The carbonization temperature of carbon precursors before their activation is an important factor affecting the porous structure and properties of the resulting activated carbons. In this work сorrelation between the textural and adsorption properties of asphalt-based porous carbons and the carbonization temperature has been found. Additionally, the optimal carbonization temperature, and reasons why the carbonization temperature affects the main textural characteristics of the activated carbon were established. A series of porous carbons has been prepared from petroleum asphalt by a two-stage method, including carbonization of asphalt at different temperatures from 450 to 800 °C and KOH activation. To reveal the reasons of the correlation the carbonized samples were studied by TG-DTG, IR-Fourier, TEM methods. It is shown that the carbonization temperature effects on the structural defects, distance between the graphene layers, the reactivity and thermal stability of the carbonized asphalts. These specificities contribute to formation of porous structures of the activated carbons. The carbonization temperature 500–600 °С of the petroleum asphalt is found to be the optimal for further activation. The KOH activation of the petroleum asphalts carbonized at 500–600 °С provides microporous carbon with the high specific surface area (about 2000 m2g-1) and the CO2 uptake (3.3 mmolg-1). Additionally, the specific surface area of the activated carbons is shown can be predicted from the temperature of 50

The adsorption properties of a carbon sorbent in relation to sulfosalicylic acid in an individual solution and with an added amino acid (arginine or phenylalanine) were determined. It has been shown that the addition of arginine to an aqueous solution of sulfosalicylic acid leads to an increase in the amount of sulfosalicylic acid adsorbed on the carbon sorbent. The sorbents modified in the presence of amino acids showed high adsorption capacity for the methylene blue dye.

Single phase CuCoMgAl-layered hydroxides were obtained by making fine adjustment to their composition through changing the (Co + Cu)/Mg = 0.5; 1; 2; 3 and Co/Cu = 0.5; 1; 2 ratios. The rise of Co/Cu in systems contributed to the increase in their thermal stability. CuCoMgAl-catalysts showed high selectivity of carbonyl group hydrogenation in furfural and 5-hydroxymethylfurfural. In furfural hydrogenation, the selectivity to furfuryl alcohol was more than 99%, and in 5-hydroxymethylfurfural hydrogenation, the selectivity to 2,5-hydroxymethyl furfural was 95%. The surface of the samples with different Co/Cu after calcination and reduction was the same and had a «core-shell» structure (TEM). «Core» consisted of Cu and Co metallic particles. «Shell» consisted of CuCoMgAlOx mixed no-stoichiometric spinel oxides. There was no sintering or change in size of the metallic particles after the reaction. For the sample with Co/Cu = 1, their phase composition after reaction remained unchangeable. The increase of Co/Cu led to the formation of an X-ray amorphous phase after the reaction. This suggests the decrease in structural stability of this sample. The obtained results prove the prospects of using bimetallic CoCu-systems for hydrogenation of furan aldehydes, and opens up new directions for further research and improvement.

For the first time an advanced carbon sorbent modified with salicylic acid for medicinal and veterinary applications was synthesized by the adsorption from solutions. Optimal parameters of the modification were determined: Solvent, “carbon sorbent–modifier” ratio, concentration of salicylic acid, equilibration time of the process in the “sorbent–salicylic acid solution” system, pH, and process temperature. The effect of the drying parameters on stability and amount of oxygen-containing groups on the carbon sorbent surface after modification was established. Physicochemical properties of the carbon sorbent and sorbents modified with different concentrations of salicylic acid were investigated: textural characteristics, qualitative and quantitative compositions of the surface functional groups, and amount of the deposited modifier. The possibility of salicylic acid desorption into the media simulating biological fluids, particularly the gastrointestinal medium, was explored. Adsorption characteristics of the carbon sorbent and sorbents modified with different concentrations of salicylic acid with respect to organic dyes—methylene blue and metanil yellow in a wide range of operating concentrations—were revealed.

Thermal stability of carbon black (CB) functionalized with sodium benzenesulfonate groups in argon was studied using thermogravimetric and differential thermal analysis coupled with mass spectrometry, infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. Thermal analysis showed that decomposition of sulfonated CB is observed over the temperature ranges of 450-610 degrees C, which correspond to desulfonation. Physicochemical studies revealed that desulfonation was accompanied by decomposition and fragmentation of the sodium benzenesulfonate groups with the release of H2O, CO2 and SO2 as the main gaseous products and the formation of solid products Na2SO4 and Na2S.

