A comprehensive physico-chemical study of individual systems provides important experimental data, which can be further used both in basic and applied research. Thus, a number of systematic studies have revealed the formation of complex molybdates, which can be classified in terms of cationic composition. Many compounds belonging to this class are shown to possess valuable functional properties. In this work, we set out to generalise and complement the results obtained on phase formation in K2MoO4 – R 2 (MoO 4 ) 3 – Zr(MoO 4 ) 2 salt systems (R = Al, Cr, Fe, In, Sc, Y, Bi, La –Lu) dependent on the nature of the molybdates of trivalent elements. In addition, we aim to determine synthesis conditions and to characterise properties of these triple molybdates. To this end, methods of X-ray phase analysis, differential scanning calorimetry, electron microscopy and impedance spectroscopy were used. Interaction in ternary salt systems K 2 MoO 4 – R 2 (MoO 4 ) 3 – Zr(MoO 4 ) 2 (R = Al, Cr, Fe, In, Sc, Y, Bi, La – Lu) was studied at subsolidus temperatures across the 723–873 K range. Transformation of phase diagrams was demonstrated; the systems were divided into ten triangulation types. The identified new triple molybdates of the K 5 RZr(MoO 4 ) 6 (R = Al, Cr, Fe, In, Sc, Y, Bi, Dy - Lu) composition were obtained via solid-phase synthesis at temperatures of 723–773 K. Their crystallographic and thermal properties were determined. Molybdates of the K 5 RZr(MoO 4 ) 6 composition are established to crystallize in a hexagonal crystal system and a trigonal crystal system under R = Al, Cr, Fe, In, Sc (space group P63, Z = 2) and under R = Dy - Lu, Y, Bi (space group R`3c, Z = 6), respectively. The electrical conductivity of K 5 RZr(MoO 4 ) 6 (R = Fe, In, Er) was studied using the method of impedance spectroscopy across the temperature range of 300–900 K. It is also demonstrated that the conductivity values of this compound amount to 10 -2 S/cm at 700–850 K.

Petroleum and coal pitches are known to be among the most important sources of raw materials for the production of carbon materials, including electro-carbon, heat- and chemical-resistant structural products, metal-carbon and carbon-carbon composite materials, graphite electrodes, self-baking anode paste, carbon fibres, blast furnace and cupola coke. The quality of the pitches is determined by the elemental and group composition, as well as their structural and physical-chemical properties. The study of the molecular structure and group composition of the organic components of the pitch and the identification of the effect of the composition on the performance of the products is of great interest for assessing the prediction of the behaviour of pitches during processing and the properties of the products obtained from them. The present work is devoted to the study of the group composition of two petroleum and two coal pitches using high-resolution NMR spectroscopy. The data of the ¹H and ¹³C NMR spectra allow the composition of the pitch product to be estimated without separation into fractions, which, in turn, combined with the accuracy of the method and the recording speed of the ¹H NMR spectra, increases the rapidity of this method of analysis. The combination of ¹N and ¹³C NMR data allows additional information on the correlation of physical parameters and pitch composition to be established. The calculation of the (H ar /H al ) parameter, corresponding to the ratio of the integral intensities of signals of aromatic and aliphatic hydrogen atoms, provides the possibility of using it as a structural characteristic for a particular sample. In order to ensure the correct contribution to the integral intensity of the signals, ¹³C NMR spectra were recorded in a pulse sequence with suppression of the spin-spin proton interaction only for the period of data reading for the purposes of minimising the nuclear Overhauser effect. The relaxation delay between pulses was set to 10 s. The study of petroleum and coal pitches using NMR spectroscopy showed the proton spectra of NMR data to be sufficiently informative and suitable for monitoring the technological process of pitch production.

