Objectives. To investigate the regularities of the process of joint production of epoxycyclohexane, cyclohexanol, and cyclohexanone using the cyclohexene epoxidation reaction with cyclohexyl hydroperoxide in the presence of an ammonium paramolybdate catalyst, representing an alternative to the method of cyclohexanol and cyclohexanone synthesis by alkaline catalytic decomposition of cyclohexyl hydroperoxide.

Methods. The qualitative and quantitative analysis of the obtained intermediate and target compounds was determined using modern physicochemical research methods: gas–liquid chromatography using the Chromatec-Crystal 5000.2 hardware and software complex with a flame ionization detector and infrared spectroscopy on an RX-1 infrared Fourier spectrometer. The content of hydroperoxide in the oxidation products was determined using iodometric titration, while the carboxylic acid content was determined by the titrimetric method based on the neutralization reaction.

Results. The presented method for obtaining cyclohexanol and cyclohexanone together with epoxycyclohexane by the reaction of cyclohexene epoxidation with cyclohexyl hydroperoxide containing cyclohexane in the products of high-temperature liquid-phase oxidation is experimentally substantiated. The influence of various technological parameters on the process of liquid-phase oxidation of cyclohexane to hydroperoxide is described. The conditions for carrying out this reaction are determined to ensure the achievement of a content of cyclohexyl hydroperoxide of 1.5 wt % in the products of oxidation. The regularities of the epoxidation reaction of the synthesized cyclohexyl hydroperoxide with cyclohexene in the presence of an ammonium paramolybdate catalyst are analyzed.

Conclusions. Epoxidation of cyclohexene with cyclohexyl hydroperoxide produced epoxycyclohexane at a yield of 80–90% and a conversion of cyclohexane hydroperoxide of 85%.

Objectives. Ferroelectric triglycine sulfate (TGS) belongs to a group of crystals whose properties are sensitive even to minor changes in growth conditions. The mechanism of spontaneous polarization in TGS is associated with the adjustment of protons which participate in the formation of hydrogen bonds. Therefore, the state of the parent solution plays an important role in the crystal formation. The study aims to investigate the structural features of TGS crystals grown using aqueous alcoholic solutions of technologically processed antibodies to interferon-gamma, in comparison with those of the crystals grown using the control solutions (technologically processed phosphate-buffered saline and intact aqueous alcoholic solution).

Methods. X-ray diffraction assay and Raman spectroscopy.

Results. The effect of solutions of the technologically processed antibodies to interferongamma added to a parent solution on the growth of TGS single crystals is established. This effect manifests in the changing in occupancy of the proton sublattice of the crystal grown from the parent solution containing technologically processed antibodies to interferon-gamma, as compared with the crystals grown from the control solutions. In the case of the crystal grown from the solution containing technologically processed antibodies to interferon-gamma, this change in the occupancy of the proton lattice is expressed in an increase in the length of N2–C3 bonds.

Conclusions. Adding the technologically processed antibodies in the parent solution before the crystal growth can affect the structure of TGS crystals.

Objectives. To investigate the swelling of the main types of rubbers used in the rubber industry in carbon dioxide in a supercritical state (SC-CO₂), in order to assess the possibility of obtaining elastomeric materials with porous structures using fluid technology, based on them.

Methods. The process of swelling of rubbers in SC-CO₂ and subsequent foaming was carried out according to a specially developed technique using the original installation. This is a high-pressure apparatus with transparent windows, allowing for the use of an optical technique to directly measure the geometric dimensions of samples during swelling and foaming using a digital video camera. The study of the porous structure of foamed rubbers was carried out using scanning electron microscopy.

Results. The study established experimental curves of the swelling kinetics in SC-CO₂ of isoprene, butadiene, styrene butadiene, ethylene propylene, chloroprene, ethylene acrylate, siloxane, and organofluorine rubbers. The influence of temperature and pressure on the rate and equilibrium degree of swelling was studied. The diffusion coefficients of SC-CO₂ in rubbers of various chemical natures were also determined.

Conclusions. It was shown that the equilibrium swelling degree of rubbers in SC-CO₂ depends on the chemical nature of rubbers. It does not correlate with the value of their solubility parameters, changes directly proportional to the diffusion coefficient and increases with increasing temperature and pressure. It was found that irrespective of the degree of swelling in SC-CO₂, all the rubbers studied are intensively foamed at a sharp pressure drop. The size of the pores formed is tens of microns: significantly smaller than the size of pores formed when chemical pore formers are used.

Objectives. To improve the technology for obtaining polymer spray coatings based on polycarbodiimides (polyureas) by studying changes in the process and operational parameters due to the introduction of aspartic acid derivatives (AADs) into the composition.

Methods. The process of the production of sprayed and contact polyureas involves a number of difficulties, not least in terms of the cost of the components and high-pressure equipment. For this reason, mathematical modeling was used to optimize experimental design. The curing time of the composition was measured under conditions simulated to be close to actual. After thermostating and mixing Components A and B in predetermined ratios, the gelation time was measured to represent the curing time of the composition. The hardness of the material was determined by the Shore method according to GOST 24621-91. Tensile strength and relative elongation were determined according to a standard method (GOST 30436-96).

