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Levulinic acid (LA) is one of the substances, which can be obtained from cellulosic biomass via acid hydrolysis and serves as a precursor in the synthesis of gamma-valerolactone (GVL) – platform chemical for so-called valeric fuels. This work is devoted to the study of catalytic conversion of LA to GVL using mono- (Ru) and bimetallic (Ru-Co) catalysts based on ruthenium-containing nanoparticles immobilized in hyper-crosslinked polystyrene (HPS). It was shown that RuO2 nanoparticles are an active phase of HPS-based Ru catalysts, which allow nearly 100 % yield of GVL at 120 °C and 2 MPa of hydrogen partial pressure for the reaction time 60 min. Introduction of cobalt in catalyst composition in a proper amount (Ru-to-Co weight ratio is 30) was found to result in Ru redistribution inside the polymeric support and, in turn, to the increase of reaction rate of LA hydrogenation.

Here, for the first time, we developed a catalytic composite by forming a thin layer of a cross-linked hyperbranched pyridylphenylene polymer (PPP) on the surface of mesoporous magnetic silica (Fe3...

Hydrotreatment of bio-oil oxygen compounds allows the final product to be effectively used as a liquid transportation fuel from biomass. Deoxygenation is considered to be one of the most promising ways for bio-oil upgrading. In the current work, we describe a novel approach for the deoxygenation of bio-oil model compounds (anisole, guaiacol) using supercritical fluids as both the solvent and hydrogen-donors. We estimated the possibility of the use of complex solvent consisting of non-polar n-hexane with low critical points (Tc = 234.5 ºC, Pc = 3.02 MPa) and propanol-2 used as H-donor. The experiments were performed without catalysts and in the presence of noble and transition metals hydrothermally deposited on the polymeric matrix of hypercrosslinked polystyrene (HPS). The experiments showed that the presence of 20 vol. % of propanol-2 in n-hexane results in the highest (up to 99%) conversion of model compounds. When the process was carried out without a catalyst, phenols were found to be a major product yielding up to 95 %. The use of Pd- and Co-containing catalyst yielded 90 % of aromatic compounds (benzene and toluene) while in the presence of Ru and Ni cyclohexane and methylcyclohexane (up to 98 %) were the main products.

In this paper synthesized palladium (Pd)-containing catalysts were used in the hydrogenolysis of lignin in the presence of a hydrogen donor solvent, i-propanol, to obtain liquid fuel components. A study of the influence of the catalyst support nature, catalyst preparation method and supercritical solvent nature on the lignin depolymerization was completed. It was found that the use of Pd-containing catalysts results in the formation of aromatic compounds (mainly benzene and toluene) for both supercritical solvents used (i-propanol and CO2). The maximum conversion of lignin (50 %) was achieved when the supercritical i-propanol was used and maximum selectivity to aromatics (over 70 %) was observed in the presence of the Pd-containing catalyst synthesized by hydrothermal deposition on the polymeric matrix of hyper-crosslinked polystyrene.

This work is devoted to kinetic modelling of levulinic acid (LA) hydrogenation to gamma-valerolactone (GVL) in aqueous medium in a batch mode using 5%-Ru/MN100 catalyst, which comprises Ru dioxide nanoparticles confined in polymeric network of hyper-crosslinked polystyrene of MN100 type. Kinetic models of liquid-phase hydrogenation of LA to GVL were proposed based on Langmuir–Hinshelwood and Eley–Rideal mechanisms. Calculations based on experimental data obtained during the study allowed determining the main kinetic parameters of LA hydrogenation reaction and to propose the rate expression adequately describing the catalytic process. Moreover, hypothesis on the reaction mechanism was proposed considering RuO2 as catalytically active phase and 4-hydroxypentanoic acid as main intermediate compound.

