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The development of supporting materials based on carbon nanotubes (CNTs) impregnated with iron nanoparticles via a sustainable and green synthesis employing plant extract of Punica granatum L. leaves was carried out for the iron nanoparticle modification and the following impregnation into the carbon nanotubes composites (CNT-Fe) that were also coated with polypyrrole (CNT-Fe + PPy) for use as electrode for supercapacitor and triboelectric nanogenerators. The electrochemical characterization of the materials by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) assays revealed that the CNT-Fe + PPy gave rise to better performance due to the association of double-layer capacitance behavior of carbon derivative in association with the pseudocapacitance contribution of PPy resulting in an areal capacitance value 202 mF/ cm2 for the overall composite. In terms of the application of electrodes in triboelectric nanogenerators, the best performance for the composite of CNT-Fe + PPy was 60 V for output voltage and power density of 6 μW/cm2. The integrated system showed that the supercapacitors can be charged directly by the nanogenerator from 0 to 42 mV in 300 s. The successful green synthesis of iron nanoparticles on CNT and further PPy coating provides a feasible method for the design and synthesis of high-performance SCs and TENGs electrode materials. This work provides a systematic approach that moves the research front forward by generating data that underpins further research in self-powered electronic devices. [ABSTRACT FROM AUTHOR]

One-pot depolymerisation of lignin, extracted from Miscanthus plants under acidic (formic acid lignin, FAL) or basic (ammonia lignin, AL) conditions, over Ni- and/or Nb-doped SBA-15, was the subject of this study. The aforementioned acid catalysts prepared by sol–gel method were characterized by SEM–EDX, ATR-FTIR, Raman, XRD, N2 adsorption/desorption isotherms, CO2-TPD and NH3-TPD techniques. The increase in acidity due to the insertion of Nb into the SBA-15 structure promoted the selective cleavage of β–O–4 from ammonia lignin, leading to aromatic monomer yields up to 22 wt% in 6 h at 180 °C under 50 atm H2. The catalytic performances of Ni-Nb-SBA-15 as well as its stability were influenced by the chemical composition of the lignin sample as results of its extraction from the Miscanthus plant. [ABSTRACT FROM AUTHOR]

Hardwood spent mushroom substrate was employed as a carbon precursor to prepare activated biochars using phosphoric acid (H3PO4) as chemical activator. The activation process was carried out using an impregnation ratio of 1 precursor:2 H3PO4; pyrolysis temperatures of 700, 800, and 900 °C; heating rate of 10 °C min−1; and treatment time of 1 h. The specific surface area (SSA) of the biochars reached 975, 1031, and 1215 m2 g−1 for the samples pyrolyzed at 700, 800, and 900 °C, respectively. The percentage of mesopores in their structures was 75.4%, 78.5%, and 82.3% for the samples pyrolyzed at 700, 800, and 900 °C, respectively. Chemical characterization of the biochars indicated disordered carbon structures with the presence of oxygen and phosphorous functional groups on their surfaces. The biochars were successfully tested to adsorb acetaminophen and treat two simulated pharmaceutical effluents composed of organic and inorganic compounds. The kinetic data from adsorption of acetaminophen were fitted to the Avrami fractional-order model, and the equilibrium data was well represented by the Liu isotherm model, attaining a maximum adsorption capacity of 236.8 mg g−1 for the biochar produced at 900 °C. The adsorption process suggests that the pore-filling mechanism mainly dominates the acetaminophen removal, although van der Walls forces are also involved. The biochar produced at 900 °C removed up to 84.7% of the contaminants in the simulated effluents. Regeneration tests using 0.1 M NaOH + 20% EtOH as eluent showed that the biochars could be reused; however, the adsorption capacity was reduced by approximately 50% after three adsorption–desorption cycles. [ABSTRACT FROM AUTHOR]

