French-Ukrainian Journal of Chemistry
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Effect of size factor on the Ruddlesden-Popper single-slab compounds structure features
Get PDFCharacter of influence of the strontium atoms replacement by smaller atoms of calcium on structure features of the Ruddlesden-Popper (Sr,Ca)LaScO4 (A2BO4) single-slab compoundis established. Structure of phase with a maximum degree of replacementhas determined by the Rietveld method. It is shown that such type of substitution increases a degree of AO9 interblock polyhedra deformation, mutual inclination of the BO6 octahedra and a decrease of A - О interblock bond. Presence of structure changes is the precondition for regulation of structural-dependent features of the materials on the base of scandates alkaline-earth and rare earth metals
The quantitative determination of Perphenazine in tablets by the spectrophotometric method as its sulfoxide obtained with diperoxyazelaic acid
Get PDFThe oxidative derivatization method using diperoxyazelaic acid for the indirect spectrophotometric determination of Perphenazine dihydrochloride is presented. Diperoxyazelaic acid is introduced as a derivatizing agent for Perphenazine, yielding sulfoxides. This reaction product was successfully employed for the spectrophotometric determination of Perphenazine dihydrochloride. The UV spectroscopic detection of sulfoxide has been proven to be the more robust and selective. The method developed allowed determination of Perphenazine dihydrochloride in the concentration range of 1–40 µg/mL. The limits of quantification (LOQ=10S) is 3.3 µg·ml-1. A new spectrophotometric method has been developed, and the possibility of the quantitative determination of Perphenazine dihydrochloride in Perphenazine Tablets has been demonstrated. The present method is precise, accurate and other inactive excipients of the drug do not interfere. RSD = 2.00%; δ=( -µ) 100%/µ = – 0.85 %)
Room-Temperature Synthesis of the TiC, ZrC, HfC, VC, NbC and TaC Powder Monocarbides
Get PDFThe nanoscaled (up to 30 nm) TiC, ZrC, HfC, VC, NbC and TaC monocarbides with NaCl-type structure have been synthesized from the elemental metals and the carbon nanotubes (CNTs) by mechanical alloying in a high energy planetary ball mill in an argon atmosphere. The powders obtained were examined by X-ray diffraction method. It is shown that mechanical alloying is accompanied by a decrease in the lattice parameters of MeC carbides formed and by a decrease of the total number of atoms in their crystal structure, i.e. by an increase of structural vacancies in the materials obtained. On the whole, monocarbides obtained can be arranged by the simplicity of their formation in a ball mill as: HfC -> ZrC -> TiC -> TaC -> NbC -> VC
Influence of fluorides on phase relations in the molten systems MI2O-Р2О5 Mn2O3/MIIO, МI – Li, Na, K; MII – Ni, Co
Get PDFAddition of alkaline fluorides to molten phosphates with a composition MI2O-Р2О5-Mn2O3 and MI2O-Р2О5-MIIO (МI – Li, Na, K) gradually changes the solubility of polyvalent metals oxides and shifts the crystallization areas in the corresponding melts. The results obtained are based on solubility curves found for Mn2O3, СоО and NiO in the fluxes of MI2O-Р2О5 -MF and MI2O-Р2О5 -MF (where МI – Li, Na, K) and X-Ray diffraction, IR spectroscopy and thermal analysis. The presence of 10 and 20 % mass of fluorides provides molten polyphosphates depolymerization and yields pyro- Li2MnP2O7, K2CoP2O7, Na2CoP2O7and orthophosphates Na2Mn3(P2O7)2, NaMnPO4, NaNiPO4 single crystals growth
Recognition and Binding of Aliphatic Dicarboxylic Acids C4 – C10 by Diiminocalix[4]arene
Get PDFHost-Guest complexation of 5,17-bis-(N-tolyliminomethyl)-25,27-dipropoxycalix[4]arenewithaliphatic dicarboxylicacidsC4 – C10 hasbeenstudiedin water-organic solution by the RP HPLC and molecular modeling methods. The stability constants (log KA =2.56– 3.05) of the supramolecular complexes are depended on structure, pKa and log Pvalues of the acids. The complexation is determined by the hydrogen bonds of the COOH group of the dicarboxylic acids with nitrogen atoms at the upper rim or oxygen atoms at the lower rim of the calixarene