In the current paper, the possibility of the use of magnetically separable catalysts containing ruthenium oxide species in the supercritical deoxygenation of stearic acid for producing of the second generation of biodiesel is reported. Three different supports (silica, ceria, and hypercrosslinked polystyrene) were used for the stabilization of magnetic nanoparticles (MNPs) and Ru-containing particles. The effect of support on the magnetic properties as well as the catalytic activity of the obtained systems was studied. All synthesized catalysts were shown to provide high stearic acid conversion (up to 95 %). The highest yield of C17+ hydrocarbons (up to 86 %) was observed while using the Ru–Fe3O4-HPS system. Ru–Fe3O4-HPS was characterized by the high values of the specific surface area (364 m2/g) and saturation magnetization (4.5 emu/g). The chosen catalytic system was found to maintain its catalytic activity for a minimum of 10 consecutive cycles.

Biocatalysts based on immobilized enzymes received considerable attention due to important applications in syntheses of value-added chemicals, pharmaceuticals and drug intermediates with great catalytic efficiency and high yields of target molecules. The important advantages of such biocatalysts are enhanced stability in tolerant pH and temperature range, separation from reaction solutions, stability in repeated use, and so on. In this review, we discuss recent findings in biocatalyst design, in particular, types of promising supports, the biocatalyst surface modification, and incorporation of magnetic nanoparticles for facilitated magnetic recovery. Furthermore, we highlight the development of multienzyme and enzyme/nanoparticle catalysts for cascade reactions, which are carried out in a one-pot process and allow elimination of isolation and purification of intermediates.

Rigid pyridylphenylene dendrons were shown to successfully function as capping molecules for stabilization of both magnetite and Pd nanoparticles (NPs) to form hydrophobic, magnetically recoverable catalysts. However, syntheses in colloidal solutions require large amounts of dendrons and are difficult to scale up. Here, we developed a strategy for the nanocomposite formation by immobilization of the pyridylphenylene dendrons (D) on magnetic silica (Fe3O4-SiO2, MS) surface via the formation of ether or amide bonds, depending on the structure of flexible linkers on the MS surface and dendron focal groups. Both approaches allow attachment of small amounts of the dendrons with high surface coverage and impart amphiphilicity to the final composite. After the binding to the MS surface, the dendron pyridine moieties readily complex with Pd acetate, leading to a “cocktail” of Pd2+ and Pd0 species (the latter forming Pd NPs) due to partial reduction by composite functional groups. The MS-D-Pd nanocomposites were tested in the model Suzuki-Miyaura cross-coupling reaction of 4-Br-anisole and phenylboronic acid to evaluate their performance in hydrophilic conditions. MS-D-Pd demonstrated excellent performance, even at a very small amount of the catalyst, which is assigned to exceptional stabilization by dendritic ligands, allowing prevention of the metal leaching and preservation of catalytic properties upon magnetic separation. The immobilization of rigid hydrophobic dendrons on the hydrophilic magnetic support may allow one to extend the scope of catalytic reactions due to catalyst amphiphilicity.

A physicochemical study of cobalt-containing (10 wt %) silica-supported Fischer–Tropsch catalysts was carried out. The catalysts were obtained under subcritical conditions (T = 200°C, P = 8 MPa) using water (Tc = 374.1°C, Pc = 22.1 MPa) and propanol-2 (Tc = 235.6°C, Pc = 5.8 MPa). The obtained samples were compared with a 10 wt % Co/SiO2 catalyst prepared by incipient-wetness impregnation. Comparison of the properties of catalysts in the liquid-phase Fischer–Tropsch synthesis showed that the sample prepared in subcritical water was the most active and selective to aliphatic C6–C7 hydrocarbons. This sample is characterized by a high surface area (131.7 m2/g), a uniform distribution of particles in the active phase with an average size of 5 nm and higher accessibility of cobalt species for reagents. According to XPS data, the composition of catalyst active phase is mainly represented by two compounds: Co(OH)2 and Co3O4.

