T. A. Udalova

Precipitation of bismuth(III) salicylates from mineral acid solutions

Powder X-ray diffraction, IR spectroscopy, Raman spectroscopy, thermogravimetry, and chemical analysis were used to study the precipitation of bismuth(III) salicylates from perchloric, nitric, and hydrochloric acid solutions as dependent on the salicylate ion concentration, temperature, and pH. Depending on the synthesis parameters, precipitation from perchloric and nitric acid solutions yields monosalicylate BiOC7H5O3 or disalicylate Bi2O(C7H5O3)4.

Bismuth compounds in medicine

The methods of the X-ray analysis, IR- and KR-spectroscopy, thermogravimetry, the submicroscopies and chemical analysis are investigated conditions of precipitation synthesis inorganic insoluble bismuth-containing compounds for medicinal preparation by a carboxylic (or inorganic) acids (or salts) from bismuth-contained nitric solutions. The possibility of synthesis bismuth-containing compounds (e.g., bismuth nitrate, bismuth subnitrate, bismuth subcarbonate, bismuth subgallate, bismuth subsallicylate, tartrate, colloidal bismuth subcitrate, bismuth tribromphenolate, bismuth citrate) for medicine from bismuth-contained nitric solutions is shown. The conditions of obtainable the data high cleanliness bismuth-containing compounds are defined.

Synthesis of metal nanopowders by reduction in organic liquids

Possibilities of the method of obtaining metal powders by means of thermal decomposition (or reduction) of their compounds during heating in a medium of a high-boiling organic liquid were investigated. A distinguishing feature of the approach proposed is the use of benzyl alcohol as the liquid medium, while the initial metal carboxylates with different lengths of the methylene chain were formates, caprylates and stearates. It was demonstrated in the present work that the proposed method can be successfully used to synthesize various metals including nickel, copper, silver, bismuth, and it provides the possibility to obtain the powders either in the micron state or in the submicron (nano-sized) ones. The possibility to synthesize powdered alloys of these metals was also demonstrated.

Mechanochemical preparation of polymeric composites consisting of polyamide and clay materials

The mechanism of mechanochemical formation of composites consisting of PA-6 polyamide and clay minerals (pyrophyllite, kaolinite) was studied by IR spectroscopy and X-ray diffraction analysis. Composites with chemical bonding between the components are formed by activation of polyamide-pyrophyllite mixtures at polymer content c ≤ 10% and of polyamide-kaolinite mixtures at c ≤ 5%. Increased polymer content of the starting mixture “inhibits” the disordering of the silicate structure in the course of activation. Modification of polymers with mechanochemically formed polyamide/clay mineral composites improves the physicomechanical characteristics of the composite materials obtained.

Preparing Ultradisperse Copper Powder via the Mechanochemical Reduction of Copper Oxides by Magnesium

The mechanochemical reduction of copper (I and II) oxides by magnesium is studied by means of X-ray phase analysis, electron microscopy, and EDS elemental analysis. The conditions for separating copper particles from other products and protecting copper from oxidation during storage are determined. The sizes of the obtained aggregated particles of reduced copper (~100 nm) are estimated via scanning electron microscopy.

Synthesis of hafnium carbide by mechanochemistry and irradiation

The interaction in the Hf–C system during mechanical activation performed in a high-energy planetary ball mill and the irradiation-assisted fabrication of hafnium carbide from an Hf/C mechanocomposite are studied by synchrotron X-ray diffraction (at a quantum energy of 33.7 keV) and high-resolution scanning electron microscopy. The mechanochemical interaction results in the formation of an Hf/C mechanocomposite at the first stage and mechanical activation for ≥8 min forms hafnium carbide. The irradiation of the Hf/C mechanocomposite with a high-energy electron beam (~150 W/mm2) causes melting and spreading of hafnium over the carbon particle surface and the crystallization of hafnium carbide.

Mechanocomposites of biologically active acids on the basis of a natural biopolymer

Mechanical activation of the natural biopolymer arabinogalactan with organic acids (succinic, aminoacetic) was studied by IR spectroscopy and X-ray phase analysis. Evidence was obtained for the formation of mechanocomposites with a chemical bond between the natural biopolymer and organic acids. The nature of this bond depends on the nature of the acid. The composites obtained by mechanical activation of such mixtures are stable disperse systems with a uniformly distributed active ingrediaent.

Interaction of organic acids with silicates in the course of joint mechanical activation

IR spectroscopy, X-ray phase analysis, and high-resolution electron microscopy were used to examine the nature of the interaction of organic acids with silicates in their joint mechanical activation for the example of succinic acid. It was found that mechanocomposites with chemically bound components are formed in the course of activation of acid–layered silicate mixtures. It was shown that in the acid/nano-SiO2 composite, monomer molecules of the acid are bound to nano-SiO2 via molecules of adsorbed water, which form rather strong hydrogen bonds with the basic active centers of nano-SiO2 and hydroxy groups of the monomer molecules of the acid.

Synthesis of finely disperse nickel particles by thermolysis of complex (N2H5)[Ni(NH2NHCOO)3] · H2O in organic liquids and refinement of crystal structure of this complex

The crystal structure of the complex (N2H5)[Ni(NH2NHCOO)3] · H2O (I) was refined using X-ray diffraction data (obtained on an Apex X8 diffractometer, MoKα radiation, 1830 Fhkl, R = 0.0182). The structure is built of complex anions [Ni(NH2NHCOO)3]−, cations N2H5+, and water molecules and is characterized by strong hydrogen bonds N-H…O, O-H…O, and N-H…N. The N3O3 coordination polyhedron around a Ni atom is a slightly distorted octahedron. The thermal decomposition of complex I was studied in high-boiling organic liquids. The feasibility of preparing non-pyrophoric nickel powders having particle sizes of up to 20 nm is shown.

Synthesis of bismuth (III) salicylates in the precipitation reactions from solutions

The influence of salicylate-ion concentration, process temperature and pH of solutions on the bismuth precipitation degree from perchloric and nitric acids solutions and on the composition of forming were studied. It was demonstrated that bismuth could be precipitated from perchloric and nitric acid solutions as monosalicylate as well as disalicylate with the composition of BiOC₇H₅O₃ and Bi₂O(C₇H₅O₃)₄, respectively.