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An environmentally friendly and safe synthesis of phloroglucinol and its derivatives through the flow hydrogenation of 1,3,5-trinitrobenzenes on heterogeneous copper catalysts is reported. It was found that hydrogenation of 1,3,5-trinitrobenzene, 2,4,6-trinitrotoluene, 2,4,6-trinitroxylene, and 2,4,6-trinitromesitylene in methanol over Cu–Al mixed oxides derived from layered double hydroxides led to selective formation of the corresponding triaminobenzenes, which were isolated from the reaction mixture in the form of double salts with sulfuric acid and were stable in storage. Subsequent hydrolysis in aqueous solution gave the phloroglucinol derivatives in good yields (75–82%).

Ni-phosphides present a promising alternative to the conventional hydrotreatment NiMo sulfides. The hydrotreatment catalysts are supported on Al2O3 granules, and the similarly Al2O3 supported Ni-phosphide catalysts provide an interesting case for comparison. In this work the Ni-phosphide catalysts supported on Al2O3 granules were prepared using two procedures: 1) temperature-programmed reduction of “phosphite”-type precursor in hydrogen flow (TPR_I catalyst), 2) treatment of Ni nanoparticles with triphenylphosphine solution at elevated temperature (LP catalyst). The catalysts were characterized by ICP-AES chemical analysis, N2 physisorption, XRD, TEM, XPS, 27Al MAS NMR. The Ni2P particles were found in LP samples, while TPR method gives the mixture of Ni12P5 and Ni2P particles and amorphous AlPO4 on the alumina surface. The behavior of granulated Ni phosphide and conventional sulfided NiMo/Al2O3 catalysts was compared in hydroprocessing of straight-run gas oil (SRGO) at 340 °C, 4 MPa, V(H2)/V(feed) - 400 Nm3/m3, LHSV - 1,5 h−1. Hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activity of nickel phosphide catalysts were shown to be lower in comparison with NiMo/Al2O3. Hydrotreating of S-containing model compounds (DBT, 4-MDBT, 4,6-DMDBT) was carried out over TPR_I catalyst, and a negative effect of dimethyl disulfide (DMDS) and acridin additions on the HDS activity was observed.

Co-processing of mixture, containing 30 wt.% of rapeseed oil (RSO) in straight run gas oil (SRGO), was studied over stacked bed sulfide catalytic system containing Mo/Al2O3 as a first layer and CoMo/Al2O3-SAPO-11 or NiMo/Al2O3-SAPO-11 catalyst as the second one. The experiments were performed in a trickle bed reactor at 350−380 °C, 4.0–7.0 MPa, 1.5 h−1 and 1000 Nm3/m3. The hydrodeoxygenation (HDO) of RSO is proceeding over Mo/Al2O3 catalyst mostly through direct HDO route (selectivity > 93 %). The proposed combination of catalysts minimizes the formation of carbon monoxide, that is known as an inhibitor of hydrotreating reactions and can affect the hydroisomerisation/hydrocraking of alkanes over CoMo/Al2O3-SAPO-11 and NiMo/Al2O3-SAPO-11 catalysts. The effects of temperature and pressure on the behavior of Mo/Al2O3-CoMo/Al2O3-SAPO-11 and Mo/Al2O3-NiMo/Al2O3-SAPO-11 systems were studied and the difference in the quality of products were discussed with the emphasis on the cold flow properties. The cloud point of products, obtained in the co-processing of RSO-SRGO mixture over Mo/Al2O3-CoMo/Al2O3-SAP and Mo/Al2O3-NiMo/Al2O3-SAP catalytic systems was decreased to −8 and −13 °C respectively with the temperature increase from 350 to 380 °C. In addition, the hydrogenated products produced over NiMo/Al2O3-SAP were characterized by lower final boiling point values and aromatic content in comparison with that produced over CoMo/Al2O3-SAP catalyst. Unexpectedly, the opposite effect of pressure was observed on the cloud point and the conversion of long chain alkanes, which were produced in hydrodeoxygenation of RSO.

Cu-containing layered double hydroxides (LDHs) were synthesized by a co-precipitation method at different reaction conditions, such as aging time, pH, precipitation rate and synthesis temperature. The effect of these parameters on the structure and chemical composition of the catalysts were investigated using a set of physical methods, including thermogravimetric analysis (TGA), X-ray diffraction (XRD), H2-TPR and in situ X-ray photoelectron spectroscopy (XPS). It allowed for checking of the reducibility of the samples. 5-Acetoxymethylfurfural was catalytically hydrogenated to 5-(acetoxymethyl)-2-furanmethanol (AMFM) over Cu-containing catalysts synthesized from layered double hydroxides so as to investigate its catalytic properties in flow reaction. It was shown that synthesis pH decreasing from 10 to 8 resulted in rise of AMF conversion that coincided with the higher surface Cu/Al ratio obtained by XPS. Preferable aging time of LDH materials for obtaining the most active catalyst was 2 h, an amount of time that favored the production of the catalyst with high surface Cu/Al ratio up to 0.38. Under optimized reaction conditions, the AMFM yield was 98%. Finally, a synthesis strategy for the preparation of highly efficient Cu-based hydrogenation catalyst with optimized characteristics is suggested.