Статья посвящена разработке палладиевых катализаторов на носителях, исследованию их структуры, каталитических свойств и их корреляции с активностью катализаторов в гидрировании п-нитроанилина. Серия палладиевых нанесенных катализаторов была синтезирована с использованием носителей: Al2O3, SiO2 и угля АР-Д для стабилизации частиц Pd с загрузкой активного металла 3, 4, 5 мас. долей (%). Образцы катализаторов были синтезированы с использованием метода осаждения и охарактеризованы сканирующей электронной микроскопией, температурно-программируемым восстановлением, физической сорбцией азота, инфракрасной спектроскопией и испытаны в процессе каталитического гидрирования п-нитроанилина. В работе показан эффективный подход получения функциональных материалов с точки зрения применения катализа. Основными преимуществами такого подхода являются дешевизна и простота внедрения, которые дают возможность получать функциональные материалы прямо на месте применения. Все используемые химикаты широко доступны, и дополнительное оборудование не требуется. Активность образцов катализаторов в процессе гидрирования п-нитроанилина имеет сильную корреляцию со значениями дисперсности нанесенного металла и кислотностью носителя. Образец с 5 мас.% Pd/γ-Al2O3 показывает наибольшую активность ~ 4,6 ∙ 10-5 моль (H2)/с., где носитель катализатора характеризуется высокой кислотностью, а нанесенный металл умеренной дисперсностью. Сравнение данных активности катализатора и содержания пор различных размеров показало определенную корреляцию. После реакции гидрирования 4-нитроанилина изменение размеров пор катализаторов может дать косвенную информацию о предполагаемых физических процессах, происходящих на поверхности катализатора. В целом, по полученным результатам была обнаружена корреляция между структурой, физико-химией катализатора и его активностью в гидрировании п-нитроанилина.

This work aimed to study the influence of catalyst supports on their catalytic activity and physico-chemical properties of resulting material. Such supports as SiO2, γ-Al2O3 and carbon containing 3, 4 or 5% palladium are used for the experiments. The hydrogenation of p-nitroaniline is chosen as a model reaction for testing the synthesized catalysts. Catalysts were studied by different physico-chemical methods in order to reveal the structure and its changes in reaction. XPS data shows the catalyst surface changed its chemical structure. The palladium oxidation state strongly depends on the nature of the matrix. For γ-Al2O3- and SiO2-supported catalysts, the formation of palladium(II) oxide was found to take place, at the same time, the carbon support is characterized by the presence of both palladium(II) oxide and palladium(IV) oxide. Such a difference shows that the nature of the support influences the oxidation state of active metal. The application of carbon matrix provides a lower oxidation state of the active metal due to electron density shift to the support. Temperature programmed desorption of NH3 demonstrates γ-Al2O3 to contain weak, medium and strong acid sites, while activated carbon has only medium and weak ones. Silica has only weak acid sites. A correlation between catalyst activity and acid–base properties was shown.

Here, the development of a new catalyst is reported for the selective furfural (FF) hydrogenation to furfuryl alcohol (FA) based on about 7 nm sized Pd-Cu alloy nanoparticles (NPs) formed in inexpensive, commercially available micro/mesoporous hypercrosslinked polystyrene (HPS). A comparison of the catalytic properties of as-synthesized and reduced (denoted "r") catalysts as well as Pd-Cu alloy and monometallic palladium NPs showed a considerable enhancement of the catalytic performance of Pd-Cu/HPS-r compared to other catalysts studied, resulting in about 100 % FF conversion, 95.2 % selectivity for FA and a TOF of 1209 h-1 . This was attributed to the enrichment of the NP surface with copper atoms, disrupting the furan ring adsorption, and to the presence of both zerovalent and cationic palladium and copper species, resulting in optimal hydrogen and FF adsorption. These factors along with exceptional stability of the catalyst in ten consecutive catalytic cycles make it highly promising in practical applications.

