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European chemical bulletinVol. 7., No.11-12. (2018.)

Tartalom

Classical and advanced chemical sciences

  • S. S. Chine ,
    C. S. Patil ,
    R. P. Pawar :

    An efficient protocol was developed for the synthesis of octahydroquinazolinone derivatives in presence of silty clay-containing soil in solvent free conditions under microwave irradiation. The isolated products were characterized by FTIR, 1HNMR and 13C NMR spectroscopy. The catalyst was characterized by wet chemical analysis, SEM, EDS, XRD and IR spectroscopy

    Keywords: Octahydroquinazolinones; microwave-assisted synthesis; multicomponent synthesis; heterogeneous silt catalyst

  • Rama Koteshwar Rao ,
    Shravankumar Kankala :

    Synthesis of 3-amino-1-(5-nitro-1H-indol-2-yl)-5,10-dioxo-5,10-dihydro-1H-pyrazolo[1,2-b]phthalazine-2-carbonitriles by a one-pot green and an eco-friendly reaction of phthalic acid, hydrazine hydrate, indole-3-carboxaldehydes and malononitrile/ethyl cyanoacetate in the presence of Et3N as catalyst and Glycerol mediated at 100-105 oC for 45-60 min. This one-pot reaction proceeded in a short time with good yields and the desired products obtained without using column purifications.

    Keywords: Eco-friendly synthesis; One-pot reaction; pyrazolo[1,2-b]phthalazine; glycerol; triethylamine catalyst

  • Manojkumar U. Chopade ,
    Anil U. Chopade ,
    Santosh V. Padghan :

    Nickel acetylacetonate (Ni(acac)2) as a catalyst was tested in Knoevenagel condensation of benzaldehyde with ethyl cyanoacetate in DMSO to provide α-cyano ethyl cinnamate. The substituted benzaldehydes and 3-methylbutyraldehyde gave similar reaction and the corresponding products were obtained in good yields (78-92%) under clean and straightforward condition.

    Keywords: Knoevenagel condensation, Ni(acetylacetonate)2; benzaldehydes; ethyl cyanoacetate

  • A. A. Agababova ,
    N. Kh. Alchujyan ,
    A. M. Hakobyan ,
    A. G. Gevorkyan ,
    V. H. Barsegyan :

    Acute, inflammatory processes contribute to the fact that conventionally pathogenic and pathogenic microorganisms colonize the mucous membranes of the small intestine and form biofilms, can become a source of bacterial toxin, which, when the epithelial layer breaks, penetrates to the lymphatic and blood systems, contributing to the formation of sepsis. The barrier function of the epithelium is critical in the development of inflammatory bowel diseases, while normal functioning requires a constant balance between reactivity and tolerance to microorganisms of the intestinal lumen. Increased permeability of the intestinal mucosa is the main risk factor for the spread of bacteria. Epithelium, being an essential element of tissue barriers, provides selective transport for the movement of ions and macromolecules, and also creates an obstacle for their penetration into the underlying tissues. Control of the permeability of the epithelial layer is carried out by the apical intercellular complex - tight contacts, which comprise proteins of the claudine family. Intestinal flora affects the sensory, motor and immune functions of the intestine, and also interacts with higher nervous centers. Immunosuppressive processes are one of the main causes of destabilization of the barrier function, intestine, and brain.

    Keywords: Nonspecific ulcerative colitis, sodium dextran sulphate, gastrointestinal tract, probiotic, zeolite, lipid peroxidation, microbiota, intestinal –cerebral axis, inflammation

Materials and environmental chemistry

  • T. Marsagishvili ,
    G. Tatishvili ,
    N. Ananiashvili ,
    J. Metreveli ,
    M. Gachechiladze ,
    E. Tskhakaia ,
    M. Machavariani ,
    N. Giorgadze ,
    Z. Samkharadze :

    We obtained carbon composite materials with desired mechanical characteristics, electrical conductivity, magnetic properties, which are widely used in the production of rubbers, cables, sorption materials from various secondary raw materials like wastes of agricultural production (sawdust, fruit bones, coal industry wastes, etc.) with using a new thermochemical method. The composition of the obtained materials was carried out with scanning electron microscopy (SEM); Surface and porosity of the obtained materials were measured by use of instrument Gemini VII. Electrochemical Cu–C coatings were obtained with the use of carbon nanomaterials and tribological properties of the obtained coatings were investigated. The nanocarbon particles with large specific surface area and high porosity could also be used in composition electrocoating (CEC). The optimal concentration of carbon nanomaterials when CECs have best tribological properties has been determined.

