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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]

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]

Nitrobenzene hydrogenation is a widely used process applied for aniline production. Nitrobenzene hydrogenation kinetics greatly depends on catalyst properties and structure therefore, its study can shed light on process particularities and catalyst properties. The article is devoted to study of nitrobenzene hydrogenation kinetics for monometallic Ni (18.4 wt.%) containing hypercrosslinked polystyrene and bimetallic Pd(0.5 wt.%), Ni(17.9 wt.%) containing hypercrosslinked polystyrene. Nitrobenzene concentration and hydrogen partial pressure influence was studied in a variety of conditions. Nitrobenzene hydrogenation over monometallic sample shows the formation of essential amounts of side products - nitrozobenzene and phenylhydroxylamine while for bimetallic sample direct formation of aniline was noticed. Langmuir-- Hinshelwood model was used to study reaction kinetics. A complex model including azobenzene, phenylhydrohylamine and aniline formation steps was developed for monometallic catalyst. The reaction model for bimetallic Ni, Pd catalyst contains only direct aniline formation reaction due to high process selectivity. Values of adsorption and reaction constants are higher for bimetallic catalyst that can explain its enhanced nitrobenzene hydrogenation rate. [ABSTRACT FROM AUTHOR]

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. [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]

Graphical abstract Highlights • Pd-containing nanoparticles were stabilized by hypercrosslinked polystyrene. • The structure and catalytic activity of Pd nanoparticles were found to be depended on the nature of the precursor. • Pd-containing nanoparticles stabilized by HPS showed high selectivity (more 85%) in the hydrogenation of FF to FA. Abstract We report the hydrogenation of furfural (FF) to furfuryl alcohol (FA) with Pd-containing catalysts stabilized by hypercrosslinked polystyrene (HPS). FF is one of the major ingredients of biooil produced by biomass pyrolysis, while FA is a source of value-added chemicals, thus, creating an effective path from biomass to important compounds. Different palladium precursors (PdCl 2 (CH 3 CN) 2 , Pd(CH 3 COO) 2) were used for the catalysts synthesis. The nature of the precursor influences the size of palladium nanoparticles. The TEM and SAXS data showed that when using PdCl 2 (CH 3 CN) 2 , a monomodal distribution of particles size with mean diameter 5.4 ± 1.2 nm was observed, whereas for Pd(CH 3 COO) 2 , multimodal particle size distribution with the mean particle sizes up to 13.8 ± 5.4 nm was observed. The comparison of the catalytic activities of Pd-containing catalysts indicated that the more disperse sample of palladium showed higher values of FF conversion and selectivity to FA because of small particles. [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]

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: NH 2 -HPS (MN-100) and SO 3 H-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. [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]

Kinetics of the selective hydrogenation of 2-methyl-3-butyn-2-ol (MBY) to 2-methyl-3-buten-2-ol (MBE) over Pd supported on hypercrosslinked polystyrene bearing amino-groups was studied at variation of the MBY-to-Pd ratio and reaction temperature. For the catalyst, containing 0.7 wt.% of Pd, optimal reaction conditions were found providing >98% of the MBE selectivity at 95% of the MBY conversion. Kinetic modeling and temperature variations as well as studies of a hydrogen consumption rate allowed us to suggest that a thermodynamic factor is most likely responsible for the high MBE selectivity. [ABSTRACT FROM AUTHOR]

Postimpregnation of Pd nanoparticles (NPs) stabilized within hyper-cross-linked polystyrene with sodium or potassium hydroxides of optimal concentration was found to significantly increase the catalytic activity for the partial hydrogenation of the C-C triple bond in 2-methyl-3-butyn-2-ol at ambient hydrogen pressure. The alkali metal hydroxide accelerates the transformation of the residual Pd(II) salt into Pd(0) NPs and diminishes the reaction induction period. In addition, the selectivity to the desired 2-methyl-3-buten-2-ol increases with the K- and Na-doped catalysts from 97.0 up to 99.5%. This effect was assigned to interactions of the alkali metal ions with the Pd NPs surfaces resulting in the sites' separation and a change of reactants adsorption. [ABSTRACT FROM AUTHOR]