The synthesis of catalytically active bimetallic Au–Pd nanoparticles stabilized in hyper-cross-linked polystyrene (HPS) for Suzuki cross-coupling of 4-bromoanisole (4-BrAn) and phenylboronic acid is presented. The core–shell structure with a thin (less than 1 nm) Pd shell and a Au core was proven by X-ray diffraction and high-angle annular dark-field scanning transmission electron microscopy combined with energy-dispersive X-ray spectroscopy. More than a 2-fold increase in 4-BrAn conversion was found in comparison with monometallic Pd/HPS. Moreover, when the Suzuki reaction was carried out under visible-light irradiation, the product yield further increased by about 1.3 times (from 56.1% up to 73.7%). This effect was assigned to a local surface plasmon resonance arising in the Au core that allowed electron transfer to the extremely thin Pd layer due to intimate contact with gold. The results suggest that the rate-limiting step of the catalytic cycle takes place on the surface of the Pd shell, serving as e...

Here, we developed magnetically recoverable biocatalysts for enzymatic oxidation of d-glucose to d-gluconic acid with high product yields. The catalyst support is based on nanoparticle clusters (NPCs) composed of magnetite particles and coated with the amino terminated silica layer to facilitate further functionalization. It involves the attachment of the glutaraldehyde linker followed by the covalent attachment of glucose oxidase (GOx) via its amino groups. It was established that the NPCs with a diameter of ∼430 nm attach 33% more GOx molecules than NPCs with a diameter of ∼285 nm, although the surface area of the former is lower than that of the latter. At the same time, the biocatalyst based on the smaller NPCs shows higher relative activity of 94% than that (87%) of the biocatalyst based on the larger NPCs, both at 50 °C and pH 7 (optimal reaction conditions). This surprising result has been explained by a combination of two major factors such as GOx crowding on the support surface which should preve...

Inulin is a naturally occurring polysaccharide, widely available as plant biomass. Here, we report utilization of a magnetically separable Ru-containing catalyst based on magnetic silica (Fe3O4-SiO2) in the inulin hydrolytic hydrogenation to mannitol (a sweetener used in diabetic foods). The influence of the reaction parameters on the selectivity to mannitol has been studied. Under the optimal conditions the maximum selectivity to mannitol reached 44.3% at 100% conversion of the initial polysaccharide, exceeding that obtained with conventional Ru/C. The catalyst used in this work is stable under hydrothermal conditions of the process. It can be easily magnetically separated from the reaction mixture and reused without any loss of selectivity and activity, making this catalyst promising for practical applications in biomass conversion.

In the current work, the use of Ni-containing catalyst on the base of hypercrosslinked polystyrene in the stearic acid (SA) hydrodeoxygenation (HDO) in the medium of supercritical n-hexane is presented. The catalyst was synthesized by the hydrothermal deposition of Ni-containing particles into the pores of the polymeric matrix in the medium of superheated water. It was found that the catalyst is characterized by the high surface area and the uniform deposition of the active phase on the catalyst surface. Ni in the catalyst is represented by NiOOH. The mean particle diameter of the active phase was found to be 5.5 nm. The catalyst showed high efficiency in the SA HDO in the medium of supercritical n-hexane reaching the C16–C17 yield up to 90 at 100% substrate conversion. It was shown that the catalyst maintained its activity in minimum five consecutive runs without sufficient loose selectivity.

In the current work, we present the study of the catalytic performance and characterization of the modified H-ZSM-5 zeolite for methanol to hydrocarbons process. The modification of zeolite was performed by both alkali and acid treatment. The changes in the zeolite structure were studied using low-temperature nitrogen physisorption, NH3 chemisorption, and X-Ray photoelectron spectroscopy. It was found that the zeolite modification with oxalic acid (0.01 M) resulted in the lower catalytic activity loss (48%) after 120 h on stream as compared to both initial and alkali treated H-ZSM-5. Further, the chosen zeolite sample was modified with Co, Fe, and Ni by wet impregnation with the corresponding metal nitrates. The Ni-containing catalyst showed the highest catalytic performance in time on stream. The decrease in the methanol transformation rate for the Ni-containing zeolite was found to be only 27%. The metal-containing catalysts showed the minimal coke formation as well as the minimal decrease in acidity and surface area as compared to the initial zeolite and the samples treated with both alkali and oxalic acid.