BACKGROUND: Secondary amines are important intermediates in the manufacture of pharmaceuticals and other valuable chemicals. Hence, there is a continuing interest in cost‐effective and environmentally friendly methods for producing these compounds. Reductive amination of aldehydes or ketones with primary amines over heterogeneous metal catalysts is an attractive approach due to the use of inexpensive and environmentally benign molecular hydrogen as a reducing agent. RESULTS: Various secondary amines were obtained by two‐step reductive amination of benzaldehyde derivatives and furfural with primary amines. The condensation of aromatic aldehydes with amines at room temperature in low water methanol gives imines, which are then hydrogenated in a flow reactor over CuAlOₓ catalyst derived from layered double hydroxide. This process does not require isolation and purification of intermediate imines and can be utilized to obtain several secondary amines in good to excellent yield. The time‐dependent study showed that CuAlOₓ catalyst demonstrates excellent stability in imine hydrogenation. CONCLUSION: An environmentally friendly procedure has been developed for the synthesis of secondary amines through a reductive amination of aromatic aldehydes with primary amines over Cu‐based catalyst. This procedure presents a novel way for the sustainable production of secondary amines. © 2020 Society of Chemical Industry

A high dispersion and low degree of crystallinity of supported MoS2 nanoparticles have almost excluded conventional X-ray diffraction (XRD) analysis from a range of physical methods for characteriz...

Levulinic acid and its esters (e.g., ethyl levulinate, EL) are platform chemicals derived from biomass feedstocks that can be converted to a variety of valuable compounds. Reductive amination of levulinates with primary amines and H2 over heterogeneous catalysts is an attractive method for the synthesis of N-alkyl-5-methyl-2-pyrrolidones, which are an environmentally friendly alternative to the common solvent N-methyl-2-pyrrolidone (NMP). In the present work, the catalytic properties of the different nickel phosphide catalysts supported on SiO2 and Al2O3 were studied in a reductive amination of EL with n-hexylamine to N-hexyl-5-methyl-2-pyrrolidone (HMP) in a flow reactor. The influence of the phosphorus precursor, reduction temperature, reactant ratio, and addition of acidic diluters on the catalyst performance was investigated. The Ni2P/SiO2 catalyst prepared using (NH4)2HPO4 and reduced at 600 °C provides the highest HMP yield, which reaches 98%. Although the presence of acid sites and a sufficient hydrogenating ability are important factors determining the pyrrolidone yield, the selectivity also depends on the specific features of EL adsorption on active catalytic sites.

Behavior of the sulfide NiMo catalyst on an alumina support containing SAPO—11 silicoaluminophosphate (NiMo/SAP-Al2O3) in the hydroprocessing of a mixture of a straight run gas oil (SRGO) and rapeseed oil (RO) was studied under a pressure of 5.0 MPa and liquid hourly space velocity of 1.5 h−1. The effect of temperature on the properties of the products produced in the hydroprocessing of a mixture with 30 wt % RO and 70 wt % SRGO in the presence of the NiMo/SAP-Al2O3 catalyst and a double-bed catalytic system containing layer-by-layer loaded Mo/Al2O3 and NiMo/SAP-Al2O3 sulfide catalysts. It was found that the experimental conditions provide a full conversion of oxygen-containing compounds and reduction of the content of sulfur to less than 10 mg kg−1. Raising the temperature from 330 to 380°C leads to an increase in the conversion of alkanes formed due to the hydrodeoxygenation of rapeseed oil and to lowering of the cloud point of the hydroprocessing products by approximately 15°. Possible reasons for the differences in behavior between the systems under study: a high conversion of C17, C18 alkanes is reached in the presence of the NiMo/SAP-Al2O3 catalyst, whereas the double layer Mo/Al2O3 + NiMo/SAP-Al2O3 system provides a more effective course of the reactions in which aromatic hydrocarbons are hydrogenated.

Behavior of the CoMo/Al2O3 catalyst was experimentally studied in the course of hydrotreating of a straight-run gas oil with high content of sulfur (>2 wt %) and its mixture (up to 30 wt %) with light coker gas oil in the temperature range 335–365°C and liquid hour space velocity of feedstock deliver of 0.8–2.5 h−1. It was shown that addition of gas oil to the straight-run gas oil in hydrotreating under the conditions corresponding to the working conditions of the existing domestic hydrotreating installations [L-24-5, L-24-6, L(Ch)-24-7] has oppositely directed effects, depending on temperature and feedstock delivery rate. For example, the additives lead in the temperature range 335–350°C to an increase in the content of sulfur in hydrotreating products. At a temperature of 365°C, better sulfur-related parameters are reached in processing of feedstocks containing light coker gas oil. The observed dependences are accounted for as follows: the dilution of the straight-run gas oil by addition of light coker gas oil leads to a decrease in the content of difficulty converted sulfur-containing compounds, but makes larger the content of nitrogen-containing compounds inhibitors of the hydrodesulfurization reaction, the influence of which on the reaction rate becomes weaker with increasing temperature.

The effect of ethylene glycol (EG), diethylene glycol (DEG), and triethylene glycol (TEG) on the sulfidation behavior of phosphate-doped NiMo/Al2O3 hydrotreating catalysts has been investigated. The catalyst prepared with DEG shows a higher activity in the hydrodesulphurization of straight-run gas oil than other catalysts due to more efficient sulfidation at the low-temperature stage.

