The paper describes an investigation of lubricants synthesized by thickening a dispersion medium consisting of silicone oil (PES-5) and poly-α-olefin oil (PAOM-12) with diureas of different compositions. The study revealed the effects of the compositions both of the dispersion medium and urea thickener, as well as their ratio in the lubricating formulation, on the major physicochemical properties of resultant greases. Increasing the content of the hydrocarbon component of the grease was shown to improve the physicochemical properties. Finally, the optimum grease composition was identified: introducing a polyurea thickener that contained diphenylmethane-4,4'-diisocyanate resulted in the synthesis of greases that had adequate operating characteristics and an improved wear performance.

A method is proposed for the preparation of antiwear additives based on quaternary ammonium salts of dialkyldithiocarbamic acids by non-catalytic interaction of stoichiometric amounts of the corresponding diamine, carbon disulfide, and tetraalkylammonium chloride in the presence of sodium hydroxide in which the interaction of the initial components is carried out in one stage. All synthesized additives are highly soluble in polyorganosilicone oils, and at a concentration of 0.5–1.0 wt

New dialkyldithio derivatives of 2,6-dimethylphenol have been synthesized and characterized. The multifunctional properties have been studied for the first time for these compounds as additives to lubricating oils in friction and wear processes under boundary friction conditions, as inhibitors of high-temperature oxidation of hydrocarbons, and as protectors of metal surfaces. It was determined that even a 0.5 wt % concentration of the synthesized additives in lubricating oils contain more than doubles anti-wear properties. It was shown that the additives exhibit a complex antioxidant effect and high efficiency at all stages of the oxidation process, and even at ultralow concentrations (0.005 wt %), their ability to resist oxidation exceeds widely used analogues. The new additives are of significant interest to modern lubricant science and can be used in motor oil formulations and other lubricants.

Metal–hypercrosslinked polystyrene (HCP) composites active in the hydrogenation of unsaturated hydrocarbons are obtained by impregnation of HCP with palladium and rhodium compounds in a supercritical carbon dioxide (SC-CO2) medium followed by their reduction to the metallic state with molecular hydrogen. The influence of the conditions of preparation of the composites on their activity and selectivity in the hydrogenation of diphenylacetylene (DPA) is evaluated. The adsorption of palladium hexafluoroacetylacetonate on HCP from an SC-CO2 medium is studied for the first time using supercritical fluid chromatography; it is shown that the adsorption equilibrium is described by the Langmuir equation.

Using a reaction between secondary amines, sodium hydroxide, and carbon disulfide followed by introducing methyl iodide into the reaction mixture, we synthesized and characterized a number of dialkyldithiocarbamic acid methyl esters that contained n -alkyl and iso -alkyl groups (C 2 –C 5 ). Tribological performance data were obtained for the compounds synthesized as they were added to synthetic lubricants. The additives were demonstrated to markedly improve the antiwear, antiseizure, and antifriction properties of the resultant lubricating compositions. The effects of the concentration and structure of the esters on the friction and wear parameters of the lubricants were investigated.

The review deals with the development of lubricants taking into account the requirements associated with the operation of modern electric vehicles and determined by the design features of both the vehicles themselves and their separate units. The scientific and technical literature concerning the development of lubricants for electric vehicles is analyzed. The base oils and functional additives that are used most frequently are indicated, and their advantages and drawbacks are discussed. Problems associated with the further development of basic and applied aspects of the modern lubricating materials science as applied to electric vehicles are considered.

To obtain a supported heterogeneous catalyst, laser ablation of metallic palladium in supercritical carbon dioxide was performed in the presence of a carrier, microparticles of γ-alumina. The influence of the ablation process conditions—including supercritical fluid density, ablation, mixing time of the mixture, and laser wavelength—on the completeness and efficiency of the deposition of palladium particles on the surface of the carrier was studied. The obtained composites were investigated by scanning and transmission electron microscopy using energy dispersive spectroscopy. We found that palladium particles were nanosized and had a narrow size distribution (2–8 nm). The synthesized composites revealed high activity as catalysts in the liquid-phase hydrogenation of diphenylacetylene.

A novel method for incorporation of palladium nanoparticles into a porous hypercrosslinked polystyrene matrix has been developed. The composite obtained by reduction of [Pd(π-allyl)Cl] 2 with hydrogen in supercritical CO 2 shows high catalytic activity in the hydrogenation of benzene and can be used twelve (12) times in a row without any decrease in conversion rate. The catalyst is also suitable for quantitative hydrogenation of toluene, tetralin and phenol. The obtained catalytic system is compared with the palladium composite synthesized by a conventional method based on hypercrosslinked polystyrene.