Here, we report on the development of novel Zn-, Zn-Cr-, and Zn-Cu-containing catalysts using magnetic silica (Fe3O4-SiO2) as the support. Transmission electron microscopy, powder X-ray diffraction, and X-ray photoelectron spectroscopy (XPS) showed that the iron oxide nanoparticles are located in mesoporous silica pores and the magnetite (spinel) structure remains virtually unchanged despite the incorporation of Zn and Cr. According to XPS data, the Zn and Cr species are intermixed within the magnetite structure. In the case of the Zn-Cu-containing catalysts, a separate Cu2O phase was also observed along with the spinel structure. The catalytic activity of these catalysts was tested in methanol synthesis from syngas (CO + H2). The catalytic experiments showed an improved catalytic performance of Zn- and Zn-Cr-containing magnetic silicas compared to that of the ZnO-SiO2 catalyst. The best catalytic activity was obtained for the Zn-Cr-containing magnetic catalyst prepared with 1 wt % Zn and Cr each. X-ray absorption spectroscopy demonstrated the presence of oxygen vacancies near Fe and Zn in Zn-containing, and even more in Zn-Cr-containing, magnetic silica (including oxygen vacancies near Cr ions), revealing a correlation between the catalytic properties and oxygen vacancies. The easy magnetic recovery, robust synthetic procedure, and high catalytic activity make these catalysts promising for practical applications.

We report hydrogenation of furfural (FF) to furfuryl alcohol (FA) with novel Pt-and Pd-containing magnetite nanoparticles (NPs) stabilized by polyphenylquinoxaline (PPQ) and hyperbranched pyridylphenylene polymer (PPP). FF is one of the major ingredients of biooil produced by biomass pyrolysis, while FA is a source of value-added chemicals, thus, creating a sustainable path from biomass to important compounds. We demonstrate that catalytic NPs (Pt0 or Pd0) of approximately 3 nm in diameter form in the polymer shells of magnetite NPs and the catalysts are magnetically recoverable. The search for optimal reaction conditions of the FF hydrogenation revealed that the highest selectivity is obtained at 120 °C and 6 MPa hydrogen pressure in i-propanol as solvent. The solvent effect is due to combination of good FF solubility and accessibility of catalytic NPs for the FF adsorption. A comparison of the catalytic activities of the Pd-containing magnetite NPs stabilized by PPQ and PPP validates the advantages of the open and rigid structure of the hyperbranched PPP vs. linear PPQ. For Pd-containing magnetite NPs stabilized by PPP, the high selectivity to FA of 99.3% at nearly 100% FF conversion was achieved at a remarkable activity of 871 min−1 and high catalyst stability.

