5 kJ/mol) is estimated. The final product of the thermolysis of II is a mixture of Ru and RuO₂.     

负载Pt,Pd催化剂上NO—TPD和NO催化还原性能

负载Ｐｔ、Ｐｄ催化剂上ＮＯ－ＴＰＤ和ＮＯ催化还原性能１）钟依均（浙江师范大学化学系金华３２１００４）罗孟飞周碧袁贤鑫（杭州大学催化研究所杭州３１００２８）关键词负载Ｐｔ、Ｐｄ催化剂ＮＯ－ＴＰＤＣＯ－ＮＯ反应分类号Ｏ６４３．３２氮氧化物（ＮＯｘ）污染是...     

Calibration of NO sensors for in-vivo voltammetry: laboratory synthesis of NO and the use of UV–visible spectroscopy for determining stock concentrations

The increasing scientific interest in nitric oxide (NO) necessitates the development of novel and simple methods of synthesising NO on a laboratory scale. In this study we have refined and developed a method of NO synthesis, using the neutral Griess reagent, which is inexpensive, simple to perform, and provides a reliable method of generating NO gas for in-vivo sensor calibration. The concentration of the generated NO stock solution was determined using UV–visible spectroscopy to be 0.28±0.01 mmol L^–1. The level of NO₂^– contaminant, also determined using spectroscopy, was found to be 0.67±0.21 mmol L^–1. However, this is not sufficient to cause any considerable increase in oxidation current when the NO stock solution is used for electrochemical sensor calibration over physiologically relevant concentrations; the NO sensitivity of bare Pt-disk electrodes operating at +900 mV (vs. SCE) was 1.08 nA mol^–1 L, while that for NO₂^– was 5.9×10^–3 nA mol^–1 L. The stability of the NO stock solution was also monitored for up to 2 h after synthesis and 30 min was found to be the time limit within which calibrations should be performed.     

Synthesis and NO production inhibition of novel Mannich base derivatives of irisolidone

Five new C-8 Mannich base derivatives of irisolidone 2a-2e were synthesized and their nitric oxide（NO）production inhibitory activity was evaluated.Compounds 2a,2b,2c and 2e displayed stronger activities in vitro than the parent compound irisolidone.     

NO,NO_2性质的演示装置

NO,NO_2性质的演示装置必须显示出: ①NO不溶于水, ②NO遇氧很易生成红棕色的NO_2, ③NO_2很易溶于水。④NO_2溶于水后显酸性。根据这些要求设计了上图的演示装置。甲为圆底烧瓶带有三孔橡皮塞,其中一孔插长玻璃管,玻管一端直至瓶底,另一端伸入乙瓶,也伸至瓶底;另二孔插入两根短的弯玻管,再套以橡皮管与启普发生器丙、丁相连。乙瓶为与甲瓶同容积的平底烧瓶,带有二孔橡皮塞,其中一孔即插由甲瓶来的玻管如前所述,另一孔插一短的弯玻管3。丙、丁均为启普发生器,在此处用作储气瓶。(收集气体时可先将整个发生器充满了水,然后将气体从发生器出气嘴处压入,水即进入顶上漏斗中。)     

Synthesis, structures, and thermolysis of new heterometallic cobalt, nickel, and copper complexes with the [Ru(NO)(NO2)4(OH)]2− anion as a ligand

Heterometallic complexes with pyridine-N-oxide (PyO), Ru(NO)(NO₂)₄(OH)Ni(PyO)₂(H₂O)] · CH₃COCH₃ (I), [{Ru(NO)(NO₂)₂(μ-NO₂)₂(μ-OH)Co}₂(μ-PyO)] · H₂O · CH₃COCH (II), and [Ru(NO)(NO₂)₄(OH)Cu(PyO)₂ (III), are isolated in the reactions of Na₂[Ru(NO)(NO₂)₄(OH)] with nitrates of the corresponding metals in the presence of the organic ligand. The compounds synthesized are characterized by IR spectra, thermal analysis, and X-ray diffraction analysis. Depending on the M²⁺ cation, the ruthenium cation is coordinated through the bidentate (III, Cu²⁺) or tridentate (I, Ni²⁺ and II, CO₂₊) mode involving the bridging OH group and one or two NO₂ groups. The thermal decomposition of complex II results in the formation of a Co_0.5Ru_0.5 solid solution, which is thermodynamically stable under the decomposition conditions. The thermolysis of complexes I and III in a hydrogen atmosphere leads to the formation of metastable solid solutions.     

Interaction of NO with nanosized Ru-, Pd-, and Pt-Doped SnO2: electron paramagnetic resonance, Mössbauer, and electrical investigation

The mechanism of NO interaction with nanosized Ru(Pd,Pt)-doped SnO(2) was studied by electron paramagnetic resonance, M?ssbauer, and electric resistance measurements. Three steps were proposed for the reaction between the semiconductor oxide and the gaseous component: (i) the formation of bielectronic oxygen vacancies (V(o)) in SnO(2); (ii) their single-ionization (V(o)(*)) with injection of electrons into the SnO(2) conduction band; (iii) the subsequent transfer of electrons from V(o)(*) to [Ru(Pd,Pt)](4+). The last process induces the formation of further oxygen vacancies which reduce the transition metal centers to lower oxidation states; the redox processes is enhanced and the electrical resistance in transition metal-doped SnO(2) is stronger modified with respect to the undoped material.