A novel method for the incorporation of iridium nanoparticles into a hypercrosslinked polystyrene matrix is developed using supercritical CO2 as reaction medium. The composite has regularly distributed iridium nanoparticles with monomodal size of ca 5 nm. The catalyst shows high activity in the hydrogenation of benzene and can be recycled ten times without any decrease in productivity. The catalyst gave a full conversion in the hydrogenation of toluene to methylcyclohexane and fluoro- and chlorobenzene to cyclohexane.

Composites—palladium metal particles in a polymer matrix—are obtained by impregnation of hypercrosslinked polystyrene with palladium compounds in supercritical carbon dioxide (SC-CO2) followed by molecular hydrogen reduction. The synthesized composites exhibit a high level of catalytic activity in the liquid-phase hydrogenation of diphenylacetylene (DPA). The turnover frequency (TOF) is 15–50 min–1 and the selectivity in the formation of diphenylethylene is 60–80% at ~90% conversion of the substrate.

Dedicated the memory of Akademician Valery Vasilievich Lunin, a friend, colleague, teacher, founder and leader of the research into application of supercritical fluids in chemistry. This review analyzes the rapidly developing applications of supercritical fluids, mainly supercritical carbon dioxide, in catalysis, chemistry of high-molecular-weight compounds, and medicinal chemistry in Russia and abroad. It considers the methods of catalyst preparation based on impregnation of inorganic and organic supports with metal-containing compounds, immobilization of organometallic and metal complex reagents in matrices of oxide and polymer supports, and deposition processes employing supercritical fluids. An analysis is presented of the prospects for applying CO 2 and some organic compounds, such as aliphatic alcohols, in sub- and supercritical states as reactants and (or) solvents for catalytic reactions of hydrocarbon isomerization and cracking, hydrogenation, dehydrogenation, oxidation, etc., including the asymmetric reactions. The review discusses processes of synthesizing and modifying polymer materials for various purposes, including aerogels, foams, and composites impregnated with photochromes, in a supercritical fluid medium. Special attention is paid to supercritical one-pot processes, which make the techniques of obtaining new materials simpler, less expensive, and more efficient. The work investigates the effect of supercritical CO 2 on the morphology, gas separation characteristics, and dielectric properties of polymers. One of the promising applications of supercritical fluids in medicine is the use in transplantology and pharmacology, for example, for the preparation of drug polymorphs with higher bioavailability. The review also provides an overview of the recent data on the use of EPR spectroscopy for studying the properties of supercritical fluids, including those exhibited in the vicinity of the critical point and identifying the intermediates of chemical reactions in such media.

The review deals with the development and production of synthetic additives to lubricating oils and plastic lubricants, influencing the friction and wear of metal surfaces. The state of the art of the synthesis and use of such additives based on organic, organoelement, and metal-containing compounds is considered. New synthetic routes to relatively safe and low-toxic compounds with minimal content of environmentally harmful elements (chlorine, phosphorus, sulfur, metals) are described, and their use as antiwear additives to lubricating materials is analyzed. Despite large number of the suggested new antiwear additives, it is difficult to expect that an optimum combination of tribological properties will be reached in a molecule of a single additive as in the case of additives based on zinc dialkyl dithiophosphates.

Спроектирована и изготовлена установка для получения нанесенных гетерогенных катализаторов методом лазерной абляции металлической мишени в присутствии носителей различной природы в среде сверхкритического диоксида углерода (СК-С0). Выбраны условия импульсного лазерного воздействия (длина волны, частота, время), параметры среды СК-С0 (давление, температура) и конфигурация узлов установки (лазер, мишень, носитель и элементы визуального и оптического контроля). На этой установке при лазерной абляции металлического палладия осаждением на у-оксид алюминия в среде СК-С0 получен композит, представляющий собой AlO с частицами Pd. При изучении синтезированного композита в качестве катализатора жидкофазного гидрирования дифенилацетилена показана его высокая активность (TOF = 1,45 с) и высокая селективность в гидрировании одной тройной связи. An experimental setup was created to produce deposited heterogeneous catalysts by laser ablation of a metal target in the presence of various carriers in supercritical carbon dioxide (SC-CO). The conditions of pulsed laser exposure (wavelength, frequency, and time), SC-CO medium parameters (pressure, temperature) and the configuration of experimental setup (laser, target, carrier and visual and optical control elements) were worked out. A composite consisting of AlO with Pd particles was obtained by laser ablation of metal palladium with deposition onto у-alumina in a SC-CO medium. The synthesized composite has been studied as a catalyst for liquid-phase hydrogenation of diphenylacetylene and its high activity (TOF = 1.45 s) and high selectivity in hydrogenation of one triple bond has been shown.