BACKGROUND: The search for alternative sources of fuels is crucial for sustainable development now and in the near future. Biomass attracts much attention as an environmentally friendly, green and CO₂‐neutral source of fuels. Hydrodeoxygenation (HDO) of fatty acid‐based feedstocks such as nonedible vegetable oil, waste cooking oil and animal fat is a versatile technology for producing efficient fuels. HDO schemes are often contradictory and have different numbers of stages. In the work reported, a highly active nickel phosphide catalyst was obtained and methyl palmitate (MP) HDO kinetic modelling was carried out to elucidate the HDO reaction scheme. RESULTS: The effect of reduction temperature (400–600 °C) on the catalytic properties of the catalyst in MP HDO was evaluated and the most active catalyst (after reduction at 450 °C) was used in the kinetic experiments. The experimental data were collected in a wide range of MP conversion. The reaction scheme of MP HDO was elucidated by means of mathematical modelling which was specified by successive consideration of the experimental results of HDO selectivities at low MP conversions (1–10%), additional experiments of alcohol HDO (dodecanol‐1 as an analogue for hexadecanol‐1) and analysis of gas‐phase products. CONCLUSIONS: In accordance with the results obtained, both hydrolysis of MP and hydrogenolysis of CbOCH₃ bond should be considered for describing the conversion of MP to intermediate compounds. This finding could explain the synergetic effect of acid and metal centres, which has been reported in the literature on aliphatic ester HDO, and justify the higher activity of bifunctional catalysts in this reaction. © 2019 Society of Chemical Industry

The trivalent iron oxide e-Fe2O3 is a fairly rare polymorphic iron oxide modification, which only exists in the form of nanoparticles. This magnetically ordered material exhibits an intriguing magnetic behavior, specifically, a significant room-temperature coercivity HC (up to ~20 kOe) and a magnetic transition in the temperature range of 80–150 K accompanied by a sharp decrease in the HC value. Previously, the temperature of the transition to the paramagnetic state for e-Fe2O3 was believed to be about 500 K. However, recent investigations have shown that the magnetically ordered phase exists in e-Fe2O3 also at higher temperatures and, around 500 K, another magnetic transition occurs. Using the data on the magnetization and temperature evolution of the ferromagnetic resonance spectra, it is shown that the temperature of the transition of e-Fe2O3 particles 3–10 nm in size to the paramagnetic state is ~850 K.

Ni-phosphide catalysts on SAPO-11 were studied in the hydrodeoxygenation–isomerization of methyl palmitate (C15H31COOCH3—MP). The catalysts were synthesized using temperature-programmed reduction (TPR) of a phosphate precursor ((NH4)2HPO4 and Ni(CH3CH2COO)2), TPR of a phosphite precursor (H3PO3 and Ni(OH)2), and using phosphidation of Ni/SAPO-11 by PPh3 in the liquid phase. The samples were characterized by ICP-AES chemical analysis, N2 physisorption, NH3-TPD, XRD, and TEM. First, the screening of the catalysts prepared by the TPR method was carried out in a semi-batch autoclave to determine the influence of the preparation method and conditions on one-pot HDO–isomerization (290–380 °C, 2–3 MPa). The precursor’s nature and the amount of phosphorus strongly influenced the activity of the catalysts and their surface area and acidity. Isomerization occurred only at a low P content (Ni/P = 2/1) and blocking of the SAPO-11 channels by unreduced phosphates at higher P contents did not allow us to obtain iso-alkanes. Experiments with liquid phosphidation samples in a continuous-flow reactor also showed the strong dependence of activity on phosphidation duration as well as on Ni content. The highest yield of isomerized products (66% iso-C15–16 hydrocarbons, at complete conversion of O-containing compounds, 340 °C, 2 MPa, and LHSV = 5.3 h−1) was obtained over 7% Ni2P/SAPO-11 prepared by the liquid phosphidation method.

The stability of a catalyst for partial H2S oxidation has been studied by the ferromagnetic resonance (FMR) technique combined with transmission electron microscopy, X-ray diffraction, Mossbauer spectroscopy, and magnetostatic investigations. The e-Fe2O3 iron oxide nanoparticles supported on silica have been examined for their stability under the selective H2S oxidation conditions. The combination of the physicochemical methods has been used to study the state of reacted catalysts. The e-Fe2O3 phase has been found to remain stable under the selective H2S oxidation conditions at temperatures up to 300 °C. The active phase state during the catalytic reaction has been explored using in situ FMR experiments. It has been established that the e-Fe2O3 nanoparticles retain their structure and magnetic properties in the presence of H2S at high temperatures. During the in situ FMR experiments, the e-Fe2O3 sulfidation process has been studied.

Patents dealing with the production of motor fuel components by hydrodeoxygenation of renewable raw materials based on fatty acid triglycerides are analyzed. Various methods of using sulfide catalysts in hydrodeoxygenation of fatty acid triglycerides and of their mixtures with petroleum fractions are described. The ways to overcome problems that arise in hydrodeoxygenation, based on using sulfide catalysts differing in the active component and support composition, are considered. For example, the use of supported MoS2 catalysts free of Co and Ni ensures the conversion of fatty acid triglycerides along the “direct hydrodeoxygenation” pathway to avoid the formation of carbon oxides and related process problems. The use of sulfide catalysts on zeolite-containing supports allows synthesis of products with improved low-temperature properties due to isomerization (or mild hydrocracking) of С15–С18 alkanes formed by hydrodeoxygenation of fatty acid triglycerides.

The effect of the support on the properties of copper catalysts supported on γ-Al2O3, SiO2, and TiO2–SiO2 with a ~5 wt % Cu content was studied in the one-pot synthesis of N-heptyl-p-toluidine from p-nitrotoluene and n-heptanal. The catalysts were characterized by elemental analysis, X-ray diffraction analysis, transmission electron microscopy, temperature-programmed reduction, and low-temperature nitrogen adsorption. The reaction was carried out in a flow reactor with the use of molecular hydrogen as a reducing agent. It was established that the nature of the support exerts a profound effect on the yield of the target secondary amine; in this case, 5%Cu/Al2O3 was found the most active catalyst. A combination of high catalyst activity in the hydrogenation of a nitro group to an amino group with the presence of acid sites, which facilitate imine formation as a result of the interaction of n-heptanal with p-toluidine, on the catalyst surface is necessary for reaching the greatest yield of N-heptyl-p-toluidine. The study of reaction mechanism on the 5%Cu/Al2O3 catalyst showed that p-nitrotoluene inhibits the hydrogenation of n-heptanal, and aldehyde hydrogenation into alcohol begins only after the conversion of the major portion of p-nitrotoluene as a result of the selective adsorption of the nitroarene under the conditions of the simultaneous presence of p-nitrotoluene and n-heptanal in the reaction mixture.

