Reactivity and transformation routes of surface nitrates in the reaction of NOx reduction by C3H8 over cation-exchanged zeolites

FITRS combined with¹⁵N and¹⁸O isotope substitution and TPD have revealed that nitrates are the most abundant ad-NO_x species on over-exchanged Cu- and Co-ZSM-5 zeolites. the transformation rates of such species under the action of a propane—oxygen mixture were found to be comparable and sufficiently high to afford steady-state catalytic activities. A scheme of the reaction mechanism including C, N-containing intermediates detected in work is suggested.     

Interaction of trimethylsilyl ions with nitrates of the estrane series in the gas phase

The interaction of trimethylsilyl ions with nitrates of the estrane series affords the adducts [M + SiMe₃]⁺, whose fragmentation proceeds through the elimination of the functional groups either along with the trimethylsilyl residue, or in the form of molecules containing no SiMe₃.     

Influence of the temperature and phase state of K,Ca/NO<Subscript>3</Subscript> and K,Mg/NO<Subscript>3</Subscript> binary systems on the vibrational anharmonicity and orientational mobility of the nitrate ion

The absorption spectra of homogeneous and heterophase melts and glasses of the K,Ca/NO₃ and K,Mg/NO₃ systems are studied by IR Fourier spectroscopy. The temperature-phase dependences for the first and second order spectra are analyzed, and the anharmonicity constants for internal vibrations of the nitrate ion are estimated. The influence of finely dispersed Al₂O₃ powder on the structural-dynamic properties of the K,Ca/NO₃ and K,Mg/NO₃ systems is studied. A mechanism for charge transfer in heterophase nitrate glasses is proposed. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 2, pp. 176–181, March–April 2009.     

Role of Intermolecular Interactions in Forming the Vibrational Spectra of Carbohydrate Nitrate Crystals in the Region 1600–1700 cm−1

To elucidate the role of intermolecular interactions in forming the vibrational spectra of the crystals of carbohydrate nitrates in the region 1600–1700 cm^–1, theoretical calculations are performed (in the approximation of an additive model of interatomic interactions with the use of the Green's functions) for the density of vibrational states and the intensity of absorption bands in the IR spectrum of a methyl--D-glucopyranoside tetranitrate molecule in a crystal. It is shown that the splitting of absorption bands in the IR spectral region under consideration relates to the crystal effect.     

The influence of different salting-out agents on the extraction of Ce,Eu, Gd,Tb using tri-n-butyl phosphate

The extraction enthalpies H ^o of Ce, Eu, Gd, Tb nitrates usingTBP in the presence of different salting-out agents in aqueous phase were determined. It was established that the extraction process is the most exothermic in the case of LiNO₃.

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Der Einfluß verschiedener Aussalzmittel auf die Extraktion von Ce, Eu, Gd und Tb mit Tri-n-butylphosphat

Zusammenfassung Es wurden die Extraktionsenthalpien H ^o von Ce-, Eu-, Gd- und Tb-Nitrat unter Verwendung vonTBP in Gegenwart verschiedener Aussalzmittel in wäßriger Phase bestimmt. Es wurde festgestellt, daß der Extraktionsprozeß im Fall von LiNO₃ am meisten exotherm verläuft.

     

Study of the reaction of tungsten carbide in molten alkali metal nitrates. Syntheses of divalent (s and d blocks) metal tungstates

WC is tested as precursor to synthesize metal tungstates by reaction in molten alkali metal nitrates. This constitutes a complex redox system with two reducing agents, W and C, and an oxidizer having several oxidation states. The mass loss due to the evolution of gases reveals the reaction steps. The infrared analyses of the gas phase show what kind of reaction develops according to the temperature. WC produces a water-soluble alkali metal tungstate. The reaction of a mixture of WC and a divalent metal chloride (Mg, Ca, Ba, Ni, Cu, Zn) leads to water-insoluble metal tungstates. As the reactivity of the cations increases in the order Zn, Ni, Cu, the reaction of WC is modified by their presence. The physico-chemical characterizations of the products show that some of them are contaminated either by WC or by metal oxide. Some others are rather pure products. These differences, in relationship with the other analyses, allow to propose first reaction pathways of the tungsten carbide in molten salts.     

