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In recent years, Pd-containing catalytic systems for tandem processes have gained special attention due to their enhanced catalytic properties and their possibility of performing several reactions without the necessity of separating the intermediates. In this review, recent progress in Pd-catalyzed tandem processes is considered. Three types of catalytic systems are described: homogeneous catalysts (including immobilized Pd complexes); heterogeneous catalysts supported on oxides, MOFs, COFs, etc., with particular attention to the supports containing acid/base sites; and metal-enzyme catalysts for chemoenzymatic tandem processes applied in fine organic synthesis and biotechnology. For homogeneous Pd-catalyzed reactions, different tandem reactions were considered, i.e., cross-coupling, cyclization, carbonylation, isomerization, alkylation, arylation, etc. [ABSTRACT FROM AUTHOR]

Carbon materials are widely used in catalysis as effective catalyst supports. Carbon supports can be produced from coal, organic precursors, biomass, and polymer wastes. Biomass is one of the promising sources used to produce carbon-based materials with a high surface area and a hierarchical structure. In this review, we briefly discuss the methods of biomass-derived carbon supported catalyst preparation and their application in biodiesel production, organic synthesis reactions, and electrocatalysis. [ABSTRACT FROM AUTHOR]

The modification of fatty substrates using heterogeneous catalysts have extensive industrial application and has an emphatic position in a sustainable context. Herein ruthenium, nickel, cobalt and copper-doped ruthenium, supported on hypercrosslinked polystyrene (HPS) catalysts were prepared by wet impregnation, characterized and applied on the modification of canola fatty acid methyl esters (FAME). The characterization showed a dispersive effect of doping metals over the ruthenium particles, the presence of acid sites and overall surface morphology, which allows targeting potential applications. The chosen modifications consisted of hydrogenation, hydroformylation, oxidative cleavage and deoxygenation, resulting in superb catalytic activities of over 99% conversions for hydrogenation and deoxygenation. The simplicity of the canola FAME composition allows the understanding of the catalytic processes and allows the upscale of more complex FAME matrixes. Finally, the obtained data stimulates further optimization studies for each application with a variation on the catalysts and the usage of residual fatty substrates, greatly enhancing the sustainability profile of the systems. [ABSTRACT FROM AUTHOR]

During the last decades, palladium nanoparticles (Pd(0) NPs) and Pd(II) compounds were shown to be attractive catalysts for fine organic synthesis. Nanostructured Pd(0) or Pd(II) catalysts have a relatively low environmental impact, but, at the same time, they are indispensable for such processes as Suzuki cross-coupling. This paper describes the preparation of Pd(0) or Pd(II) supported/embedded in hyper-cross-linked polystyrene (HPS) and compares their activity in Suzuki cross-coupling between phenylboronic acid and 4-bromoanisole. Obviously, the palladium charge (Pd(0) ↔ Pd(II)) changes continuously during the reaction catalytic cycle. It would seem that the use of the starting palladium in the form of Pd(0) or Pd(II) should not affect the reaction's kinetic laws for both catalysts, but their special individuality is manifested between them. Nanoparticulate Pd(0) catalysts are stable during the reaction. In contrast, catalysts based on Pd(II) are extremely active in the initial period of the reaction, but then the "hot form" of the catalyst is rapidly converted into the form of Pd(0), whose activity is identical to that of the preliminarily reduced catalyst. This work discusses the possible nature of this phenomenon. A mathematical model for Suzuki cross-coupling reaction was suggested that was able to adequately describe experimental data. The level of reliability (R2) of the correlation between the experimental and calculated data was R2 = 0.97–0.99. [ABSTRACT FROM AUTHOR]

Nowadays, the processes for the conversion of biomass to fuels are of great interest. One of the widely studied reactions is the deoxygenation of oxygen-containing compounds. The process is performed in two main directions: in hydrogen presence (namely hydrodeoxygenation) and using supercritical fluids as a hydrogen source. The modern problem in deoxygenation is catalyst stability and selectivity. Thus, the development of novel catalytic systems is an urgent task. Schungite is a natural carbon-reach material that has high sorption ability and excellent reductive properties. These properties make this material suitable for its use as catalyst support. In this work, the study of the effectiveness of novel schungite-based catalysts in supercritical deoxygenation of fatty acids and bio-oil model compounds is presented. The catalyst synthesis was performed by the recently developed method of Ni hydrothermal deposition on the schungite surface. The synthesized catalysts were tested in the deoxygenation of stearic acid and guayacol in the supercritical hexane. The experimental results showed that the developed catalysts allow 100 % conversion of the substrate to be reached in both processes providing over 90 wt.% of gasoline and diesel-range hydrocarbon yield. [ABSTRACT FROM AUTHOR]