Hydrogenation of 3-nitrostyrene in a flow reactor over silver nanoparticles on TiO2-modified silica affords 3-vinylaniline with selectivity of 97% at the full conversion of the substrate.

N-alkyl-5-methyl-2-pyrrolidones are an attractive alternative to the common solvent N-methyl-2-pyrrolidone (NMP) and can be used as starting materials for synthesis of various valuable chemicals. Reductive amination of alkyl levulinates derived from biomass feedstock is a promising method for production of these compounds. In the present work, N-alkyl-5-methyl-2-pyrrolidones were obtained in excellent yields by reductive amination of ethyl levulinate with alkylamines over SiO2-supported nickel phosphide in a flow reactor using molecular hydrogen as a reducing agent. At the same time, aromatic amines and 1-nitropropane give a lower yield of the corresponding pyrrolidones. The influence of the solvent nature, temperature, pressure, hydrogen and liquid flow rates on the catalyst performance was studied.

Supported copper catalysts were investigated for the one-pot reductive amination of aldehydes with nitroarenes in a continuous flow reactor. This process is considered advantageous compared to current traditional methods, which present several drawbacks, such as toxicity of reducing or alkylation agent, lack of monoalkylation selectivity and large amounts of waste produced. Various secondary amines were synthesized in good to excellent yields in the reactions of aliphatic aldehydes with nitroarenes using molecular hydrogen as a reducing agent. It was found that the yield of secondary amine depends on the rate of formation of intermediate imine.

A dual-bed catalytic system including MoS2/Al2O3 and Co–MoS2/Al2O3 catalysts is proposed for the process of production of diesel fuel with the sulfur content of less than 10 ppm from a straight-run diesel fraction containing 10–45 wt % rapeseed oil. The conversion of rapeseed oil to alkanes proceeds in the MoS2/Al2O3 catalyst bed via the route of “direct” hydrodeoxygenation without the formation of carbon oxides, and the hydrodesulfurization of the diesel fraction occurs in the bed of the Co–MoS2/Al2O3 hydrotreating catalyst. Using this system provides an increase in the yield of diesel fuel and a decrease in the formation of greenhouse gases in comparison with conventional Co(Ni)–MoS2/Al2O3 catalysts.

Evolution of the local environment of Fe3+ ions in deposited Fe2O3/SiO2 nanoparticles formed in samples with different iron contents was investigated in order to establish the conditions for obtaining the stable e-Fe2O3/SiO2 samples without impurities of other iron oxide polymorphs. Microstructure of the samples with an iron content of up to 16% is studied by high-resolution transmission electron microscopy, X-ray diffraction analysis, and Mossbauer spectroscopy, and their magnetic properties are examined. At iron concentrations below 6%, calcinations of iron-containing precursor nanoparticles in a silica gel matrix lead to the formation of the e-Fe2O3 iron oxide polymorphic modification without foreign phase impurities, while at the iron concentration in the range of 6–12%, the hematite phase forms in the sample in the fraction of no more than 5%. It is concluded on the basis of the data obtained that the spatial stabilization of iron-containing particles is one of the main factors facilitating the formation of the e-Fe2O3 phase in a silica gel matrix without other iron oxide polymorphs. It is demonstrated that the increase in the iron content leads to the formation of larger particles in the sample and gradual changes of the Fe3+ ion local environment during the phase transition e-Fe2O3 → α-Fe2O3.

It is proposed that the sulfide NiMo system supported on alumina-SAPO-31 composite (NiMo/Al2O3-SAP catalyst) be used to obtain high-quality diesel fuel from a mixture of straight run diesel (SRGO) and light cycle oil (LCO) produced by fluid catalytic cracking (FCC). It is shown that the use of this catalyst ensures the synthesis of diesel fuel of higher quality upon hydroprocessing a feedstock with 30 wt % LCO, compared to the traditional sulfide NiMo/Al2O3 or CoMo/Al2O3 catalysts. It is found that the content of aliphatic hydrocarbons is raised in the products of hydrotreatment, compared to the initial feedstock. This confirms the ability of NiMo/Al2O3-SAP catalyst to facilitate the reaction of ring opening. Using the proposed catalyst should improve the quality of diesel fuels obtained via the hydroprocessing of LCO-containing feedstock.

HKUST-1@silica aerogel composite pellets (HKUST-1@SiO2) were prepared by the coupled sol–gel and water-in-oil emulsion method using supercritical CO2 drying. The structure and morphology of HKUST-1@SiO2 were characterized by X-Ray diffraction, scanning electron microscopy and low-temperature nitrogen adsorption. According to these data, the composite represents physically dispersed micron-sized domains of HKUST-1 in the silica aerogel pellets. It was shown that the HKUST-1@SiO2 pellets can be used as a catalyst for isomerization of styrene oxide to phenyl acetaldehyde in a continuous flow reactor.