Mechanochemical synthesis of MgAl-layered double hydroxides (MgAl-LDH) with molar ratio MgAl = 3 was performed. The effect of the acceleration of milling bodies (500 and 1000 m s(-2)), activation time (5-90 min), and water addition on the phase composition of obtained samples, their structural parameters, as well as on the process of formation of mixed oxides, prepared after LDH calcination was studied. The conditions for the preparation of single-phase LDH were established. It was shown the possibility of the textural properties regulation of mixed oxides by change of the mechanochemical synthesis parameters of corresponding layered double hydroxides. (C) 2021 Elsevier B.V. All rights reserved.

Catalysts based on CuAl-, CoAl-, and CuCoAl-layered hydroxides with M2+/Al = 2 and Cu/Co = 1 molar ratio were obtained. The effect of amount of cobalt on the structural properties, morphology, surface cations distribution, oxide phase formation, thermal stability of the samples and reduction of metals from them was studied. The effect of reaction conditions (temperature, time, pressure, solvent) and conditions of preliminary treatment of catalysts on their catalytic properties in furfural hydrogenation was established. High selectivity to furfuryl alcohol was observed for all the samples irrespective of pretreatment and reaction conditions. The synergetic effect in furfural hydrogenation between Co and Cu in the CuCoAlOx catalysts was revealed when ethanol is used as a solvent.

The analytical survey over the literature data and results of the studies carried out by the authors into the physicochemical characteristics and catalytic properties of highly dispersed massive polymetallic Ni-Mo-W and Ni-Mo catalysts, and carbide-containing Mo2C/C catalysts of the core - shell type is presented. Catalytic carbon systems in which the active centres are functional oxygen-containing surface groups are also considered. It is shown that all the catalytic objects under consideration may be successfully synthesized by means of mechanochemical activation.

Molybdenum carbide-based carbon materials were investigated as a catalyst for hydrodeoxygenation (HDO) of guaiacol. Mechanochemical synthesis has been used as a novel approach to obtain a fine molybdenum carbide-based carbon catalysts. Guaiacol was chosen as a bio-oil model compound to estimate the potential of the catalysts. The catalytic tests were carried out at 4 MPa initial hydrogen pressure, 320 degrees C for 180 min in a batch autoclave reactor. Insert abstract text here. A feed mixture was 3.5 g guaiacol in 66.5 g hexadecane as a solvent.

Рассмотрено применение катализаторов на основе карбида молибдена. Особое внимание уделено влиянию способа получения карбида молибдена на его кристаллическую структуру и каталитическую активность в окислительно-восстановительных реакциях органических соединений.

The applications of catalysts based on molybdenum carbide are considered. Attention is focused on the effects of molybdenum carbide preparation methods on the crystal structure and catalytic activity of molybdenum carbide in the redox reactions of organic compounds.

Scientific publications and patents on mechanochemical synthesis of inorganic supports and catalysts of oil refining processes (cracking, reforming, hydrotreating, and hydrocracking) were analyzed. It was shown that the introduction of mechanical activation into the process of synthesis of inorganic supports and catalysts typically enhances their catalytic activity and selectivity. Features of the mechanochemical synthesis of complex nickel-molybdenum oxides, which are precursors of nickel-molybdenum sulfide hydrotreating catalysts, were considered. It was demonstrated that, under mechanical activation conditions, it is possible to prepare β-NiMoO 4 , a highly active and thermostable nickel-molybdenum oxide containing Mo in tetrahedral coordination. The technology of producing highly dispersed carbide-containing catalysts with the use of the mechanical activation method, developed at the Institute of Hydrocarbon Processing, Siberian Branch, Russian Academy of Sciences, was described. The texture and morphology of the resultant highly dispersed bulk carbide-containing catalysts were considered. The size of the active particles was estimated at 2–5 nm. Сatalytic tests revealed high catalytic activity of the highly dispersed carbide-containing catalysts in the model reaction of dibenzothiophene hydrodesulfurization.

A method for synthesis of carbide containing composites by mechanical activation has been developed. A mixture of molybdenum oxide, carbon black and Al or Zn metal reductant have been treated for 15 min in air followed by a subsequent calcination in argon atmosphere at 800 degrees C. The elemental and phase composition, structure, texture and particle morphology of these composites were studied. Mechanically activated and calcined samples were found to contain 6.5 and 5.9% of the molybdenum carbide phase, respectively. (C) 2019 Elsevier B.V. All rights reserved.