Alkane production from fatty acids and their derivatives can be considered one of the most‐studied processes. Such reactions as hydrogenation, hydrodeoxygenation, decarboxylation, and decarbonylation are the main routes for this process. The reaction pathway depends on the nature of the catalyst, the presence of hydrogen, and the hydrogen source. In this work, a mixture of unsaturated fatty acids (oleic and linoleic acids) was converted to alkanes (mainly heptadecane) in a hydrogen‐free atmosphere by using 2‐propanol as hydrogen donor. Transition metal doped Pd catalysts embedded on a porous organic support (hypercrosslinked polystyrene) were used as catalysts. A Pd‐Cu catalyst showed the highest effectiveness, allowing up to 99.9 mol % selectivity to heptadecane to be obtained. The process proceeds through fatty acid esterification, further hydrogenation of double bonds, and decarboxylation to form n‐heptadecane as main product. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The search of the novel stable and active catalysts for the Fischer-Tropsch synthesis aimed at the formation of gasoline-range hydrocarbons is one of the main directions for the production of liquid transportation fuels from the alternative feedstock. The stabilization of the active phase is one of the key challenges for the development of the catalysts of CO hydrogenation into liquid motor fuel. This problem can be solved by the choice of optimal support as well as the method of synthesis. The rigid polymeric matrices allow obtaining highly effective and stable metal-containing nanoparticles characterized by the high surface area and enhanced activity. A hydrothermal deposition is a promising way to produce catalysts with the high dispersion of the active phase avoiding the pore blockage by the metal-containing particles. The current work is devoted to the development of novel polymer-based mono- and bimetallic Co-, Ni-, and Ru-containing nanocatalysts for the liquid-phase Fischer-Tropsch synthesis. It was shown that 1% Ru-HPS and 10% Co-1% Ru-HPS allow obtaining a high yield of gasoline-range C5-C9 hydrocarbons (over 70%) providing high CO conversion (up to 23%). The chosen polymer-based systems showed high stability in the FTS process. The activity loss was found to be insignificant for both catalysts (3.2% for 1% Ru-HPS, and 8.2% for 10% Co-1% Ru-HPS) after 20 h of the process. [ABSTRACT FROM AUTHOR]

Deposition of catalytically active metal‐containing compounds on solid porous supports by using superheated (subcritical) water is a promising way to produce materials with unique physicochemical and catalytic properties. The hydrothermal method has been found to give catalysts with high surface area, fine distribution of the active phase, and high catalytic activity. In the current work, the catalytic activities of 10 % Ni and 10 % Co deposited on hyper‐cross‐linked polystyrene (HPS) by the hydrothermal method in the supercritical deoxygenation of fatty acids were compared. 10 % Ni/HPS was found to be the most active catalyst in the deoxygenation of stearic acid in supercritical n‐hexane. Supported metal catalysts play an important role in chemical technology, and hydrothermal synthesis of catalysts has recently attracted much attention. Cobalt and nickel nanoparticles were deposited on a hyper‐cross‐linked polystyrene matrix by a hydrothermal method, and the catalytic activity of the resulting catalysts was evaluated in the deoxygenation of fatty acids in supercritical n‐hexane. [ABSTRACT FROM AUTHOR]

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 gammavalerolactone (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%). [ABSTRACT FROM AUTHOR]

Influence of heterogenization on catalytic properties of block copolymer micellar catalysts derived from polystyrene-block-poly-4-vinylpyridine and containing Pd monometallic and bimetallic PdAu, PdPt, and PdZn nanoparticles has been studied in selective hydrogenation of the triple bond of 3,7-dimethyloctaen-6-yne-1-ol-3 (dehydrolinalool). We demonstrate that the heterogenization can both increase and decrease catalytic activity depending on the type of NPs. In the absence of a modifying metal (Pd monometallic nanoparticles) or for PdZn nanoparticles where Zn is the electron donor, the activity of heterogenized catalysts increases, while for PdAu and PdPt based catalysts, where the modifying metal is the electron acceptor, the activity decreases. These changes are explained by the increased polarity of the catalyst after deposition on alumina (addition of a component with a higher dielectric constant) offset by poor accessibility of some catalytic sites of nanoparticles containing electron deficient Pd atoms. [Copyright &y& Elsevier]

This work is addressed to the phenomenon of catalyst deactivation taking place during the repeated uses in the reaction of Suzuki-Miyaura (S-M) cross-coupling, which is widely applied in industry for C-C bond formation. Ligandless catalysts based on Pd(0) NPs supported on hyper-cross-linked polystyrene (HPS) of two types (non-functionalized and bearing tertiary amino groups) were studied in a model S-M reaction between 4-bromoanisole and phenylboronic acid. Synthesized catalysts were shown to be highly active under mild reaction conditions. HPS allows stabilization of Pd(0) NPs and prevents their agglomeration and detectable Pd leaching. However, the loss of catalytic activity was observed during recycling. The deactivation issue was assigned to the hydrophobic nature of non-functionalized HPS, which allowed a strong adsorption of cross-coupling product during the catalyst separation procedure. A thorough washing of Pd/HPS catalyst by hydrophobic solvent was found to improve to the big extent the observed catalytic activity, while the replacement of non-functionalized HPS by a one containing amino groups increased the catalyst stability at the expense of their activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Polymeric silica-containing catalysts were developed for anthracene hydrocracking. • Two different methods for the polymer surface modification by silica were applied. • The catalysts are characterized by the high surface area, bimodal pore size distribution and high acidity. • The synthesized Ni-SiO 2 -MN-270 catalysts provide over 80 % of anthracene conversion into monoaromatics. In this work, novel bifunctional catalysts based on the polymeric network of hypercrosslinked polystyrene were developed for the process of anthracene hydrocracking in the medium of supercritical propanol-2. The synthesized catalysts contain NiOOH as an active phase and the SiO 2 as Brønsted acid sites supported on the highly porous support. The influence of the synthesis method and silica precursor type on the textural properties and the active phase composition was studied. The catalyst obtained by the hydrothermal method using tetraethoxysilane as a silica precursor seems to be the most optimal providing both high surface area, bimodal pore size distribution, and high acidity, and, thus, higher catalytic activity in anthracene hydrocracking. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel bimetallic Ru-Co polymeric catalysts were synthesized. • Hydrogenation of levulinic acid was studied at variation of reaction conditions. • Impregnation of Co resulted in Ru redistribution inside the polymeric support. 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 RuO 2 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. [ABSTRACT FROM AUTHOR]