French-Ukrainian Journal of Chemistry
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A difluorenyl-carbo-cyclohexadiene: prospective chromophore for two-photon absorption
Get PDFFor the purpose of outlining structure-property relationships for two-photon absorption (2PA), a "s-locked" carbo-cyclohexadiene with two fluorenyl substituents has been envisaged for comparison with previously studied aromatic carbo-benzene and non-aromatic carbo-quinoid congeners. A representative where the C10-π-conjugated fluorenyl moieties are also connected by a C8-π-insulating 3,6‐dimethoxy‐3,6‐bis(trifluoromethyl)octa‐1,4,7‐triyn-1,8-diyl edge has thus been synthesized in four steps from known C8F triyne and C10 triynyldial, through a [8F+10] cyclization process. In spite of a relatively strong absorbance (e = 84 800 L.mol-1.cm-1 at 634 nm), the non-vanishing green fluorescence (at 533 nm) of the chromophore should allow measurements of the 2PA cross section by both the TPEF and Z-scan methods
Behaviour of Solid Oxide Fuel Cell Materials in Technological Environments
Get PDFThe YSZ–NiO ceramics for SOFC anodes and MAX-phases of Ti-Al-C systems for interconnects have been investigated. Based on the tests of YSZ–NiO specimens preconditioned by one-time reduction or by redox cycling at 600 or 800 °C, a certain mode of the material treatment was established which provides its improved physicomechanical properties. The oxidation behaviour of MAX-phases has been investigated at 600 °C in air. It was found that the intense initial oxidation of hot-pressed Ti3AlC2-based material can be eliminated by a certain mode of pre-oxidation. The oxidation resistance of the material can be significantly improved by niobium addition
Reaction of 1-aminoisoindole with methyl 4-chloro-3-oxobutanoate
Get PDFCondensation of bifunctional 1-aminoisoindole with bis-electrophilic methyl 4-chloro-3-oxobutanoate undergoes regioselectively to afford 2-(chloromethyl)-2-hydroxy-2,6-dihydropyrimido[2,1-a]isoindol-4(3H)-one. The structure of the reaction product was unambiguously established by HMQC and HMBC heteronuclear correlations. The functionalization of the synthesized compound by reactions with a series of aliphatic amines was carried out
Investigation of the structure, phase composition, and electrochemical characteristics of hydrogen-sorbing intermetallics of the La–Мg–Ni system obtained by the sintering method
Get PDFThe crystal structure, phase composition, and electrochemical properties of the materials obtained by sintering of (LaNi3+Mg+Ni) powder mixture in the temperature range 640–1020°С have been investigated. Experimental results show that, at temperatures of ≤850°С, the sintered multiphase material, whose major phases are phases with PuNi3-type structure (LaMg2Ni9 and LaNi3) and CaCu5-type structure (LaNi5), is formed. With increase in temperature, the number of phases in the sintered material decreases to a single major phase LaNi5, and the content of the LaMg2Ni9 phase practically does not change. It has been established that increase in sintering temperature deteriorates the activation of the electrode materials and slows down the hydrogen absorption process. At the same time, the maximum discharge capacity and cyclic stability of electrodes increase
Energy Effective Membrane-less Technology for High Pressure Hydrogen Electro-chemical Generation
Get PDFWater electrolysis process for hydrogen generation is widely used in various branches of industry. But it has disadvantages like important energy consumption and utilization of separate membranes, which limit the generated gases pressure.This article describes the hydrogen and oxygen generation technology excluding the separating ion-exchange membranes and providing high gases pressure due to applying the variable valence metal chemically active electrodes as well as due to separating in time and space the electrolytic processes of water decomposition for gases liberation.The electrolyzer based on this technology surpasses all of the known analogues by the level of technical decisions, simplicity of mounting and servicing, reliability and safety
Heteroassociates of Pinacianol Cation in Aqueous Solutions: Formation and their Interaction with Organic Multiply Charged Anions
Get PDFThe formation of heterogeneous associates has been studied between the cation of the cyanine dye as pinacyanol chloride (PNC) and multiplies charged anions arsenazo (AR II) or humus acids (HA) in aqueous solutions. The accompanying spectral changes have been analyzed. The equilibrium constants of association (Kas) were determined, and logKas values were equal in the range 1.73-3.09 for associates PNC with HA. The effect of humus acids on PNC -AR II causes to destruction of the associate and the competition of the anions of HA with AR II is observed
Mechanical alloys Mg-Me (Me: Ti, Fe, Ni, Al) & Mg-Me1-Me2(Ме1:Al, Me2: Ti, Fe, Ni) with low resistance and improved kinetics of hydrogenation/dehydrogenation for hydrogen storage applications
Get PDFChanges in MgH2 decomposition kinetics were investigated in dependence on complex doping of MgH2 by Al, Ti, Ni,and Fe. Reactive mechanochemical alloying method (RMA) was applied in the temperature descending regime. It was found that addition of Al+Ni+Ti, Al+Ti, Fe+Ti (see below) and Al+Fe elements combinations led to a lower thermal stability and, consequently, to a lowering of the temperature of hydrogen desorption onset. Whereas desorption began at temperature of 320 °C from the pure MgH2, the aditions of Al, Ni, Ti and Fe lowered the start of the desorption down to 250°C (at hydrogen pressure 0.1 MPa in the reactor). Very fast desorption kineticsprecize at 300 0C and PH 2= 0.1 MPa were observed for Mg+Me mixture in comparison with the pure Mg. Sorption capacity of investigated mechanically-alloyed composites varied from 5 to 6.5 wt. % H2. The tested materials showed a high potential as hydrogen storage alloys especially for stationary application
Chemical composition of subcritical water extraction extract of Tribulus Terrestris
Get PDFSubcritical water extraction of Tribulus terrestris leaves and fruits was performed at 100 ºC and 60 atm for 30 min. Chemical composition of volatile extracts was investigated. A simple lactone compound Loliolide (23,82%) was main components associated with 26 identified molecules which are mostly oxygenated compounds
Lipid peroxidation during chronic inflammation
Get PDFTo keep needed level of peroxide lipid oxidation is necessary for the normal functioning of physiological systems. It is supported by the balance of anti-and prooxidant systems. The positive influence of lipid peroxidation processes in the organism is manifested by the restoration of the composition and maintenance of the properties of biological membranes, participation in energy processes, cell division, synthesis of biologically active substances. It has been established that the inflammatory process is accompanied by changes in lipid metabolism and the intensity of peroxide oxidation
Study of impact factors and the mechanism of gypsum binder hydration process in the presence of nanomodifiers
No full textThis article represents the results of the research of nanomodification of mineral binders involving structure formation mechanisms and gypsum binder hydration process, and thus, affecting various properties. Experiments proved that during growth, crystals partly penetrate into each other and form a three-dimensional network permeating and incorporating the entire gypsum stone into a whole body, which promotes structuring of calcium sulfate matrix and improvement in gypsum compressive strength up to 30%. Chemical functionalization of the surface of carbon nanotubes promotes a reduced sedimentation effect, allows for a more uniform nanostructure dispergation throughout the modified material volume and provides chemical interaction between the substance matrix and nanotubes