Проведен анализ научных публикаций и патентов, посвященных механохимическому синтезу неорганических носителей и катализаторов нефтеперерабатывающих процессов: крекинга, риформинга, гидроочистки и гидрокрекинга. Показано, что введение механической активации в технологический процесс синтеза неорганических носителей и катализаторов, как правило, приводит к повышению каталитической активности и селективности. Рассмотрены особенности механохимического синтеза сложных никель-молибденовых оксидов, которые являются предшественниками сульфидных никель-молибденовых катализаторов гидроочистки. Показано, что в условиях механической активации возможно получение никель-молибденового высокоактивного и термостабильного β-NiMoO4, в составе которого Мо находится в тетраэдрической конформации. Описана разработанная в ИППУ СО РАН технология получения высокодисперсных карбидсодержащих катализаторов с применением метода механической активации. Рассмотрены текстура и морфология синтезированных высокодисперсных массивных карбидсодержащих катализаторов. Показано, что размер активных частиц составляет 2–5 нм. Проведены модельные каталитические испытания и установлено, что карбидсодержащие высокодисперсные катализаторы проявляют высокую каталитическую активность в модельной реакции гидрообессеривания дибензотиофена.

Mechanochemical activation was used to prepare Mg(Li)Al-layered double hydroxides (LDH) with molar ratios of cations Mg/Al = 2 and 4 and Li/Al = 0.5. The influence of cationic composition and nature of interlayer anions (CO32-, OH-) on the structural properties of LDH and the properties of oxide phases formed by LDH calcination was investigated by XRD and SEM. Textural properties (nitrogen adsorption-desorption isotherms at 77.4 K) and acid-base properties (CO2 double isotherm method, TPD-CO2, aldol condensation of furfural with acetone reaction) were studied in detail for mixed oxides. It was shown that mixed oxides based on the LDH that were prepared by mechanochemical route have high specific surface area and porosity. An increase in the Mg/Al ratio, the introduction of Li, and the use of LDH with OH- counterions made it possible not only to increase the total basicity of mixed oxides but also to vary the fraction of basic sites with a different strength.

MgAl-, NiAl-, CoAl and LiAl-layered double hydroxides (LDH) were prepared by mechanochemical method. The conditions of mechanochemical synthesis of the single phase LDH with specified composition were optimized. It was shown that application of the steel milling bodies allowed carrying out of the synthesis in the most severe conditions (acceleration 1000 m s(-2), time of activation 30 minutes) and promoted deeper reaction between initial components. It was found that for the synthesis of single-phase MgAl-, NiAl-and CoAl-LDH, the corresponding metal hydroxides and sodium carbonate should be used, and to obtain LiAl-LDH, aluminum hydroxide and lithium nitrate should be selected as initial reagents.

A technology has been developed for producing porous carbon materials in the form of granules with a diameter of 0.5-0.8 mm with a micro-mesoporous texture. An aqueous solution of furfuryl alcohol was used as a dispersion medium, followed by heat treatment in inert, hydrocarbon and oxidizing atmosphere for the development of a microporous texture at the granule formation stage using the granulation and extrusion methods of carbon black. A technology has been developed for modifying the texture of a mesoporous carbon material in the form of honeycomb blocks, which ensures the production of a carbon sorbent with a uniformly microporous texture. The technology consists of the impregnation of mesoporous Sibunit by furfuryl alcohol solutions in water, followed by polymerization and carbonization of the applied layer. Polymerization of FA and carbonization occur in the largest pores of the carbon matrix (30-50 nm), which act as nanoreactors. This leads to the formation of a uniform microporous structure with a pore size of 3-5 nm. It is shown, a modified Sibunit with a homogeneous microporous texture has molecular sieve properties in separating a mixture of gases CO2 + CH4.

A technology has been developed for modifying carbon black of industrial and special brands when conducting mechanical activation of technical conditions in an oxidizing environment. The technology of mechano-chemical synthesis of carbide-containing composite has been developed. The formulation of mechanically activated mixture, the parameters of mechano-chemical synthesis and calcination conditions were established, which provide for the production of carbide-containing composites, the molybdenum carbide phase is well crystallized and the amount of impurities is minimal.

Fine molybdenum-carbide catalytic systems were obtained by the method of mechanical activation in an inert atmosphere.The composition and morphology were investigated, the catalytic behavior of molybdenum-carbide systems was estimated in the hydrotreatment process of vacuum residue.In the presence of a molybdenum-carbide catalyst, a decrease in the coke yield by more than three times is observed compared to the coke content obtained with the same temperature-time parameters of the process without a catalyst.