Transition metal nanoparticles (NPs) are extensively used as catalysts for a wide and diverse range of organic transformations when immobilized on appropriate solid supports. We describe the development of a highly active and highly selective heterogeneous catalyst based on Ni-Au NPs supported on activated carbon fibers (ACFs) for the partial reduction of m -dinitrobenzene ( m -DNB) to m -nitroaniline ( m -NAN), an important platform chemical used in the synthesis of dyes and polymers. Initially, Ni NPs with narrow size distribution and ranging from 2 to 14 nm were prepared with poly-N-vinyl-2-pyrrolidone (PVP) as a stabilizer. Evaluation of the NPs as catalysts in the liquid-phase hydrogenation of m -dinitrobenzene led to the establishment of an antipathetic structure sensitivity, i.e. the larger NPs displayed a 6-fold higher turnover frequency than the smaller NPs. The selectivity to the target m -NAN product is independent of the size of the Ni NPs, possibly due to preferential PVP absorption of the NP edges and vertices. Consequently, Ni NPs of 2 nm were supported on ACFs and residual PVP was removed by a ultra-violet ozone (UVO) treatment, rendering a highly selective structured catalyst that affords m -NAN in almost 96% yield. A two-site (plane vs. edge Ni-atoms) Langmuir–Hinshelwood kinetic model is consistent with the experimental kinetic data confirming that low-coordination atoms (edges and vertices) are responsible for selective reaction. Consequently, we prepared bimetallic Ni-Au NPs (Ni:Au = 1:1) aiming to generate Ni surface sites mimicking the properties of edge and vertex atoms. The resulting UVO-treated Ni-Au NPs of 3 nm immobilized on ACFs afford m -NAN with a yield exceeding 98%. Such a high yield appears to be unprecedented and shows how careful nanocatalyst design, guided by detailed structural characterization and mechanistic studied, can lead to highly selective catalysts of industrial relevance.

It is shown that the reactive adsorption of sulfur contaminated compounds over transition metal (TrM) polycation exchanged zeolites is a very efficient way for desulfurization of hydrocarbon processing streams. The process consists of physical adsorption of thiols, sulfides, and disulfides and catalytic oxidation of the adsorbed substances. The reaction does not require free oxygen participation and DRIFTS and XAS studies confirmed that thiols oxidation proceeds through direct involvement of TrM polycation superoxides. All studied materials Zn, Mn, Cu, Cd polycation containing zeolites X, Y, and mordenite show remarkable activity in sulfur compounds oxidation, resulting in a significant increase of their total pick-up from gas and liquid hydrocarbons. The thermal regeneration of the catalyst-adsorbents at oxidizing conditions leads to the complete restoration of their original activity and capacity for sulfur compounds removal. The suitable operating conditions for the regeneration process are disclosed. The research also demonstrates favorable opportunities for the suggested catalyst-adsorbents in such commercially important applications as natural gas and liquid hydrocarbons desulfurization.

This paper is devoted to the study of oil-containing residue (oil-slime) pyrolysis process in the presence of cobalt chloride as a catalyst. A mixture consisting of crude oil (20 wt.%) and silica (80 wt.%) was used as a model substrate. The pyrolysis process carried out at a temperature 500 °C in nitrogen atmosphere in the presence of 5 wt.% of CoCl2 allowed obtaining an optimal gaseous, liquid and solid product distribution. Moreover the comparison of liquid and solid pyrolysis products composition with those obtained in non-catalytic process was done. It was found that the use of CoCl2 increases the calorific value of both gaseous and liquid products due to the increase in hydrocarbon formation. Pyrolysis solid residue was found to consist of silica particles coated with pyrolysis graphite and can be used as a valuable sorbent.

The chemoselective three-phase hydrogenation of an Ombrabulin intermediate based on a nitro-stilbene framework was used as a case study for the formation of the primary amine without affecting the C C double bond. Two catalysts were tested: Pt nanoparticles supported on ZnO (Pt/ZnO) and agglomerated nitrogen-doped carbon nanotubes (NCNTs). Both materials show a high selectivity at close to full conversion in terms of amine formation (>99%) without changing the configuration of the central stilbene C C double bond. The continuous hydrogenation process was first tested in lab scale reactors (2 mL and 6 mL) combined with a high pressure interdigital micromixer to ensure efficient three-phase contact. While the specific reactor performance (defined as productivity per unit of reactor volume) was 1.5-fold higher for the Pt/ZnO, the NCNT catalyst was found to be more suitable for flow operation due to a lower pressure drop over the catalytic packed bed. The catalytic reactor was then scaled up to 50 mL and operated in the EcoTrainer mobile modular platform for the hydrogenation of the Ombrabulin intermediate demonstrating a safe, flexible and sustainable fine chemical synthesis.