Mesoporous SBA-15 silicate with a high surface area was prepared by a hydrothermal method, successively modified by organic melamine ligands and then used for deposition of Pd nanoparticles onto it. The synthesized materials were characterized with infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), nitrogen physisorption, scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) and inductively coupled plasma (ICP-OES). The catalyst was effectively used in the Mizoroki–Heck coupling reaction of various reactants in the presence of an organic base giving the desired products in a short reaction time and with small catalysts loadings. The reaction parameters such as the base type, amounts of catalyst, solvents, and the temperature were optimized. The catalyst was easily recovered and reused at least seven times without significant activity losses. [ABSTRACT FROM AUTHOR]

Hydrothermal deoxygenation of tall oil fatty acids (TOFA) was investigated in the presence of aqueous formic acid (0.5–7.5 wt%) as a H2 donor in the presence of subcritical H2O pressure (569–599 K). Pd and Ru nanoparticles supported on carbon (5% Pd/CSigma, 5% Ru/CSigma, 10% Pd/CO850_DP, and 5% Ru/COPcomm_DP) were found to be efficient catalysts for deoxygenation of TOFA. The reaction pathway was mainly influenced by the concentration of formic acid and the catalyst. In case of Pd catalysts, in the presence of 0–2.5 wt% formic acid, decarboxylation was the dominant pathway producing n-paraffinic hydrocarbons with one less carbon atom (heptadecane yield up to 94 wt%), while with 5–7.5% formic acid, a hydrodeoxygenation/hydrogenation mechanism was favored producing C18 deoxygenation products octadecanol and octadecane as the main products (yields up to 70 wt%). In contrast, Ru catalysts produced a mixture of C5-C20 (n-and iso-paraffinic) hydrocarbons via decarboxylation, cracking and isomerization (up to 58 wt% C17 yield and total hydrocarbon yield up to 95 wt%) irrespective of formic acid concentration. Kinetic studies showed that the rates of deoxygenation displayed Arrhenius type behavior with apparent activation energies of 134.44 ± 31.36 kJ/mol and 148.92 ± 3.66 kJ/mol, for the 5% Pd/CSigma and 5% Ru/CSigma catalyst, respectively. Furthermore, the experiments with glycerol tristearate, rapeseed oil, sunflower oil, rapeseed biodiesel, and hydrolyzed rapeseed oil produced identical products confirming the versatility of the aforementioned catalytic systems for deoxygenation of C18 feedstocks. [ABSTRACT FROM AUTHOR]

Magnetic particles were prepared by a hydrothermal method and then successively covered by Metal–Organic-Frameworks MIL-101-NH2 with a high surface area. This was followed by deposition of Pd(OAc)2 on Fe3O4–NH2@MIL-101-NH2 particles. The final catalyst was characterized with FT-IR, nitrogen physisorption, thermogravimetry (TGA), scanning electron microscopy (SEM) combined with energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), wide-angle X-ray diffraction spectroscopy (XRD) and X-ray photoelectron spectroscopy (XPS). The prepared magnetic catalyst was effectively used in the Heck coupling reaction in the presence of an inorganic base. The reaction parameters such as the base type, amounts of catalyst and solvents, temperature, and substrates ratios were optimized. The catalyst was then magnetically separated, washed, and reused 7 times without losing significantly catalytic activity. [ABSTRACT FROM AUTHOR]

IRMOF-3 with a high surface area prepared by a hydrothermal method was used for deposition of Pd(OAc)2 on IRMOF-3 particles. The final catalyst was characterized with FT-IR, nitrogen physisorption, thermogravimetry, scanning electron microscopy, transmission electron microscopy combined with energy dispersive X-ray analysis, wide angle X-ray diffraction spectroscopy and X-ray photoelectron spectroscopy. The prepared porous catalyst was effectively used in the Heck coupling reaction in the presence of an organic base. The reaction parameters such as the type of base, amounts of catalyst and solvents, temperature were optimized. The catalyst was then easily separated, washed, and reused 4 times without significant losses of catalytic activity. [ABSTRACT FROM AUTHOR]