Catalytic properties of physical mixture of MoP/SiO2 catalyst with SiC, &gamma, Al2O3, SAPO-11 and zeolite &beta, have been compared in hydrodeoxygenation of methyl palmitate (MP). MoP/SiO2 catalyst (11.5 wt% of Mo, Mo/P = 1) was synthesized using TPR method and characterized with N2 physisorption, elemental analysis, H2-TPR, XRD and TEM. Trickle-bed reactor was used for catalytic properties investigation at hydrogen pressure of 3 MPa, and 290 &deg, C. The conversions of MP and overall oxygen-containing compounds have been increased significantly (from 59 to about 100%) when &gamma, Al2O3 or zeolite materials were used instead of inert SiC. MP can be converted to palmitic acid through acid-catalyzed hydrolysis along with metal-catalyzed hydrogenolysis, and as a consequence the addition of material possessing acid sites to MoP/SiO2 catalyst could lead to acceleration of MP hydrodeoxygenation through acid-catalyzed reactions. Isomerization and cracking of alkane were observed over the physical mixture of MoP/SiO2 with zeolites, but the selectivity of MP conversion trough the HDO reaction route is remained on the high level exceeding 90%.

For the first time, we report the results of the study of dynamics of the Au/Al2O3 catalyst deactivation during the selective liquid-phase 3-nitrostyrene (3-NS) hydrogenation in a fixed bed flow reactor. It is shown that the formation of carbonaceous deposits is the main reason of catalyst deactivation, while the leaching of gold from the Au/Al2O3 catalyst or enlargement of the gold particles has not been detected. The content of the carbon deposits on the spent catalyst at the inlet of the reactor is higher than at the outlet and increases as the initial concentration of 3-NS grows. The character of carbonaceous deposits allocation and analysis of reaction products point out to 3-vinylnitrosobenzene as the main source of the Au/Al2O3 catalyst deactivation coinciding with the speculation arising from the kinetic modeling.

An alumina-supported silver catalyst was investigated in the one-pot reductive amination of aldehydes with nitroarenes in a continuous flow reactor using molecular hydrogen as a reducing agent. A series of secondary amines containing alkyl, OH, OCH3, Cl, Br and CC groups was synthesized in good to excellent yields. The yield of the secondary amine depends on the rate of formation of an intermediate imine. It was shown that the accumulation of carbonaceous deposits on the catalyst is the main reason of catalyst deactivation. The spent catalyst can be easily regenerated and reused without losing catalytic activity.

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала. We report the results of investigations of ε-Fe2O3 magnetic nanoparticles obtained by incipient wetness impregnation of silica gel. It was established that the obtained samples with an iron content of 12‒16% mass % containing ε-Fe2O3 nanoparticles with an average size of 10 nm on the silica gel surface exhibit a room-temperature coercivity of about 10 kOe. Along with fabrication simplicity, this fact makes the prepared samples promising for application as a magnetically hard material.

Aminomethylhydroxymethylfuran derivatives are well known for their pharmaceutical activities. In this work, the two-step one-pot procedure for the synthesis of N-substituted 5-(acetoxymethyl)-2-furfuryl amines was proposed, which includes two successive reactions: the condensation of 5-acetoxymethylfurfural (AMF) with primary amines and the reduction of obtained imines with hydrogen over supported metal catalysts in a flow reactor. The comparison of the properties of Au, Pd and Pt catalysts in the hydrogenation of imine obtained by reaction of AMF with aniline showed that Pt-based catalysts (both Pt/Al2O3 and Pt/C) are highly active and provide high selectivity and stability, while Pd and Au nanoparticles supported on γ-alumina and carbon show low selectivity. A wide range of N-substituted 5-(acetoxymethyl)-2-furfuryl amines was synthesized in good to excellent yields using Pt/Al2O3 catalyst and methanol as a solvent.

The effect of glycols on the catalytic properties of phosphate-doped NiMo/Al2O3 catalysts in the hydrotreating of straight-run gas oil (SRGO) was studied. The NiMo(P)/Al2O3 catalysts were prepared using ethylene glycol (EG), diethylene glycol (DEG), and triethylene glycol (TEG) as additives. The organic agent was introduced into the aqueous impregnation solution obtained by the dissolving of MoO3 in H3PO4 solution, followed by Ni(OH)2 addition. The Raman and UV&ndash, Vis studies show that the impregnation solution contains diphosphopentamolybdate HxP2Mo5O23(6&minus, x)&minus, and Ni(H2O)62+, and that these ions are not affected by the presence of glycols. When the impregnation solution comes in contact with the &gamma, Al2O3 surface, HxP2Mo5O23(6&minus, is decomposed completely. The catalysts were characterized by Raman spectroscopy, low-temperature N2 adsorption, X-ray photoelectron spectroscopy, and transmission electron microscopy. It is shown that the sulfide catalysts prepared with glycols display higher activity in the hydrotreating of straight-run gas oil than the NiMoP/Al2O3 catalyst prepared without the additive. The hydrodesulfurization and hydrodenitrogenation activities depend on the glycol type and are decreased in the following order: NiMoP-DEG/Al2O3 &gt, NiMoP-EG/Al2O3 &gt, NiMoP-TEG/Al2O3 &gt, NiMoP/Al2O3. The higher activity of NiMoP-DEG/Al2O3 can be explained with the higher dispersion of molybdenum on the surface of the catalyst in the sulfide state.