An increased fire hazard of lignite drives the need to study its propensity to self-combust resulting from possible self-heating, which eventually leads to its ignition. Coals formed by low-grade metamorphism are subject to these dangerous processes to a greater degree. Availability, large reserves and low cost of these natural coals, as well as appropriate physical and chemical properties make them indispensable in carbon activation. Activated carbons, in turn, are employed for carrying out various processes in hydrometallurgy; for removing impurities of inorganic and organic origin from industrial wastewater; for purifying industrial gases. Moreover, activated carbons are used in medicine and other economic sectors. In this study, we determined the kinetic parameters characterising the fire hazard associated with spontaneous combustion of lignite during its treatment in the course of carbon activation. Lignite from a well-known large Irsha-Borodino deposit of the Kansk-Achinsk basin was selected as the object of study. Dispersity was chosen as the main physico-chemical parameter, since its value has a significant impact on the creation of hazardous conditions for self-heating of dispersed materials. In order to choose a research procedure, an analysis of known methods for evaluating the propensity of dispersed substances to spontaneous combustion was performed. Spontaneous combustion of lignite was studied using an improved method of calorimetry, allowing investigation of this process in terms of materials dispersity. The rate of heat release during spontaneous combustion of lignite, as well as the main kinetic parameters (effective activation energy and pre-exponential factor), were determined. The obtained values of the kinetic parameters show that a decrease in the dispersity and consolidation of crushed lignite particles (Irsha-Borodino deposit, Kansk-Achinsk basin) significantly raises the propensity of these coals to self-heating and eventual spontaneous combustion. The obtained results can be used for developing measures aimed at reducing the fire hazard involved in lignite processing technologies employed in the course of carbon activation. Compliance with specific recommendations on controlling the self-heating process and resulting spontaneous combustion can be achieved by forecasting conditions for the increase of coal temperature through controlling kinetic parameters.

Hawthorn berries are traditionally used as a medicinal raw material in folk medicine. This plant contains important organic acids and flavonoids, such as carotene, pectin, ascorbic acid, saponins, starch and group B vitamins, which are believed to facilitate the restoration of the cardiovascular system. Medicinal raw materials are primarily used in the form of extracts. In this work, we use three extraction technologies: one conventional technique, i.e. infusion (37 °С, 2 hours), and innovative ones involving the use of microwave (800 W, 1 min) and ultrasonic irradiation (0.5 W, 2 hours). In order to determine the most optimal method for obtaining a complex of substances exhibiting antioxidant properties from hawthorn fruit extracts, we studied the content of dry substances, phenols and flavonoids. In addition, the antioxidant activity was determined by trapping free radicals and using the FRAP method (restoring force). On the basis of the obtained experimental results, the hawthorn fruit extraction conducted using ultrasonic irradiation is found to be the most effective of all the considered technologies, since it yields the highest values for all the studied parameters as compared to other extraction methods. Thus, the following levels were achieved: phenols – 723 mg of gallic acid per 100 g; flavonoids – 194 mg of catechin per 100g; dry substances – 1.68 %; anti-radical activity – 14.5 mg/cm3 ; restoring force – 14.5 mmol of Fe2+ per 1 kg. Our results show that the extraction using microwave irradiation cannot be recommended, since the values obtained using this method are lower than those obtained by ultrasonic irradiation and infusion.

This paper provides an overview of the features specific to the nuclear magnetic resonance (NMR) of paramagnetic molecules. These features can be attributed to the hyperfine or electronic coupling between unpaired electrons, which are localised on the coordinating ion, and resonant nuclei. That leads both to the paramagnetic broadening and to the paramagnetic shifts (contact and pseudo-contact ones) of resonance lines in the NMR spectra. A contact shift is observed when the probability of an unpaired electron location in the place of a resonant nucleus differs from zero. Therefore, these shifts constitute a source of information on the nature of the metal-ligand bond as well as on the ligand electronic structure. Pseudo-contact shifts characterise the spatial structure of the molecule, thus being important for solving various structural problems. This paper covers pioneering works describing the specifics of the NMR spectra transformed by adding paramagnetic complexes of iron-group elements on the example of cobalt and nickel complexes, as well as complexes of rare-earth elements on the example of europium. We present main features of the paramagnetic additives method, allowing resolution of difficulties associated with large paramagnetic broadening of resonance lines in high-resolution NMR spectra. Of iron-group elements, a paramagnetic ion Co 2+ is shown to be an effective shift reagent. In some cases, a Ni 2+ ion may also be used for this purpose. The paper covers conditions for recording the NMR spectra of samples containing paramagnetic additives; solvents used for this purpose; as well as temperature variations of the studied samples in the context of resonance signal detection.