    Keywords: nanocarbon, composition coating, tribological properties, electrodeposition, friction coefficient, secondary raw material

  • N. G. Barbakadze ,
    V. G. Tsitsishvili ,
    T. V. Korkia, ,
    Z. G. Amiridze ,
    N. V. Jalabadze ,
    R.V. Chedia :

    Powdered graphite foil wastes (pGFW) were successfully used for the synthesis of graphene oxide (GO) and reduced graphene oxide (rGO). The remaining graphite foil pieces (wastes) are expanded graphites and their chemical oxidation to GO or to obtain graphene can be conducted using known methods. A fraction with a particle size of 140 μm was obtained by wet and dry grinding. The EDX analysis showed that the powder consists of carbon and oxygen only. The paper presents results obtained in pGF oxidation using low-temperature (0°C; KMnO4–NaNO3–H2SO4) and relatively high-temperature (50°C; KMnO4–H2SO4) modes. In case of low-temperature mode oxidation of pGFW the C/O ratio (at.%) is 61:38. In case of their reduction with ascorbic acid the C/O ratio is 81:19. The method of synthesis of GO and its separation from the reaction mixture were partially corrected. Sulfuric acid and ions (K+, Na+, and Mn+2) can be removed using 5-fold decanting (2 times H2O, 3 times 5% HCl solution). A 5 % solution of HCl precipitates GO-flakes in 7–10 min and, thus, the process of removing the main impurities is accelerated. From decanted solutions, GO was reduced to the rGO with ascorbic acid at 80°C. By the high-temperature treatment of rGO received from graphite foil wastes graphene is obtained with a defective structure.

    Keywords: graphite foil wastes, Hummers method, graphene oxide, reduced graphene oxide

  • Habibat Faith Chahul ,
    Elijah Maji ,
    Rufus Shaato :

    Understanding the mechanism of corrosion of steel in acidic environments along with the accompanying quest for corrosion inhibitors that are nontoxic to the environment is of significant industrial concern. This work sets to investigate the corrosion of mild steel in 1.0 M solution of HCl in the presence of Euphobia tirucalli gums (ET) using weight loss and linear polarization measurements. The study was carried out within the inhibitor concentration range of 0.2-1.0 g L-1 and at the temperature range of 303 - 333 K. From the results obtained, it was observed that ET gums inhibited the dissolution of mild steel in the acid medium. Thermodynamic parameters obtained from the studies revealed the corrosion inhibition process to be spontaneous, exothermic and physisorptive. The adsorption of ET gums on the steel surface aligned well with the Langmuir, Freundlich and Temkin isotherm models. Linear polarization results revealed that ET functioned as a mixed-type inhibitor by inhibiting both the cathodic and anodic reactions on the mild steel surface.

    Keywords: Euphobia tirucalli, adsorption isotherm, activation energy, corrosion inhibition

Theoretical and computational chemistry

  • J. I. Bagdavadze ,
    Z. N. Tsikaridze ,
    K. Z. Ukleba :

    Metal borides and carbides, TiB2/TiC and ZrB2/ZrC are widely used nanostructured composite materials. A detailed thermodynamic analysis was performed to determine the formation conditions of titanium and zirconium borides and carbides in the Ti–B–O–C and Zr–B–O–C systems. The complete thermodynamic analysis was carried out in vacuum for the reactions 2TiO2 + B2O3 + 8C = TiB2 + TiC + 7CO and 2ZrO2 + B2O3 + 8C = ZrB2 + ZrC + 7СО. On the basis of the theoretically found results, experimental synthetic routes were developed to prepare TiB2/TiC and ZrB2/ZrC composite materials.

    Keywords: thermodynamic analysis; synthesis; composite materials; carbon; titanium dioxide; zirconium dioxide; boron oxide