The mixtures of graphite and anthracite with lithium carbonate in atmospheres of argon and air were studied using differential scanning calorimetry (DSC). It was found that, in a temperature range of 100–500°C, the weight loss in argon was stronger than that in air. This phenomenon was caused by the removal of oxygen compounds with carbon. Competing processes of the formation of oxygen compounds with carbon and coal and the desorption of oxygen-containing substances occurred in air. The thermal effects for graphite–lithium carbonate systems in argon and in air were compared using DSC and gravimetry curves. It was found that the molar ratio between carbon(IV) and carbon(II) oxides in the reaction products up to 700°C can be estimated at 10 : 1. Endothermic effects of lithium carbonate melting in an argon atmosphere for the mixtures of graphite and anthracite with lithium carbonate were observed at 732 and 727°C, respectively. The peaks of endothermic effects in air did not correspond to the heat absorption curves in argon. The most probable explanations of the observed effects were given: the presence of lithium carbonate and lithium oxide phases and the manifestation of the stretched nature of the pre-transition region of lithium carbonate. Using powder X-ray diffractometry, it was found that the burnout of a carbon phase at 500°C in graphite and anthracite did not lead to a significant change in the interplanar distances in lithium carbonate.

The results of the synthesis and identification of complex compounds of hexamethylenetetramine (CH2)6N4 (HMTA) with tungsten phosphate metallates are presented. The processes and crystalline products of thermal decomposition of compounds with the general formula Cat5[PW11O39Z(HMTA)]∙nH2O, where Cat = Na+, NH_4^ + ; Z = Co2+, Ni2+, Zn2+; n = 10–13 have been studied by differential scanning calorimetry, IR spectroscopy, and X-ray powder diffraction. The schemes for their thermolysis have been established. It has been shown that ammonium salts during thermolysis form phases of the composition ZO⋅0.5P2O5⋅11WO3 or Z6/73P6/73W66/73O3 with the structure of phosphotungsten bronze. The decomposition products of sodium salts are a mixture of phases with the structures of sodium tungstates Na2W2O7 and Na2W4O13. The research results can be used to predict thermal transformations and the composition of thermolysis products of similar complexes of HMTA and tungsten phosphate metallates of other 3d elements.

Polyoxotungstosilicates with the general formulas Cat4[SiW12O40] · mH2O and Cat6[SiW11O39Ni(H2O)] · nH2O were synthesized, where Cat = Rb+, Cs+, (CH3)4N+. By means of IR spectroscopy and x-ray diffraction analysis, it was shown that the compounds have the Keggin anion structure. The thermolysis of the obtained compounds within the temperature range of 600 – 800°C resulted in the formation of previously unknown pyrochlore-structure phases Rb12/13Si2/13W22/13Ni2/13O6 and Cs12/13Si2/13W22/13Ni2/13O6 with the with the unit cell parameters a of 10.284 and 10.309 Å, as well as phases with tungsten bronze structure Rb12/20Si3/20W36/20O6 and Si3/38W36/38O3. The synthesis of tungsten silicates with pyrochlore and tungsten bronze structure through thermolysis of polyoxotungstosilicates reduces the temperature of their preparation to 600 – 650°C and heating time to 1 h, thus extending the ranges of chemical compositions and their morphological diversity.

In the course of this work, the characteristics of water absorption, contact angle, surface using natural energy, samples of cement stone from well cement and CEM A/II - 42.5 N with the addition of additives based on lecithin extraction waste were studied. The strength characteristics of cement stone with the addition of additives based on lecithin extraction waste were also confirmed. It has been established that the addition of 0.5% technical lecithin to cement reduces water absorption to 4.5%. It was revealed that an increase in soy lecithin in the amount of 0.1% leads to water absorption of cement stone based on well cement up to 6.35%. Oxalate-fatty sediment, when added to cement stone based on well cement with a wave force with a charge force, water absorption of the liquid is up to 8.15% with an additive content of 0.5%. The best results in reducing water absorption in cement stones based on CEM A/II - 42.5 N are observed with an oxalate-fatty sediment content of 0.5% and measured values of 2.81%. In the case of remaining exposure, water absorption changes only slightly. The wetting edges of the samples were measured and the surface free energies were calculated. The strength characteristics of cement stone samples based on CEM A/II - 42.5 N with the addition of additives based on lecithin extraction waste were measured.