The activity coefficient of individual ions is an important parameter in the theory of strong and weak electrolytes in aqueous and non-aqueous solutions. The physical meaning of the average ion coefficient lies in the ratio of the practical and theoretical activity coefficients. If the activity coefficient is set equal to 1 .0, as in the majority of published works, the final calculations can present multiple distorted γ± results. The activity coefficient constitutes a measure of the deviation of real (practical or experimental) parameters from the ideal ones. Ideal parameters are calculated for dilute solutions of non-electrolytes, in which no interactions are assumed to occur. Activity coefficients in high-concentration solutions may reach the values of several tens. However, some empirical data has indicated the dependence of the activity coefficient of electrolytes on their concentration, with some concentrations showing its minimal values. The coefficients equal to several tens, i.e. describing deviations from ideal parameters by the factor of ten, are difficult to adapt for practical application in solutions where association processes or other intermolecular interactions dominate. The present paper describes a number of methods for estimating the average ionic activity coefficients of such strong acids as hydrochloric, hydrobromic, hydroiodic, perchloric, nitric and sulphuric acids across the concentration range from 1 to 10 mol/l. These methods are based on the concepts of nonlinear programming and the method of multi-level modelling of various properties and parameters applied as a calculation tool. According to the performed calculations, the as-estimated activity coefficients of the acids under study are found to be in good agreement with the literature data for the concentration range from 1 to 10 mol/l.

Benzylidene protecting groups are widely used in carbohydrate chemistry, as a rule, to protect the hydroxyl groups at O-4 and O-6 positions of the carbohydrate residue. With varying degrees of selectivity, 4,6-benzylidene protection allows introduction of other functional groups at O-2 and O-3 positions of sugars and is easily removed from the molecule under acidic conditions. We have previously proposed a scheme for obtaining acyl derivatives of natural glycoside salicin (glycoside of salicylic alcohol) from the intermediate glycoside helicin (glycoside of salicylic aldehyde). The aldehyde group can be reduced to alcohol during the final synthesis stages. Moreover, this group does not require additional protection during the modification of the carbohydrate residue, since it does not participate in acylation reactions, unlike the hydroxymethylene group of salicin. For the temporary protection of O-4 and O-6 hydroxyls of helicin, it was proposed to use a benzylidene protecting group. In this paper, we set out to study the reactivity of helicin in the reaction of 4,6-benzylidene formation, as well as to establish factors affecting such processes. Attempts were undertaken to introduce a benzylidene protecting group into a helicin molecule in two ways: using benzaldehyde dimethyl acetal, as well as using benzaldehyde and zinc chloride. In the former case, the conversion of the original glycoside was not observed, while the second reaction resulted in the product of an unidentified structure. Possible reactions occurring with the reagents applied were modelled using quantum-chemical calculations. It is found that the inability of benzaldehyde dimethyl acetal and benzaldehyde to react on 4,6 hydroxyls of glucose is explained by the competing reaction of the aldehyde group in the structure of helicin. Moreover, the catalysis with zinc chloride most likely produces a helicin dimer. Thus, it is found that benzylidene protection has certain limitations and cannot be applied in the case of glycosides containing aromatic aldehydes as the aglycone part.