Импрегнацией сверхсшитого полистирола соединениями палладия в среде сверхкритического диоксида углерода (СК-С0) с их последующим восстановлением молекулярным водородом получены композиты - частицы металлического палладия в матрице полимера. Синтезированные композиты проявляют высокую каталитическую активность в жидкофазном гидрировании дифенилацетилена, удельная активность (TOF) составляет 15-50 мин, селективность в образовании дифенилэтилена равна 60-80 % при ~90 %-ной конверсии субстрата. By impregnation of super-crosslinked polystyrene with palladium compounds in the medium of supercritical carbon dioxide (SC-CO) with their subsequent reduction by molecular hydrogen, composites - particles of metallic palladium in the polymer matrix were obtained. The synthesized composites exhibit high catalytic activity in the liquid-phase hydrogenation of diphenylacylene , specific activity (TOF) is 15-50 minr, selectivity in the hydrogenation of one triple bond is 60-80 % at ~90 % conversion of the substrate.

Colloidal stability of greases is one of the most important physicochemical parameters, which characterizes their working capacity and affects the mechanical strength and tribological properties. An integrated study of the colloidal stability of greases based on synthetic base oils with organic thickening agents demonstrated that the stability depends to a noticeable extent on quite a number of factors, such as the nature of a base oil and a thickening agent, presence of fillers, synthesis conditions, etc. A combination of these factors makes it possible to obtain greases with required colloidal stability.

Tetraalkylammonium molybdenum and rhenium thiometallates with different alkyl groups have been synthesized. The compounds obtained have been characterized by spectral and thermal methods. By thermosolvolysis of tetraalkylammonium thiometallates at 155–165°С in a DMF medium, particles of MoS3 and Re2S7 sulfides soluble in nonpolar hydrocarbons owing to the treatment of their surface with surfactants (alkenylsuccinimide) have been prepared. The particle size of these sulfides ranges within 8–110 nm depending on the nature of the precursor. A high friction-reducing activity of molybdenum nanoparticles in a mineral lubricating oil medium and antiwear activity of rhenium nanoparticles in mineral and synthetic lubricating oils have been shown.

This article presents first results of the investigated physico-chemical and operational parameters of composition greases obtained with the use of esters of different nature as a dispersion medium and the polyurea as a thickening agent, including the addition of nanocellulose. The choice of the ester base for the production of greases is possible due, on the one hand, to good combination of the physico-chemical properties (high viscosity index, low volatility, high flash and ignition temperature, low pour point, good anti-wear properties). On the other hand, in the production of greases with good ecological characteristics biodegradability of its components is of great importance, which in this case is provided by the use of esters as an oil base and an organic thickener, nanocellulose, as a component of the polyurea dispersed phase. It has been shown that from the dicarboxylic acid esters studied, the polyurea greases based on dioctyl adipate are superior to the dropping point and better colloidal stability as compared to dioctyl sebacate and dibutyl sebacate. The smaller size of the ether molecule provides the stronger structure of the polyurea grease. Similarly, for branched ethers, the grease based on tri-basic alcohols is more effective than the four-basic alcohols. The possibility of using nanocellulose as a thickener component was demonstrated. An increase in the content of nanocellulose to 3.5% increases the colloidal stability and the dropping temperature of the synthesized greases. The obtained samples have a wider range of operating temperatures, better rheological indicators than imported and domestic analogues.

Quantum chemistry methods were used to calculate the energy parameters of an elementary unit and a cellulose macromolecule dimer (cellobiose), and structure simulation was performed and the energy of interaction between the fragments of native cellulose macromolecules was calculated. It was established that the trans conformation of cellobiose is more stable than the cis conformation by 6.7 kcal/mol. Differences in the calculated and real (according to literature data) IR spectra of cellulose were related to the presence of intramolecular and intermolecular hydrogen bonds in the native structure. It was shown that the interaction of individual fragments of cellulose macromolecules from eight monomer units is due to the manifestation of intramolecular hydrogen bonds. It was found that the energies of intermolecular interactions ∆Е essentially depend on the terminal groups X in the cellulose macromolecule fragments, and they are –26, 49, and ‒32 kcal/mol for X = –H, –COOH, and –COH, respectively. The structure of the interacting fragments of cellulose macromolecules can be regulated by replacing the hydrogen atoms of hydroxyl or terminal groups of the macromolecules with functional groups that do not form intramolecular hydrogen bonds and impede self-organization into fibrillar structures. It was shown that compounds with a high electron affinity or a negative energy of the lower vacant molecular orbital are the best reagents for complexation reactions with cellulose.

In the course of studying the dependence of wear properties on the composition of a mixture of hydrocarbon oils with polyorganosiloxanes, it has been revealed that adding 10 wt % hydrocarbon oils to polyorganosiloxane leads to significant growth in the diameter of the wear pot. A further increase in the content of hydrocarbon oils in the mixture at a concentration of ~30 wt % induces a sharp decrease in the wear parameter and it has a value lower than that for a clean oil. An analogous, but less expressed dependence for antiscuff properties has been observed. The values of density and viscosity of the mixtures in the same limits was detected. Based on element analysis, IR spectroscopy, and roentgen fluorescent analysis, the nature of the found effect has been proposed.