This work is devoted to the investigation of the possibility of the use of Ru-containing catalysts on the basis of polymeric matrix of hypercrosslinked polystyrene (HPS) in the hydrogenation of levulinic acid (LA) to gamma-valerolactone (GVL). HPS-based Ru-containing catalysts were synthesized at variation of HPS type (MN100 bearing amino groups or MN270 without functional groups) and metal content. Catalyst 5%-Ru/MN100 was shown to compete with commercial 5%-Ru/C and to allow carrying out the hydrogenation of LA in aqueous medium with high yields of GVL (more than 99%).

Stearic acid hydrodeoxygenation into n-heptadecane on the catalyst containing Pd nanoparticles incorporated in the hypercrosslinked polystyrene matrix was studied. The used catalysts were characterized using TEM, CO chemisorption, low-temperature nitrogen physisorption and XPS. A clear hydrogen pressure dependent induction period was noticed. Kinetic regularities were studied for the indicated reaction in the presence of polymer based catalysts. A mathematical model for decarboxylation was suggested which was able to adequately describe experimental data at different temperatures, hydrogen pressures and initial concentrations of stearic acid. Kinetic constants were calculated and their statistical analysis was performed.

The study presents the results of cellulose hydrolytic hydrogenation process in subcritical water in the presence of Ru-containing catalysts based on hypercrosslinked polystyrene (HPS) MN-270 and its functionalized analogues: NH2-HPS (MN-100) and SO3H-HPS (MN-500). It was shown that the replacement of the traditional support (carbon) by HPS increases the yield of the main cellulose conversion products – polyols – important intermediates for the chemical industry. The catalysts were characterized using transmission electron microscopy (TEM), high resolution TEM, and porosity measurements. Catalytic studies demonstrated that the catalyst containing 1.0% Ru and based on MN-270 is the most active. The total yield of sorbitol and mannitol was 50% on the average at 85% cellulose conversion.

We report herein on the development of Ni-based catalyst using activated carbon fibres (ACFs) as a structured support and its application for the three‐phase hydrogenation of nitroarenes (T = 353 K; P = 10 bar). It was shown that metallic Ni0 nanoparticles (NPs) with a mean diameter of ∼2.0 nm stabilized by the ACF microporous network were responsible for the catalytic transformation. To obtain optimum catalytic activity, the Ni/ACF catalyst must be freshly prepared and activated in situ by H2 at T > 353 K. Pre-treatment of the ACFs by nitric acid boosted the activity of the Ni/ACF catalyst, which exhibits high performance in hydrogenation of nitrobenzene to aniline (yield, Y ∼100%). The catalyst was tested for the reuse attaining a quasi-steady-state after the sixth reaction thereafter remaining relatively stable over seven consecutive runs. Near-quantitative transformation (Y > 99%) of p-chloronitrobenzene to p‐chloroaniline was achieved under mild conditions over the Ni/ACF catalyst with a ca. 20-fold higher activity than conventional Raney Ni. Thus, new catalyst reported here represents a significant step forward towards a simple, heterogeneous catalytic selective hydrogenation of nitroarenes that employs H2 as the hydrogen source.

This paper describes synthesis of Pd-containing catalysts of Suzuki cross-coupling based on amino-functionalized hyper-cross-linked polystyrene at variation of Pd precursor nature (PdCl2, PdCl2(CH3CN)2, or PdCl2(PhCN)2). The investigation of the influence of palladium oxidation state (Pd(II) or Pd(0)) and form (Pdn clusters or Pd nanoparticles) on the rate of Suzuki cross-coupling of 4-bromoanisole and phenylboronic acid is discussed. Developed catalysts are shown to allow achieving conversion of 4-bromoanisole higher than 98% under mild reaction conditions. Independently of the precursor nature, Pd(II) is mainly responsible for observed catalytic activity. However, preliminary reduction of catalysts with H2 results in formation of a large number of Pdn clusters, the contribution of which in the Suzuki reaction becomes predominant.