This paper is aimed at developing a technology for obtaining encapsulated forms of biologically active substances exhibiting antioxidant properties from secondary agricultural materials. A technology for ultrasoundassisted extraction of antioxidants followed by their encapsulation was developed. We studied the structural and functional interactions between the structural units of biopolymer capsules using the methods of Fourier transform infrared spectroscopy. The spectrum of alginate capsules containing extract shows a number of differences as compared to those of capsules without extract, which indicates successful inclusion of biologically active plant substances (peak intensity varies within the range of 800–1600 cm-1 , 1240.30 cm-1 and 1512.26 cm-1 ). However, these changes do not suggest any significant chemical interactions between the biopolymers and the encapsulated substance. The results of the developed encapsulated antioxidants in terms of their size, moisture, encapsulation efficiency and yield, extract content, as well as other physico-chemical parameters were similar to each other and in good agreement with literature data. The experiments showed that all of the capsules began to swell to varying degrees in an artificial intestinal tract due to increased electrostatic repulsion forces. The obtained results on the change in mechanical properties of the developed capsules show the degradation of the capsules (with the values of capsule strength tending to zero) to occur with time and under the influence of alkaline conditions and monovalent ion salts. These facts confirm the feasibility of developing encapsulated antioxidant forms from secondary agricultural materials, which can help bridge the deficiency of bioactive substances in the human diet in the bioavailable form.

The article presents the results of research into the biotechnological processing of collagencontaining raw materials (bovine rumina) to create functional foods. The patterns of biotransformation of collagen-containing raw materials by activated cultures of probiotic microorganisms (Bifidobacterium longum B379 M, Propionibacterium shermanii KM 186 and Lactobacillus helveticus Н17-18) have been studied and theoretically substantiated. It is noted that bovine rumina, following preliminary heat treatment, comprise a good nutrient medium for the development of probiotic cultures. It was revealed that low-molecular compounds formed during the heat treatment of rumina possess prebiotic properties that stimulate the growth of microorganisms. It was established that after 5–8 hours of cultivation, the number of viable cells of the studied cultures in the collagen substrate increases to 10 9 –10 10 CFU / g. It is noted that the biomodification of rumina improves their organoleptic properties and consistency, causing it to become succulent, soft and ductile. Biotransformation of collagen-containing raw materials by probiotic microorganisms leads to a significant increase in amino acids in hydrolysates in comparison with the control sample. The greatest increase in amino acids is observed during the fermentation of collagen Lactobacillus helveticus H17-18, which indicates a higher proteolytic activity of this culture. It was shown that the rumen microstructure undergoes changes under the action of probiotic microorganisms in comparison with the initial state (the muscle carcass becomes thinner and looser, as well as undergoing change in terms of the structure of its morphological elements). As a result of the research, a fundamentally new scheme of biotechnological processing of collagen-containing raw materials was developed. The obtained results open up broad prospects for the creation of BAA-synbiotics and food products intended for functional nutrition.

In this article, a description of the photochemical degradation of phenol with TiO 2 nanoparticles for the treatment of toxic substances in water basins is presented. Such research is of great relevance due to the discharge of wastewater into clean water basins resulting in a contamination of ecosystems with very ecological consequences. Due to the seemingly inevitable reduction in the world’s freshwater reservoirs, finding new methods for the high-level purification of contaminated waters so as to minimise the toxic substance content is of paramount importance. Composition and quantitative analysis of the photolysis solution was carried out using the gas chromatographic method. TiO 2 nanopowders were prepared using the sol-gel method from titanium IV isopropoxide (TTIP), isopropyl alcohol and ammonium hydroxide precursors under normal conditions without any post-heat treatment for crystallisation. The nanocrystalline rutile-phase TiO2 powders were characterised by X-ray powder diffraction (XRD). The size of nanoparticles as confirmed by transmission electron microscopy (TEM) was about 10–20 nm, while the Brunauer–Emmett–Teller (BET) specific surface area of the rutile nanopowder was 159.6 m 2 /g. The photocatalytic performance of the synthesised nanopowders photochemical was observed to enhance degradation of the phenol solution under UV irradiation. The phenol degradation was quantitatively analysed using a 6890N GC-MSD gas chromatograph with an Agilent 5975 highperformance mass-selective detector. Degradation of phenol in the presence of TiO2 nanopowders yielded a rate of 99%.