Owing to their higher intrinsic electrical conductivity and chemical stability with respect to their oxide counterparts, nanostructured metal sulfides are expected to revive materials for resistive chemical sensor applications. Herein, we explore the gas sensing behavior of WS2 nanowire-nanoflake hybrid materials and demonstrate their excellent sensitivity (0.043 ppm-1) as well as high selectivity towards H2S relative to CO, NH3, H2, and NO (with corresponding sensitivities of 0.002, 0.0074, 0.0002, and 0.0046 ppm-1, respectively). Gas response measurements, complemented with the results of X-ray photoelectron spectroscopy analysis and first-principles calculations based on density functional theory, suggest that the intrinsic electronic properties of pristine WS2 alone are not sufficient to explain the observed high sensitivity towards H2S. A major role in this behavior is also played by O doping in the S sites of the WS2 lattice. The results of the present study open up new avenues for the use of transition metal disulfide nanomaterials as effective alternatives to metal oxides in future applications for industrial process control, security, and health and environmental safety. [ABSTRACT FROM AUTHOR]

High-latitude soils store ~40% of the global soil carbon and experience winters of up to 6 months or more. The winter soil CO2 efflux importantly contributes to the annual CO2 budget. Microorganisms can metabolize short chain carbon compounds in frozen soils. However, soil organic matter (SOM) is dominated by biopolymers, requiring exoenzymatic hydrolysis prior to mineralization. For winter SOM decomposition to have a substantial influence on soil carbon balances it is crucial whether or not biopolymers can be metabolized in frozen soils. We added 13C-labeled cellulose to frozen (−4 °C) mesocosms of boreal forest soil and followed its decomposition. Here we show that cellulose biopolymers are hydrolyzed under frozen conditions sustaining both CO2 production and microbial growth contributing to slow, but persistent, SOM mineralization. Given the long periods with frozen soils at high latitudes these findings are essential for understanding the contribution from winter to the global carbon balance. [ABSTRACT FROM AUTHOR]

The incentives for utilizing a versatile range of renewable feedstocks in novel ways are continuously increasing. Sulfated polysaccharides from green algae, such as ulvan, are interesting due to the rare sugar constituents which can be utilized for new materials and chemicals in industry. However, before valorization fractionation needs to be performed in a controlled way. In the current work, the kinetics of the aqueous extraction of ulvan was studied in the temperature range 60-130 °C. The highest yield of 97.6 wt.% was attained after 2 h of extraction at 130 °C, and the extraction efficiency was observed to be heavily temperature dependent. Interestingly, two regimes of extraction kinetics were observed, presumably due to the different ulvan fractions contained within the cell wall of green algae. The experimental data was modeled with first-order kinetics, and an apparent activation energy of 53.8 kJ mol was obtained for the process. The algal residue was processed using simultaneous saccharification and fermentation, and 0.48 g ethanol g of sugars was obtained. [ABSTRACT FROM AUTHOR]

Use of switchable ionic liquid (SIL) pulp offers an efficient and greener technology to produce nanofibers via ultrafine grinding. In this study, we demonstrate that SIL pulp opens up a mechanically efficient route to the nanofibrillation of wood pulp, thus providing both a low cost and chemically benign route to the production of cellulose nanofibers. The degree of fibrillation during the process was evaluated by viscosity and optical microscopy of SIL treated, bleached SIL treated and a reference pulp. Furthermore, films were prepared from the fibrillated material for characterization and tensile testing. It was observed that substantially improved mechanical properties were attained as a result of the grinding process, thus signifying nanofibrillation. Both SIL treated and bleached SIL treated pulps were fibrillated into nanofibers with fiber diameters below 15 nm thus forming networks of hydrophilic nature with an intact crystalline structure. Notably, it was found that the SIL pulp could be fibrillated more efficiently than traditional pulp since nanofibers could be produced with more than 30% less energy when compared to the reference pulp. Additionally, bleaching reduced the energy demand by further 16%. The study demonstrated that this switchable ionic liquid treatment has considerable potential in the commercial production of nanofibers due to the increased efficiency in fibrillation. [ABSTRACT FROM AUTHOR]