The physicochemical processes occurring in glasses of the PbO–CdO–SiO2–B2O3–Al2O3 system after high-temperature contact with oxides of various metals—CuO, NiO, Al2O3, TiO2, Nb2O5, and WO3, as well as the electrical resistance of the obtained glasses—are studied by X-ray phase analysis, infrared spectroscopy, and electron paramagnetic resonance. It is established that these properties are determined by the acid-base and redox properties of the oxides and glasses, which directly depend on the content of the O2– ion in each specific composition.

The carbonization of carbohydrates (glucose, sucrose, and starch) in an inert gas atmosphere of argon and under the action of calcium chloride and iron(III) chloride additives was studied. It was established that the addition of calcium and iron(III) chlorides exerted a peculiar catalytic effect on the carbonization process. Carbon production can be carried out at lower temperatures to 200°С. In traditional methods of synthesis, carbonization upon the decomposition of carbohydrates occurs at temperatures of 300–800°C. It was found that the process of carbon production was accompanied by the release of heat, which was confirmed by thermodynamic calculations of the chemical reaction of carbon production and experimental studies of the carbonization of carbohydrates by differential scanning calorimetry. A regular decrease in the yield of carbon, as compared to a maximum theoretically possible one, was observed in the order glucose > sucrose > starch. It was established that the heat of combustion of carbon obtained upon the carbonization of carbohydrates under the action calcium and iron chlorides reached 34 MJ/kg or more due to the presence of structural fragments that do not occupy energetically favorable positions compared to the graphite structure. The presence of the structural fragments of carbon was established by X-ray phase analysis of powder diffraction patterns.

Thermolysis of ferrocenium tungstophosphate [(C5H5)2Fe]3[PW12O40]∙H2O and tungstophosphatoferrates with the general formula Cat4[PW11O39Fe(H2O)]∙mH2O [Cat = (NH4)+, Rb+, Cs+, (CH3)4N+] and the Keggin anion structure were studied using differential scanning calorimetry, infrared spectroscopy, X-ray phase analysis, and electron microscopy. The crystalline products of their thermal decomposition, phases with the structure of pyrochlore and tungsten bronzes, were identified. The synthesized compounds are catalysts for the reactions of organic compounds oxidation and the production of carbon nanomaterials.

Tungstophosphatozincates with the Keggin anion structure Kt5[PW11O39Zn(H2O)]∙nH2O, Kt = Rb+, Cs+, (CH3)4N+; (C2H5)4N+ were synthesized. Their thermolysis process was studied by differential scanning calorimetry, thermogravimetry, infrared spectroscopy, X-ray diffraction analysis and electron microscopy. The products of their thermal decomposition, phases with the pyrochlore structure and tungsten bronzes, were identified.

We present the results of the synthesis, investigation of thermal decomposition, and identification of thermolysis products of tetramethylammonium and tetraethylammonium salts of phosphotungstate metalates with cobalt, nickel, or copper in the coordination sphere of the complex, which are promising compounds in the fields of materials science, catalysis, and medicine. Compounds with the Keggin anion ([(CH 3 ) 4 N] 5 [PW 11 O 39 Z(H 2 O)]⋅ n H 2 O and [(C 2 H 5 ) 4 N] 5 [PW 11 O 39 Z(H 2 O)]⋅ m H 2 O, where Z = Co 2+ , Ni 2+ , or Cu 2+ ) have been synthesized from aqueous solutions. Their thermal decomposition and crystalline decomposition products have been characterized by differential scanning calorimetry (DSC), thermogravimetry, IR spectroscopy, X-ray powder diffraction (XRD), and electron microscopy. A general scheme of their thermolysis has been proposed. It has been shown that phosphorus, cobalt, nickel, and copper ions enter ZO ⋅ 0.5P 2 O 5 ⋅11WO 3 or Z 6 / 73 P 6 / 73 W 66 / 73 O 3 phases with the phosphor tungsten bronze structure; phases with similar chemical composition have not been documented previously. The results of this work can appear useful in predicting the thermal properties and phase compositions of thermolysis products of similar polyoxometalates in order to manufacture new related materials.