The effect of support nature, SiO2 and &gamma, Al2O3, on physicochemical and catalytic properties of nickel phosphide catalysts in methyl palmitate hydrodeoxygenation (HDO) has been considered. Firstly, alumina-supported nickel phosphide catalysts prepared by temperature-programmed reduction method starting from different precursors (phosphate&ndash, Ni(NO3)2 and (NH4)2HPO4 or phosphite&ndash, Ni(OH)2 and H3PO3) were compared using elemental analysis, N2 physisorption, H2-TPR, XRD, TEM, NH3-TPD, 27Al and 31P MAS NMR techniques and catalytic experiments. The mixture of nickel phosphide phases was produced from phosphate precursor on alumina while using of phosphite precursor provides Ni2P formation with the higher activity in methyl palmitate HDO. Besides, the comparative study of the performances of Ni2P/SiO2 and Ni2P/Al2O3 catalysts demonstrates the apparent superiority of alumina-supported Ni2P in the methyl palmitate hydrodeoxygenation. Considering the tentative scheme of methyl palmitate transformation, we proposed that cooperation of Ni2P and acid sites on the surface of alumina provides the enhanced activity of alumina-supported Ni2P through the acceleration of acid-catalysed hydrolysis.

Patent information on methods used for preparing catalytic systems containing molybdenum and tungsten phosphides and employing these systems in the hydroisomerization of paraffinic hydrocarbons are analyzed. Analysis of the patent information shows that modifying acidic supports with molybdenum and tungsten phosphides allows us to create a catalyst for the hydroisomerization of paraffinic fractions that is stable and resistant to sulfur impurities contained in the hydroisomerization feedstock.

The effect of phosphorus precursor on the physicochemical and catalytic properties of silica-supported nickel phosphide catalysts in the hydrodeoxygenation (HDO) of aliphatic model compound methyl palmitate (C15H31COOCH3) has been considered. Nickel acetate (Ni(OAc)2) and diammonium hydrogen phosphate ((NH4)2HPO4) (phosphate precursor) or nickel hydroxide (Ni(OH)2) and phosphorous acid (H3PO3) (phosphite precursor) have been used for the catalyst preparation by incipient wetness impregnation of SiO2 with an aqueous solution of the precursors, followed by temperature-programmed reduction in hydrogen flow. Chemical analysis (ICP-AES), H2-TPR, NH3-TPD, 31P MAS NMR, XRD, and TEM have been employed for the characterization of the catalysts. The optimal reduction parameters of the silica-supported nickel phosphide catalysts have been found for the phosphate and phosphite precursors in terms of their activity in methyl palmitate HDO. The Ni2P/SiO2 catalysts prepared by the phosphite method have shown higher catalytic activity in comparison with the Ni2P/SiO2 catalysts prepared by the phosphate method. The activity has been shown to depend on the catalyst handling after reduction: in situ reduced catalysts demonstrate higher conversion of methyl palmitate than the samples exposed to the reduction, passivation and re-reduction steps.

HKUST-1 silica aerogel composite (HKUST-1@SiO2) has been studied as a stationary phase for the efficient separation of unsaturated hydrocarbons from saturated aliphatics by conventional liquid chromotography (LC). HKUST-1@SiO2 has been prepared via an advanced sol–gel method and subsequent drying in supercritical CO2 to minimize the deterioration of the individual properties of the MOF and silica aerogel structures and tune its properties to be acceptable for flow mode. The synthesized composite was characterized by X-ray diffraction, FT-IR spectroscopy, XPS, scanning electron microscopy with EDAX mapping and low-temperature nitrogen adsorption. According to these data, the composite represents physically dispersed domains of HKUST-1 in the silica aerogel network. It was shown that the HKUST-1@SiO2 composite can be used as a highly efficient stationary phase for conventional liquid chromatographic separation of cyclohexene or benzene from cyclohexane. This is the first time a MOF composite has been used for the separation of organic molecules by LC, demonstrating new vistas for the application of these materials in the flow mode.

A series of unsaturated secondary amines was successfully synthesized by direct reductive amination of aliphatic aldehydes with nitroarenes over a 2.5% Au/Al2O3 catalyst in a continuous flow reactor using molecular hydrogen as a reducing agent. In most cases, the targeted secondary amines were obtained in good to excellent yields. Interestingly, the hydrogenation of CC group is practically absent in both initial aldehydes and secondary amines under the reaction conditions. It was found that the introduction of electron-donating substituents in the para- and meta-position of nitrobenzenes increased the yield of secondary amine, while in the case of nitrobenzenes with electron-withdrawing substituents or electron-donating substituents in the ortho-position a decrease in the yield of the target product was observed.

The effect of the reduction conditions on the physicochemical and catalytic properties of Ni2P/SiO2 catalysts was studied. The catalysts were prepared by impregnating silica with a solution of nickel acetate and diammonium hydrogen phosphate followed by drying, calcination, and temperature-programmed reduction. The Ni2P/SiO2 catalysts were reduced prior to hydrodeoxygenation (HDO) of methyl palmitate in the catalytic reactor (in situ) at temperatures of 550, 600, and 650 °С for 3 h and at 600 °С for 1 and 6 h. The reduction temperature and reduction time were shown to affect the conversion of methyl palmitate, and the optimal reduction conditions of the Ni2P/SiO2 catalysts were found. The Ni2P/SiO2 catalyst synthesized according to a widely used preparation method, including steps of passivation and rereduction at 450 °С in addition to the reduction step, is inferior in activity to the samples prepared in situ.

Thiophenic compounds are the least reactive organosulfur compounds in fossil fuels, and thiophene is widely used as a model substrate in studies of industrially important hydrodesulfurization (HDS) processes. It is generally presumed that the HDS process can proceed by two possible pathways, namely hydrogenation or direct desulfurization. In this work, the parahydrogen-induced polarization technique was successfully utilized in a mechanistic study of a hydrodesulfurization reaction by example of a heterogeneous hydrodesulfurization of thiophene over supported catalysts in the presence of parahydrogen. It was demonstrated that the HDS of thiophene on a MoS2/γ-Al2O3 catalyst proceeds preferentially by the hydrogenation pathway to form tetrahydrothiophene, followed by desulfurization. In contrast, if a Pt/TiO2 catalyst was used, direct desulfurization to 1,3-butadiene and the hydrogenation pathway both contributed to the overall reaction mechanism.