Studies of the Association of Dyes with Surfactants in Aqueous Solutions: Spectrophotometry and Computer Simulation
Get PDFThe association of cationic dye (pinacyanol, PC) with anionic dyes (ethyleosin, EE, or rhodamine 200 C, R200C), and also the interaction “dye+surfactant” has been investigated in aqueous solutions by visible spectroscopy and computer simulation. Cetylpyridinium bromide (CPB), sodium dodecylsulfate (SDS) and triton X-100 (TX) were used as cationic, anionic and non-ionic surfactants respectively. The formation of “dye+surfactant” associates takes place at low dye concentrations (≥10‑6 M) and concentrations of surfactant, which are much smaller than the critical micelle concentrations (CMC). In contrast, similar concentrations (10‑6 – 10‑4 M) of small cations of tetramethylammonium or tetraethylammonium have no noticeable effect on the absorption spectra of the dye in the “dye+tetraalkylammonium salt” systems; it indicates the absence of formation of new compound between the dye and salt. The standard enthalpy of formation of “dye+dye” or “dye+surfactant” associates has been determined by AM1 and PM3 semiempirical methods. The computer simulation confirms that the formation of these associates is energetically beneficial
Selecting a k-ε turbulence model for investigating n-decane combustion in a diesel engine combustion chamber
Get PDFThe results of a comparative numerical simulation of combustion and formation of toxic substances in a diesel engine combustion chamber are given. Experimental findings were used to identify the mathematical models. The impact of the standard, RNG and realizable k-ε turbulence models on the accuracy of numerical simulation of combustion and the formation of toxic substances was studied. The realizable k-ε turbulence model was shown to provide a closer agreement of computational and experimental data during simulation of the diesel engine process when turbulent flows are described
The state of lipid exchange and thrombotic link of hemostasis in patients with chronic non-specific inflammatory diseases of genitals
Get PDFIt has been stated that changes of lipid exchange and increasing of lipid peroxidation are accompanied by the inflammatory process, which show the increase of proatherogenic blood characteristics. In patients with chronic non-specific inflammatory diseases of genitals disorders of phagocytosis mechanisms, increasing of autointoxication and reaction of hypersensitivity of immediate type are revealed after full blood count index. On the basis of analyses results one can conclude that the increase of atherogenic properties of blood plasma in patients with chronic non-specific inflammatory diseases of genitals took place in accordance with vascular endothelium damage. The article is the first to show the effectiveness of complex treatment of different atherosclerotic pathogenesis links by means of correction of proatherogenic lipid fractions and antioxidative complexes
Investigation of Hydrogen Production by using Zinc Coated Platinum Electrode in Phosphate Solutions
Get PDFIn this study, the hydrogen gas producing was investigated at 298 K with zinc coated platinum (Pt-Zn) electrode in 0.1 M NaH2PO4 solution (pH=12.3). Electrolysis, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques were used for the production of hydrogen gas. Scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray fluorescence (XRF) were used for the surface analysis of the electrodes. A practical electrocatalytic experiment was designed to examine of hydrogen production by using a Zn plated Pt electrode and the efficiency of the hydrogen gas increased by 66.66% on the surface of the zinc coated platinum electrode
Ring closing metathesis strategies to isoxazole containing thiadiazepines
Get PDFCyclic sulfamides are attractive molecules with potential application in medical chemistry. It is known that thiadiazepine-containing derivatives demonstrate promising value in the development of protease inhibitors such as HIV protease, serine protease and metaloprotease. We demonstrate here a comfortable synthetic sequence to symmetric thiadiazepines containing isoxazole substitutents. The structure of the obtained substances was confirmed by 1H, 13C NMR spectroscopy