Introduction. The article proposes a model for assessing the integrated safety of the labor process of workers with the risk of the spread of infectious respiratory diseases, for the development of which multifactorial dependences of occupational risk on working conditions at the workplace were used, taking into account the likelihood of contracting coronavirus infection. Problem Statement. The objective of this study is to formulate methodological aspects of ensuring the safety of the workplace and the working environment, reflecting the need for constant epidemiological monitoring of objects of control (employees and the ways of virus transmission) with an assessment of the controlled parameters. Theoretical Part. Official data provided by the Federal State Statistics Service was used as basic information. Conclusion. The results of the analysis indicate the need for a rapid assessment of occupational risk, taking into account the epidemiological circumstances

Calorimetric and gravimetric measurements of C-3 spectral graphite and OU-B activated carbon dispersions in an inert gas atmosphere of argon were performed at different temperatures. These studies are of considerable current interest in graphite and activated carbon technologies. It was established that the weight loss in an inert gas atmosphere at temperatures to 1000°C is an important parameter for the physicochemical characterization of graphites and activated carbons.

The article deals with the synthesis, study of thermal decomposition and identification of the thermolysis products of cesium tungstophosphates that are promising compounds in the field of materials science, catalysis and other fields of science and technology. Compounds with the Keggin anion structure are synthesized from aqueous solutions: Cs3[PW12O40] ∙ 9H2O; Cs5Na2[PW11O39(H2O)] ∙ 5H2O and Cs5[PW11O39Ni0,5Cu0,5(H2O)] ∙ 4H2O. The processes of their thermal decomposition are investigated and some regularities of their thermolysis are established. Thermolysis products are identified: Cs3PW12O40, phases with the structure of pyrochlore and hexagonal tungsten bronze of the composition Cs10/13Na4/13P2/13W22/13O6 and Cs10/13P2/13Ni1/13Cu1/13W22/13O6. The unit cell parameters of the phase with the pyrochlore structure are determined. Research results confirm that phosphorus, nickel and copper ions are included in the structure of pyrochlore and hexagonal tungsten bronze. Phases similar to this chemical composition are not previously known in the literature. The studied tungstophosphates and their thermolysis products are promising compounds for obtaining heterogeneous catalysts for the oxidation of organic compounds and selective sorbents. The research results can be useful for predicting the thermal properties and phase composition of thermolysis products of similar polyoxometallates in order to obtain new compounds with the structure of pyrochlore and hexagonal tungsten bronze, as well as composite materials based on them.

This paper reports the synthesis of compounds with the pyrochlore and hexagonal tungsten bronze structures via thermal decomposition of heteropolyoxometalates. Using aqueous solutions, we have synthesized tungstophosphatometalates with the Keggin structure and the general formula Ct5[PW11O39(H2O)Z]⋅nH2O, where Ct = Rb+ or Cs+ and Z = Co2+, Ni2+, or Cu2+. We have studied the thermal decomposition of these compounds and identified their thermolysis products: phases with the pyrochlore and hexagonal tungsten bronze structures. Our results confirm that phosphorus, cobalt, nickel, and copper ions become incorporated into the pyrochlore and hexagonal tungsten bronze structures of the CtnxPxZxW2–2xO6 compounds. No phases with similar chemical compositions have been reported previously. Their synthesis temperature has been lowered by 200°C and the calcination time has been reduced by a factor of 2 in comparison with conventional synthesis methods. The proposed schemes of thermolysis of rubidium and cesium tungstophosphatometalates will be useful for predicting the thermal properties and phase composition of thermolysis products of analogous heteropolyoxometalates in designing new inorganic materials based on them.

The information on the compatibility of lead–boron–silicate glass of various compositions and ruthenium(IV) oxide compounds is systematized. The chemical processes occurring between them are established in terms of the theory of the acid-base interaction. The informative indicators that determine the direction of such interaction are the acidity, ionic potential, or orbital electronegativity of the components included in the composite materials. The established regularities can be used for selecting the composition of lead- and cadmium-free glass in the development of advanced ruthenium resistors and ruthenium-containing materials.

The chemical processes of manufacturing thick-film ruthenium resistors, which are accompanied by an acid-base interaction between the inorganic components of the paste, were studied. The regularities of composition formation and consumer properties of the resistors were determined.