Results. The effect of three AADs on the properties of the finished polyurea was studied. It was found that the introduction of two of them (AAD-1 and AAD-2) into polyurea in an amount of up to 40 wt % produces slow-curing (>250 s) polyureas capable of manual application. The finished products have physical properties on par with machine-poured materials (breaking strength >73 MPa; tensile strength >23 MPa; elongation >500%). Compiled regression equations were used to construct graphs of equal levels showing the possible areas of directed modification of the studied compositions.

Conclusions. AAD can be used as a modifying component for polyurea systems to obtain slow-curing polyureas with high performance properties, which can be purposefully controlled by mathematical modeling. The resulting products have commercial value due to their combination of valuable physical and mechanical properties.

Objectives. To develop a new green method for the synthesis of nanosized materials of cobalt(II,III) oxide, with improved surface activity, using environmentally friendly precursors and solvents.

Methods. A green method was proposed, in order to isolate Co₃O₄ nanoparticles with high surface activity. Instead of the usual organic solvents, three different natural sugars, including glycogen, sucrose, and glucose were used for the first time as templates. Water as a green solvent was used in all the steps. The polymorphic composition of the synthesized samples was determined by means of X-ray phase analysis. The morphology of the obtained crystallites was studied from micrographs of the oxide phases. Image Pro Plus 6 software was used to measure the size of nanoparticles. The surface activity of the isolated samples was studied using the Brunauer–Emmett–Teller method and the Langmuir method. The Barret–Joyner–Halenda method was used to determine the diameter, volume, and distribution of pores.

Results. The crystallite sizes of the samples are 23 nm, 36 nm, and 30 nm for glucose, glycogen, and sucrose templates, respectively. Adsorption–desorption isotherms for samples obtained from complexes of glucose and sucrose correspond to type IV, indicating a strong interaction between the adsorbent and the adsorbed sample. The isotherm for the sample isolated from the complex with glycogen is of a different type and most likely indicates that this sample is almost completely mesoporous. The pore radii are found in the interval 1.2–1.6 nm.

Conclusions. A new green method for the synthesis of nanosized particles of Co(II,III) oxide using natural saccharides and deionized water was developed. The composition, morphology, structure, and surface activity of the samples obtained were studied. It was shown that due to the polymeric structure of their metal complexes and the ability to bind active carbon on the surface of nanoparticles, natural saccharides can be used as matrices in the synthesis of nanosized metal oxides with high surface activity.

Objectives. To study the technological features of a new fluoride technology for the production of titanium dioxide by the decomposition of titanomagnetite concentrate with ammonium fluorides.

Methods. The chemical species of the titanium and iron components in the fluorination of titanomagnetite concentrate and sublimation separation of components were determined by means of X-ray powder diffraction analysis and inductively coupled plasma mass spectrometry. The kinetics of sublimation of the titanium component by the thermal decomposition of ammonium hexafluorotitanate was experimentally studied.

Results. The products of the fluorination of titanomagnetite concentrate with ammonium bifluoride are compounds (NH₄)₂TiF₆ and (NH₄)₃FeF₆, as proven by chemical analysis and X-ray powder diffraction analysis. The subsequent sublimation separation of the titanium component produced the target product: a mixture of ammonium fluorotitanates. The desublimation of the titanium-containing fraction gave an NH₄TiF₅–(NH₄)₂TiF₆–(NH₄)₃TiF₇ mixture, the titanium content of which is 30.6% and the content of impurities (Fe, V, Si) is a minimum (0.45%). The activation energy of the heterogeneous reaction and the rate-limiting step of the process were also determined.

Conclusions. A high-purity titanium product (a mixture of ammonium fluorotitanates) is obtained. This is a valuable commercial product for the industrial production of titanium dioxide pigment from titanomagnetite concentrate and ilmenite.

Objectives. To date, compounds of rare earth nitrates with urea in a ratio of 1:4 and indium in a ratio of 1:6 have been synthesized and structurally characterized. However, there is a lack of research into similar compounds having a lower urea content. The purpose of this work was to continue the search for regularities of structure formation for complexes of various elements with urea.

Methods. Novel coordination compounds were synthesized and characterized by powder- and single-crystal X-ray diffraction analysis, as well as infrared spectroscopy.

Results. The interaction of indium, gadolinium and erbium nitrates with urea (Ur) in an aqueous solution under conditions of ligand deficiency produces the previously unknown coordination compounds cis-[In(Ur)₄(NO₃)₂]NO₃, [Gd(H₂O)₂(Ur)₂(NO₃)₃], and [Er(H₂O)₂(Ur)(NO₃)₃]. The indium complex is shown to have an ionic structure, whereas the gadolinium and erbium complexes have a molecular structure. In the indium complex, the coordination number is 6; the cation has an octahedral structure; it involves two cis-arranged monodentate nitrate groups and four monodentate urea molecules. The coordination number of gadolinium is 10; here, the coordination polyhedron is a distorted pentagonal bipyramid at the vertices of which there are two water molecules, while in the internal polygonal base there are two monodentate urea molecules and three bidentate chelating nitrate groups oriented perpendicular to the polygonal base of the bipyramid. The coordination number of erbium is 9; the coordination polyhedron is a distorted tricapped trigonal prism.

Conclusions. In contrast with the gadolinium complex, one urea molecule is coordinated in the erbium complex instead of two, decreasing the coordination number from 10 to 9. In the indium complex cation, the coordination number is 6; unlike the gadolinium and erbium complexes, the cation does not contain water, and the nitrate groups are monodentate.