One-pot reductive amination of aromatic and aliphatic aldehydes with nitroarenes over an Au/Al2O3 catalyst in a continuous flow reactor using molecular hydrogen as a reducing agent was performed. Various secondary aromatic amines were obtained in good to excellent yields.

Problems related to granular catalysts testing in hydrotreatment of petroleum distillates in laboratory are discussed. Requirements for laboratory facilities that ensure high reliability in determining the performance of diesel fraction hydrotreatment in industrial reactors are formulated. It is shown that diluting catalyst pellets with small particles of inert nonporous material (silicon carbide) allows us to obtain reproducible results in small three-phase reactors, minimizing such factors as the incomplete wetting of the catalyst, the wall effect, and the back-mixing of liquids. Laboratory facilities and analysis techniques are described, and results obtained at different laboratories in studying catalysts for the deep hydrotreatment of diesel fractions are compared.

The Ni2P/SiO2 catalyst, which was prepared by in situ temperature-programmed reduction and in the mixture with the inert (SiC, SiO2) or acidic (γ-Al2O3) material was studied in methyl palmitate hydrodeoxygenation (HDO). Methyl palmitate HDO was carried out at temperatures of 270–330 °C, H2/feed volume ratio of 600 Nm3/m3, and H2 pressure of 3.0 MPa. Ni2P/SiO2 catalyst, diluted with γ-Al2O3 showed a higher activity than Ni2P/SiO2 catalyst diluted with SiC or SiO2. The conversion of methyl palmitate increased significantly in the presence of γ-Al2O3 most probably due to the acceleration of the acid-catalyzed reaction of ester hydrolysis. The synergism of Ni2P/SiO2 and γ-Al2O3 in methyl palmitate HDO can be explained by the cooperation of the metal sites of Ni2P/SiO2 and the acid sites of γ-Al2O3 in consecutive metal-catalyzed and acid-catalyzed reactions of HDO. The obtained results let us conclude that the balancing of metal and acid sites plays an important role in the development of the efficient catalyst for the HDO of fatty acid esters over supported phosphide catalysts.

Two sets of silica-supported nickel phosphide catalysts with a nickel content of about 2.5 and 10 wt % and Ni/P molar ratio 2/1, 1/1 and 1/2 in each set, were prepared by way of a temperature-programmed reduction method using (Ni(CH3COO)2) and ((NH4)2HPO4) as a precursor. The NixPy/SiO2 catalysts were characterized using chemical analysis N2 physisorption, XRD, TEM, 31P MAS NMR. Methyl palmitate hydrodeoxygenation (HDO) was performed in a trickle-bed reactor at 3 MPa and 290 °C with LHSV ranging from 0.3 to 16 h−1. The Ni/P ratio was found to affect the nickel phosphide phase composition, POx groups content and catalytic properties in methyl palmitate HDO with the TOF increased along with a decline of Ni/P ratio and a growth of POx groups’ content. Taking into account the possible routes of methyl palmitate conversion (metal-catalyzed hydrogenolysis or acid-catalyzed hydrolysis), we proposed that the enhancement of acid POx groups’ content with the Ni/P ratio decrease provides an enhancement of the rate of methyl palmitate conversion through the acceleration of acid-catalyzed hydrolysis.

CoMo/Al2O3 sulfide catalysts varying in preparation method and Co/Mo ratio have been tested in the hydrorefining of a mixture of straight-run diesel fraction and rapeseed oil in a flow reactor at a temperature of 340–360°C, a hydrogen pressure of 4.0–7.0 MPa, and a liquid hourly space velocity of 1–2 h−1. A comparison between catalysts prepared using citric acid (CoMo/Al2O3-1.5) and both citric and orthophosphoric acids (CoMoP/Al2O3-1.5) as promoters, with Co/Mo = 0.3 and 0.5, has demonstrated that the most active catalyst in hydrodesulfurization and hydrodenitrogenation is the phosphorus-containing Co/Mo ≈ 0.5 sample. The addition of rapeseed oil to straight-run diesel fraction lowers the hydrodesulfurization and hydrodenitrogenation activities of the CoMo sulfide catalysts, irrespective of the method by which they were prepared. The fatty acid triglyceride conversion selectivity of these catalysts depends on the Co/Mo ratio and on reaction conditions: decreasing the Co/Mo ratio from 0.46 to 0.26, lowering the reaction temperature, and raising the hydrogen pressure and hydrogen-to-feedstock ratio increase the C18/C17 hydrocarbon ratio in the hydrogenated product. The addition of rapeseed oil improves the quality of the product; however, for attaining the preset residual sulfur level in this case, the process needs to be conducted at a higher temperature than the hydrorefining of straight-run diesel fraction containing no admixture.

Detected by the in situ EPR spectroscopy immobilized nitro radical anions generated in the course of Au/Al2O3-catalyzed nitrobenzene hydrogenation demonstrate the abnormal hyper-fine splitting and serve as intermediates of the reaction.