Encapsulation of metal nanoclusters in porous solid polymer materials is a promising approach to combine the outstanding properties of both, heterogeneous and homogeneous catalysts. We report heterogeneous nano-engineered catalysts containing Pd-nanoparticles (NPs) confined within highly-porous hollow polymeric framework of hyper cross-linked polystyrene (HPS). HPS with different surface functionalities (amine vs. sulfonate) were used for impregnation by Pd precursors of different nature and followed by a variety of catalyst post-treatments. The catalysts have been tested in two model key reactions for the synthesis of fine chemicals: selective hydrogenation of 2-methyl-3-butyne-2-ol to 2-methyl-3-butene-2-ol (MBE) and Suzuki cross-coupling of 4-bromoanisole with phenylboronic acid. Optimization of the Pd/HPS preparation and reaction conditions allowed attaining high selectivity (~99 %) to target MBE at close to full conversion. For Suzuki cross-coupling more than 90 % yield of coupling product was obtained under mild reaction conditions and the absence of phase transfer agent. Our results demonstrate the potential of HPS as a suitable support for tailoring metal NPs properties and circumvent undesirable metal leaching. .

The dendron/dendrimer size was found to strongly influence properties of catalysts based on such macromolecules. Here, we assessed the dendritic effect of third generation pyridylphenylene dendrons (G3) immobilized on magnetic silica and loaded with Pd species in Suzuki-Miyaura reactions of Br-arenes and phenylboronic acid as compared with the second generation dendron (G2) based catalyst. A comprehensive analysis allows decoupling the dendron influence from other parameters identifying a strong positive dendritic effect (higher activity with G3 based composite), attributed to a larger available space and to a greater number of coordinating groups in the G3 to host reacting molecules and stabilize catalytic species. A “local Pd leaching” mechanism for the Suzuki-Miyaura reaction, which occurs in the dendron environment of the catalyst, provides an excellent catalytic activity. This finding along with easy magnetic separation (a remarkable catalytic stability in five consecutive catalytic cycles) make such systems promising for other cross-coupling reactions.

Here we report immobilization of glucose oxidase (GOx) on magnetic silica (Fe3O4-SiO2) and alumina (Fe3O4-Al2O3) functionalized with amino groups using glutaraldehyde as a linker. Magnetic support based biocatalysts demonstrate high catalytic activity in d -glucose oxidation to D-gluconic acid at pH 5–7.5 and temperature of 30–50 °C with the best activities of 95% and 91% for magnetic silica and alumina, respectively. A comparison of magnetic and non-magnetic alumina and silica shows a significant enhancement of the relative catalytic activity for magnetic supports, while the silica based biocatalysts show a higher activity than the biocatalysts based on alumina. A noticeably higher activity of GOx immobilized on magnetic supports is explained by synergy of the GOx inherent activity and enzyme-like activity of iron oxide nanoparticles, while the enhancement with silica based catalysts is most likely due to a larger pore size and stronger Bronsted acid sites. Excellent relative activity of Fe3O4-SiO2-GOx (95% of native GOx) in a tolerant pH and temperature range as well as high stability in a repeated use (6% relative activity loss after five catalytic cycles) makes this catalyst promising for practical applications.

In this paper, theoxidation process of 2 -methylnaphthalene to vitamin K3, using a gold catalyst systems will be discussed. This catalysis process is based on the hypercrosslinked polystyrene, synthesized by the impregnation with solutions of precursors − HAuCl4·2H2O and Ph3PAuCl. The use of gold catalyst system, which has been synthesized using Ph3PAuCl, allows to obtain the main product − 2-methyl-1,4-naphthoquinone − with 72% yield.