This paper presents methods for the production of nanoscale coke powders for bitumen modification. The chemical vapor deposition (CVD) method enables the production of nanopowders with particle sizes ranging from 14 to 30 nm at temperatures of 1000–1200 oC. Bitumen modification was performed by adding nanoscale coke powders, in accordance with the requirements of Kazakhstan standard 1373–2013. The nanosized powders were obtained by CVD in an inert nitrogen atmosphere with a specific surface area of 24.8 m2/g. Modification of bitumen with nanoscale coke yields grades with high thermal stability, ensuring optimal structural strength and durability of the pavement. Rheological studies show that nanoscale coke acts as an active structure-forming agent rather than an inert filler. The restriction of asphaltene mobility leads to a consistently reduced phase angle (δ) and the absence of a transition to a viscosity-dominated regime. The samples are characterized by the lowest phase angle values across the entire range of the complex modulus. This indicates the formation of a highly developed elastic-viscous structure due to the presence of nanosized coke, which promotes the formation of a percolating physical network and restricts the mobility of the bituminous system. The observed behavior indicates the dominance of the elastic component and the increased structural organization of the resulting bituminous binders.
Coordination compounds of Cu(II) ions with some oxyphosphonates were synthesized in ethanol using ultrasonic activation. The complexes were isolated as blue crystalline powders in yields of 72–87%. Complex formation was confirmed by IR spectroscopy and thermal analysis. The shift of the ν(P=O) band to lower frequencies indicates the involvement of the phosphoryl oxygen in coordination with the Cu(II) ion. Changes in melting points compared to the initial ligands indicates a rearrangement of the crystal structure. For the piperidine based complex, the N,O coordination type was observed by the appearance of a Cu–N absorption band at 661 cm⁻1. The biological activity of the synthesized compounds was evaluated using a wheat seed germination model. It was found that the oxyphosphonates and their complexes stimulate seedling development, leading to increased shoot and root lengths compared to the control. The most pronounced effect was observed for compounds containing phenyl and piperidine moieties, with root length increases reaching 74.8% and shoot length by 18.7%, relative to the control. In addition, the copper complexes suppressed the growth of mold microflora on treated seeds, exhibiting antimicrobial activity. These results demonstrate the potential of phosphorus-containing Cu(II) coordination compounds as potential agrochemicals with growth-promoting and antimicrobial properties.
The formation of hydrogen fluoride (HF) during the auto-ignition process of stoichiometric difluoromethane (R32)-air mixtures is numerically investigated in a cylindrical vessel under the influence of heat losses and heterogeneous wall reactions. Both slow reaction and successful explosion regimes are analyzed to study the thermo-kinetic conditions leading to HF formation. A detailed chemical mechanism is used for the gas-phase chemistry, while heterogeneous destruction reactions of reactive species at the wall surface are additionally considered. The effects of initial temperature, pressure and surface destruction efficiencies on HF production are investigated. Particular attention is paid to the role of OH radicals and heterogeneous wall reactions in controlling the formation of HF under non-explosive conditions.
This review article systematizes current knowledge on the catalytic hydrogenation of benzene as a key process in petrochemistry, environmental protection, and hydrogen energy technologies. The fundamental mechanisms of benzene ring activation and molecular hydrogen dissociation on transition metal surfaces are discussed, with particular emphasis on the disruption of aromatic stability as the rate-limiting step of the reaction. Special attention is given to the challenge of achieving selective benzene hydrogenation in the presence of other aromatic compounds, a situation typical of reformate and pyrolysis gasoline fractions. The influence of the active metal type (Ni, Pd, Pt, Ru), catalyst supports (oxide, zeolitic, carbon-based, and natural materials), and reaction parameters (phase, temperature, and hydrogen pressure) on catalytic activity, selectivity, and stability is systematically analyzed. Competitive adsorption among aromatic compounds, the role of electronic and steric effects of substituents, and mass-transfer limitations in liquid-phase systems are also examined. Results obtained for both industrial and emerging catalytic systems are summarized, including catalysts for the deep and partial hydrogenation of benzene, as well as their potential applications in liquid organic hydrogen carrier (LOHC) technologies. Achieving high selectivity therefore requires comprehensive optimization of catalyst composition, support structure, and process conditions, which defines the main directions for future research.
The paper presents the synthesis of a solid hydrocomposite material in a water-glycerol medium based on [MoO4]2–, Zr4+, Er3+, and Na ions in a 1:1:1:3 molar ratio using directional mixing of solutions in a U-shaped vessel. X-ray diffraction analysis confirmed the partially amorphous structure of the synthesized product. Infrared spectroscopy revealed the presence of bound water molecules and characteristic functional groups, including hydroxyl, aliphatic, and metal-hydroxide fragments, as well as bands characteristic of [MoO4]2– ions. Elemental and atomic emission analyses confirmed the presence of all the initial ions and revealed the molar ratio of the elements. X-ray microanalysis demonstrated chemical heterogeneity of the solid phase, while electron microscopy revealed an overall morphological homogeneity of the particles. Investigation of the luminescent properties showed the superposition of several peaks in the visible spectrum associated with transitions in the 4f shell of erbium ions, indicating the material's potential for applications in biomedicine, sensors, and optoelectronics. Thermal analysis further confirmed the presence of chemically bonded water molecules. The obtained results provide a basis for further investigation and targeted modification of the properties of such hydrocomposite systems.