The challenges of the modern society and the growing demand of high-technology sectors of industrial production bring about a new phase in the development of organic synthesis. A cutting edge of modern synthetic methods is introduction of functional groups and more complex structural units into organic molecules with unprecedented control over the course of chemical transformation. Analysis of the state-of-the-art achievements in selective organic synthesis indicates the appearance of a new trend — the synthesis of organic molecules, biologically active compounds, pharmaceutical substances and smart materials with absolute selectivity. Most advanced approaches to organic synthesis anticipated in the near future can be defined as 'atomic precision' in chemical reactions. The present review considers selective methods of organic synthesis suitable for transformation of complex functionalized molecules under mild conditions. Selected key trends in the modern organic synthesis are considered including the preparation of organofluorine compounds, catalytic cross-coupling and oxidative cross-coupling reactions, atom-economic addition reactions, methathesis processes, oxidation and reduction reactions, synthesis of heterocyclic compounds, design of new homogeneous and heterogeneous catalytic systems, application of photocatalysis, scaling up synthetic procedures to industrial level and development of new approaches to investigation of mechanisms of catalytic reactions. The bibliography includes 840 references.

The catalytic properties of sulfided Mo/Al2O3, CoMo/Al2O3 and NiMo/Al2O3 catalysts in the hydrodeoxygenation of methyl palmitate as a model compound for triglyceride feedstock were studied at 300 °C and 3.5 MPa in the batch reactor using n-tetradecane, m-xylene and hydrotreated straight-run gas oil (HT-SRGO). The comparison of catalyst's performance in n-tetradecane allowed us to see that the sulfided Mo/Al2O3, CoMo/Al2O3 and NiMo/Al2O3 catalysts revealed the same rate of the methyl palmitate conversion but the rate of the intermediate oxygenates conversion decreased in order: CoMoS/Al2O3 > NiMoS/Al2O3 > MoS2/Al2O3. A mixture of linear saturated and unsaturated C15 and C16 hydrocarbons was produced when the oxygenates were fully consumed. The main products obtained over the Mo/Al2O3 and CoMo/Al2O3 catalysts were C16 hydrocarbons (C16/C15 – 16.1 and 2.79, respectively); however, C15 hydrocarbons were preferentially formed over the NiMo/Al2O3 catalyst (C16/C15 – 0.65), highlighting the different contributions of the hydrodeoxygenation (HDO) and decarboxylation/decarbonylation (DeCOx) pathways during the hydroconversion of methyl palmitate over these catalysts. Investigating the solvent's influence on the activity of the CoMo/Al2O3 and NiMo/Al2O3 catalysts in the methyl palmitate HDO revealed that the reaction rate was decreased in the following order: n-tetradecane > HT-SRGO > m-xylene. The aromatic compounds did not retard the methyl palmitate transformation, but inhibited the conversion of the intermediate oxygenates. Decreased C16/C15 ratios were observed over both catalysts when m-xylene was used as the reaction medium instead of n-tetradecane.

The ferromagnetic resonance (FMR) method in situ is used to study the initial stages of the formation of ɛ iron oxide nanoparticles deposited on silica gel at temperatures up to 600°C. It is shown that at high-temperature treatment of starting samples obtained by impregnation with an iron(II) sulfate solution, supermagnetic ɛ-Fe2O3/SiO2 nanoparticles form with a narrow size distribution. An analysis of the FMR data in comparison with the data of other methods enables the formulation of the formation conditions for systems of deposited ɛ-Fe2O3 nanoparticles without other polymorph impurities.

Nitrobenzenes are reduced to the corresponding anilines with nearly full conversion and excellent selectivities while reduction-sensitive substituents (e.

Methylation reaction of indole was studied in supercritical methanol (350 °C, 215 atm) catalyzed by TMOS and TEOS. Use of both orthosilicates shows the same result of indole methylation. The indole conversion is ∼30% for 5 h of the reaction with and without catalysts. But catalytic reaction is more high-selective on 3-methyl-1H-indole formation – 95–96 mol% against 60 mol% for non-catalytic methylation. Indole conversion in catalytic reaction increases by a quarter (with no change of selectivity) when two equivalents of water are added into reaction mixture. Methylating system was assumed to be the TMOS–MeOH, and methylation proceeds via cyclic, multi-centered transition state (TS). The TS involves molecules of indole, TMOS, methanol, and water (if used), which are orientated in a certain way to each other by hydrogen and coordinate bonding. The reaction does not occur in supercritical ethanol or isopropanol with and without using the catalysts.

The effect of calcination temperature on the state of the active component of iron-containing catalysts prepared by the impregnation of silica gel with a solution of FeSO4 and on their catalytic properties in selective H2S oxidation to sulfur was studied. With the use of thermal analysis, XPS, and Mossbauer spectroscopy, it was found that an X-ray amorphous iron-containing compound of complex composition was formed on the catalyst surface after thermal treatment in the temperature range of 400–500°C. This compound contained Fe3+ cations in three nonequivalent positions characteristic of various oxy and hydroxy sulfates and oxide and sulfate groups as anions. Calcination at 600°C led to the almost complete removal of sulfate groups; as a result, the formation of an oxide structure came into play, and it was completed by the production of finely dispersed iron oxide in the ɛ-Fe2O3 modification (the average particle size of 3.2 nm) after treatment at 900°C. As the calcination temperature was increased from 500 to 700°C, an increase in the catalyst activity in hydrogen sulfide selective oxidation was observed because of a change in the state of the active component. A comparative study of the samples by temperature-programmed sulfidation made it possible to establish that an increase in the calcination temperature leads to an increase in the stability of the iron-containing catalysts to the action of a reaction atmosphere.

An approach is suggested to synthesize the e-Fe2O3 particles supported on silica with the mean size of few nanometers, narrow size distribution and no admixture of any other iron oxide polymorphs. The facile synthesis is based on the pore filling impregnation method by iron sulfate (II) water solution with the following annealing procedure at ~1173 K. It is shown that the e-Fe2O3 nanoparticles obtained are stable up to ~1173 K and possess superparamagnetic behavior up to ~870 K.