Neuuntersuchung der Methode der thermischen Zersetzung zur Auftrennung von Yttererdnitraten in großem Maßstab

Summary The chemical reactions involved were investigated in more detail and methods for treatment of larger quantities were developed. Contrary to former opinions, the hydrolysis of the partially decomposed melt is decisive for the quality of separation. The reaction of the melt with water occurs in two steps, and in both cases distribution coefficientsK of Er up to 4 could be achieved. From 12kg yttrium earth oxide around 8kg were prepared nearly free from Er and the heavierYE.

     

环氧乙烷四氢呋喃共聚醚P（E－CO－T）的研制（Ⅱ）

研究了高ＥＯ含量、高相对分子质量产品的制备方法．采取提高后期反应温度，反应一定时间后再补加催化剂，延长聚合时间等措施，用本体聚合法可制备高ＥＯ含量Ｍｎ≤４０００的二官能度共聚醚；延长聚合时间，用溶液聚合法可制备高ＥＯ含量Ｍｎ＞４０００的二官能度共聚醚；用活性氧化铝吸附可除去高ＥＯ含量粗产品中的酸性催化剂．     

Atmospheric pressure chemical ionization of explosives induced by soft X‐radiation in ion mobility spectrometry: mass spectrometric investigation of the ionization reactions of drift gasses,dopants and alkyl nitrates

A promising replacement for the radioactive sources commonly encountered in ion mobility spectrometers is a miniaturized, energy‐efficient photoionization source that produce the reactant ions via soft X‐radiation (2.8 keV). In order to successfully apply the photoionization source, it is imperative to know the spectrum of reactant ions and the subsequent ionization reactions leading to the detection of analytes. To that end, an ionization chamber based on the photoionization source that reproduces the ionization processes in the ion mobility spectrometer and facilitates efficient transfer of the product ions into a mass spectrometer was developed. Photoionization of pure gasses and gas mixtures containing air, N₂, CO₂ and N₂O and the dopant CH₂Cl₂ is discussed. The main product ions of photoionization are identified and compared with the spectrum of reactant ions formed by radioactive and corona discharge sources on the basis of literature data. The results suggest that photoionization by soft X‐radiation in the negative mode is more selective than the other sources. In air, adduct ions of O₂^– with H₂O and CO₂ were exclusively detected. Traces of CO₂ impact the formation of adduct ions of O₂^– and Cl^– (upon addition of dopant) and are capable of suppressing them almost completely at high CO₂ concentrations. Additionally, the ionization products of four alkyl nitrates (ethylene glycol dinitrate, nitroglycerin, erythritol tetranitrate and pentaerythritol tetranitrate) formed by atmospheric pressure chemical ionization induced by X‐ray photoionization in different gasses (air, N₂ and N₂O) and dopants (CH₂Cl₂, C₂H₅Br and CH₃I) are investigated. The experimental studies are complemented by density functional theory calculations of the most important adduct ions of the alkyl nitrates (M) used for their spectrometric identification. In addition to the adduct ions [M + NO₃]^– and [M + Cl]^–, adduct ions such as [M + N₂O₂]^–, [M + Br]^– and [M + I]^– were detected, and their gas‐phase structures and energetics are investigated by density functional theory calculations. Copyright © 2016 John Wiley & Sons, Ltd.     

Anreicherung schwerer Yttererden aus Magnesiumnitrat-haltigen Lösungen durch basische Fällung mit MgO und fraktionierte Kristallisation der Nitrate in großem Maßstab

Summary Partial basic precipitation by magnesium oxide concentrates the heavy yttrium earths in the precipitate, while yttrium and the lighter earths remain in solution. On fractionating the above solutions by crystallisation of the nitrates, yttrium and the heavy yttrium earths concentrate in the solutions; this method seems better for the treatment of large quantities than the former one. From solutions containing 68.9 kg mixed yttrium earth oxides the heavy ones were concentrated to a great extent in 35.8 kg oxide.