Open Access
Access granted
Subscription Access
Vol 487, No 2 (2019)
- Year: 2019
- Articles: 9
- URL: https://journals.rcsi.science/0012-5008/issue/view/9323
Chemistry
Synthesis of New Sodium Pectinate Metal Complexes with Cobalt and Nickel Ions and Their Antimicrobial Activity
Abstract
New water-soluble nickel and cobalt complexes—sodium cobalt pectinate (PNaCo) and sodium nickel pectinate (PNaNi)—have been obtained from sodium pectinate with a salt formation extent of 35%, and their physicochemical properties have been studied. Antimicrobial activity of PNaCo and PNaNi against gram-positive and gram-negative bacteria and fungi has been shown.
207-211
212-214
Novel Ferrocene-Containing Thiophene Derivatives
Abstract
A new 2-amino-4-ferrocenylthiophene-3-carbonitrile has been obtained by Gewald reaction, the compound has been converted into Schiff bases as precursors for new optoelectronic and magnetic materials. The structure of the prepared compounds has been established by elemental analysis, IR spectroscopy, and 1H NMR.
215-217
Chemical Technology
A New Method for Synthesis of Fine Crystalline Magnesium Aluminate Spinel
Abstract
A new method for synthesis of high-purity fine crystalline magnesium aluminate spinel (MgAl2O4) has been proposed by treating a mixture of finely divided MgO and aluminum hydroxide (Al(OH)3) or oxyhydroxide (AlOOH) with aqueous fluid under supercritical conditions (T = 380–400°С, Р\(_{{{{{\text{H}}}_{{\text{2}}}}{\text{O}}}}\) = 22.8–23.0 MPa). It has been demonstrated that the formation of the magnesium aluminate spinel structure occurs by a solid state mechanism. The new method of synthesis makes it possible to control the size (from 20 nm to 5 µm) and shape (spherical, lamellar, or bipyramidal) of the synthesized magnesium aluminate spinel (MgAl2O4) by varying the reaction conditions.
218-220
Oat-Hull Cellulose Nitrates for Explosive Compositions
Abstract
Cellulose nitrates corresponding in the basic properties to high-viscosity lacquer-grade colloxylin were prepared by esterification of cellulose pulp, isolated from domestic rapidly renewable feedstock—agroindustrial waste—oat hulls, or cotton cellulose with a sulfuric and nitric acid mixture. The experimental samples of cellulose nitrates were comparatively evaluated. The IR and 13С NMR spectroscopy data confirmed the identity of chemical structure. High chemical purity of samples was confirmed by differential scanning calorimetry and ampule chromatography procedure. The cellulose nitrate samples have satisfactory mechanical sensitivity level: the lower limit of impact sensitivity is 50 mm and that of friction sensitivity is 1200 kgf/cm2; they have good chemical compatibility and high chemical stability when blended with plasticizers. The obtained results attest to expediency of using cellulose nitrates from oat hulls as a component of explosive compositions.
221-225
Synthesis of Nanostructured Island Alumina Coatings on the Surface of Macropores of Hierarchically Porous Nickel
Abstract
226-229
Pyrolysis of Derivatives of Technical Mixtures of Polychlorinated Biphenyls
Abstract
The thermal stability and composition of the gas phase of the most common technical mixtures of polychlorinated biphenyls of the Sovol and Trikhlorbifenil brands have been studied by simultaneous thermal analysis and mass spectrometry in comparison with their derivatives synthesized by the reaction of these mixtures with sodium methoxide in a medium of dimethyl sulfoxide and methanol. It has been determined for the first time that derivatives of polychlorinated biphenyls are less thermally stable compounds in comparison with the initial substances and, in pyrolysis, undergo not only evaporation but also decomposition to the simplest volatile species. The thermal destruction of the derivatives requires lower energy consumption and is characterized by lower emissions of hazardous chemicals.
230-234
External Friction in SHS Compaction
Abstract
Reverse pressing under the active action of external friction force was theoretically analyzed based on the previously developed rheodynamic models of high-temperature SHS compaction. It was shown that, in this pressing method, external friction is a useful technological phenomenon, which allows one to reach a uniform density distribution in the bulk of the material of the workpiece. Analytical expressions for calculating the characteristic pressing time and the pressure distribution were obtained.
235-237
Erratum
238-238