Catalytic hydrogenation of carbon monoxide over nanostructured perovskite-like gadolinium and strontium ferrites

The catalytic properties of perovskite-like ferrites (A_{n + 1}B_nO_{3n + 1}, where n = 1, 2, 3, …, ∞; A = Gd, Sr; and B = Fe) synthesized via ceramic and sol-gel technology in the hydrogenation of carbon monoxide are studied. The interrelation between catalytic activity, selectivity to olefins and synthetic methods for complex oxide preparation, the number of perovskite layers, crystallite size, composition, and the valence state of iron is established.     

Rheological properties of ethylene-propylene-diene elastomers

The processing of rubbers comprises a combination of complicated processes which realization almost always requires knowledge of their rheological behavior. The goal of the present work is to describe the rheological behavior of the EPDM vulcanizates via rotational rheometry. The effect of the cross-linking density and plasticizer content on the rheological behavior of the EPDM vulcanizates is described. The viscoelastic characteristics of the samples are defined from the frequency dependences of elasticity modulus G' and loss modulus G".     

Synthesis of 2-alkoxy-4-[<Emphasis Type="Italic">N</Emphasis>-(alkyl,cycloalkyl, aryl)imino]phenyl <Emphasis Type="Italic">m</Emphasis>-carboranecarboxylates

Previously unknown m-carborane-containing azomethines (Schiff bases) were synthesized by the reaction of esters derived from vanillin or vanillal and m-carboranecarboxylic acid with primary amines in absolute methanol.     

Hypergene and Technogenic Formation of Minerals Depending on the Sulfur Content of Tailings in the Tailing Dump of the Krasnorechensk Concentrating Mill (Dalnegorsk District,Primorsky Krai)

Using Selektor program for simulation of chemical equilibria, physicochemical modeling of the EhpH parameters of forming solutions, composition of minerals crystallizing therefrom, and stability fields of these minerals was performed in dependence to the amount of flotation and sulfide sulfur in tailings exposed to water in systems that are open and closed to the atmosphere. This problem is considered for the first time for the given region.     

Revisiting ether-derivatized imidazolium-based ionic liquids

A series of ether-derivatized imidazolium halides have been prepared and characterized. Contrary to literature reports, they are all crystalline solids and have melting points well above room temperature (50-100 degrees C). Single crystals of the imidazolium salts, obtained in situ by slow cooling from their molten state to room temperature, were analyzed by X-ray crystallography, revealing various anion-cation interactions in the solid state. Exchange of the halides with [Tf(2)N]- yielded room temperature ionic liquids with viscosities that are comparable to related 1-alkyl-3-methylimidazolium ionic liquids. Density functional theory combined with IR spectroscopy has been used to analyze the role of functionalization of the imidazolium side chain on the formation of the molecular and supramolecular structure of the compounds and its possible impact on their physical properties.     

A cobalt(ii) acetate complex with 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-1H-indole-2,3-dione 3-thiosemicarbazone: synthesis and structure

A complex of Co^II with 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-1H-indole-2,3-dione 3-thiosemicarbazone was obtained and identified by X-ray diffraction, IR and Raman spectroscopy, and quantum chemical calculations. The characteristic C=S frequencies in the IR spectra of the thiosemicarbazones were refined. The data obtained from different methods were compared, which allows more accurate spectroscopic studies of related structures.     

Photocatalytic properties and hydration of perovskite-type layered titanates A2Ln2Ti3O10 (A = Li, Na, K; Ln = La, Nd)

Layered perovskite-type oxides A₂Ln₂Ti₃O₁₀ (A = Li, Na, K; Ln = La, Nd) prepared by solid-phase synthesis and their hydrated forms were characterized by the methods of TGA, XRD, and by UV-Vis spectroscopy. Photocatalytic activity of A₂Ln₂Ti₃O₁₀ oxides in reaction of hydrogen evolution from aqueous alcoholic suspensions irradiated by UV-light was studied. It was shown that the ability to intercalation of water into interlayer space essentially affects the rate of photoinduced hydrogen evolution and is a determining factor leading to a high photocatalytic activity.     

Transition state theory thermal rate constants and RRKM‐based branching ratios for the N(2D) + CH4 reaction based on multi‐sState and multi‐reference Ab Initio calculations of interest for the titan's chemistry

Multireference single and double configuration interaction (MRCI) calculations including Davidson (+Q) or Pople (+P) corrections have been conducted in this work for the reactants, products, and extrema of the doublet ground state potential energy surface involved in the N( ² D) + CH₄ reaction. Such highly correlated ab initio calculations are then compared with previous PMP4, CCSD(T), W1, and DFT/B3LYP studies. Large relative differences are observed in particular for the transition state in the entrance channel resolving the disagreement between previous ab initio calculations. We confirm the existence of a small but positive potential barrier (3.86 ± 0.84 kJ mol^?1 (MR‐AQCC) and 3.89 kJ mol^?1 (MRCI+P)) in the entrance channel of the title reaction. The correlation is seen to change significantly the energetic position of the two minima and five saddle points of this system together with the dissociation channels but not their relative order. The influence of the electronic correlation into the energetic of the system is clearly demonstrated by the thermal rate constant evaluation and it temperature dependance by means of the transition state theory. Indeed, only MRCI values are able to reproduce the experimental rate constant of the title reaction and its behavior with temperature. Similarly, product branching ratios, evaluated by means of unimolecular RRKM theory, confirm the NH production of Umemoto et al., whereas previous works based on less accurate ab initio calculations failed. We confirm the previous findings that the N( ² D) + CH₄ reaction proceeds via an insertion–dissociation mechanism and that the dominant product channels are CH₂NH + H and CH₃ + NH. © 2012 Wiley Periodicals, Inc.     

Synthesis,IR/Raman,and quantum‐chemical structural analysis of new octathiotetraphosphetane ammonium salts

New octathiotetraphosphetane ammonium salts are obtained based on the reaction of white phosphorus (P₄) and elemental sulfur with aliphatic mercaptans in the presence of amines (morpholine , methylmorpholine, pyrrolidine, and N,N‐dimethylbenzylamine). Both the salts and novel Cu(I) chloride complex with the pyperidinium salt of octathiotetraphosphetane are characterized by IR/Raman spectroscopy in combination with DFT methods. The comparative spectral analysis reveals clear spectral features, characteristic for a P₄S₈⁴⁻ anion, which are present in IR and Raman spectra of all the compounds obtained. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 22:24–30, 2011; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20651     

Functionally Substituted Isothiazole- and Isoxazolecarboxamides

Russian Journal of Organic Chemistry - Convenient synthetic approaches to functionally substituted 5-phenyl-1,2-oxazole-3-carboxamides and 4,5-dichloro-1,2-thiazole-3-carboxamides were developed on...