Herein, one-pot conversion of cellulose to platform chemicals, formic and levulinic acids was demonstrated. The catalyst selected was an affordable, acidic ion-exchange resin, Amberlyst 70, whereas the cellulose used was sulfite cellulose delivered by a Swedish pulp mill. Furthermore, in an attempt to better understand the complex hydrolysis network of the polysaccharide, kinetic experiments were carried out to pinpoint the optimal reaction conditions with an initial substrate concentration of 0.7-6.0 wt% and a temperature range of 180-200 °C. Higher temperatures could not be used due to the limitations in the thermal stability of the catalyst. Overall, maximum theoretical yields of 59 and 68 mol% were obtained for formic and levulinic acid, respectively. The parameters allowing for the best performance were reaction temperature of 180 °C and initial cellulose concentration of 0.7 wt%. After studying the behavior of the system, a simplified reaction network in line with a mechanistic approach was developed and found to follow first order reaction kinetics. A satisfactory fit of the model to the experimental data was achieved (97.8 % degree of explanation). The catalyst chosen exhibited good mechanical strength under the experimental conditions and thus, a route providing green platform chemicals from soft wood pulp from coniferous trees (mixture of Scots Pine and Norway Spruce) was demonstrated. [ABSTRACT FROM AUTHOR]

-SOH containing carbon materials (sulfonated carbons) were successfully employed as heterogeneous catalysts upon the selective esterification of glycerol with lauric and oleic acids. The functionalized carbon catalysts outperformed zeolites H-Y, H-ZSM-5 and liquid HSO with respect to activity and selectivity, thus producing commercially important monoglycerides with excellent selectivity (70-80 %), at fatty acid conversion levels of 80-95 %. Most importantly, upon use of these catalysts, significant improvements were obtained with respect to process parameters in comparison to the solid acids reported before: our reaction (1) required shorter reaction time (7-24 h), (2) operated at equimolar fatty acid-to-glycerol ratio, (3) could be employed at moderate reaction temperatures (100-125 °C) and (4) catalyst reused was feasible thus confirming the catalytic potential of sulfonated carbons for production of high concentration monoglycerides. Moreover, the experimental results also demonstrate the existence of strong effects of catalyst pore structure (shape selectivity) and surface hydrophilicity imposed to the reaction products similar to the reactivity selectivity trends observed for -SOH functionalized silica catalysts reported in previous studies. [ABSTRACT FROM AUTHOR]

In this work the activity of ruthenium decorated carbon foam (Ru/CF) catalyst was studied in three phase hydrogenation reaction of d-xylose to d-xylitol. The developed catalyst was characterized by using scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, inductively coupled plasma optical emission spectrometry and nitrogen adsorption-desorption measurement. Kinetic measurements were carried out in a laboratory scale pressurized reactor (Parr) assisted by SpinChem rotating bed reactor (SRBR), at pre-defined conditions (40-60 bar H and 100-120 °C). The study on the influence of reaction conditions showed that the conversion rate and selectivity of hydrogenation reaction of d-xylose was significantly affected by temperature. These results have been proved by a competitive kinetics model which was found to describe the behavior of the novel system (Ru/CF catalyst used together with the SRBR) very well. Besides, it was revealed that the catalytic activity as well as the stability of our Ru/CF-SRBR is comparable with the commercial ruthenium decorated carbon catalyst (Ru/AC) under identical reaction conditions. Moreover, all steps from catalyst preparation and catalyst recycling as well as catalytic testing can be performed in an easy, fast and elegant manner without any loss of materials. Briefly, the developed Ru/CF catalyst used together with the SRBR could be used an excellent alternative for the conventional Raney nickel catalyst in a slurry batch reactor and offers an attractive concept with obvious industrial applicability. [ABSTRACT FROM AUTHOR]

Nanosized metal (Pt or Pd)-decorated TiO nanofibers (NFs) were synthesized by a wet impregnation method. CdSe quantum dots (QDs) were then anchored onto the metal-decorated TiO NFs. The photocatalytic performance of these catalysts was tested for activation and reduction of CO under UV-B light. Gas chromatographic analysis indicated the formation of methanol, formic acid, and methyl formate as the primary products. In the absence of CdSe QDs, Pd-decorated TiO NFs were found to exhibit enhanced performance compared to Pt-decorated TiO NFs for methanol production. However, in the presence of CdSe, Pt-decorated TiO NFs exhibited higher selectivity for methanol, typically producing ∼90 ppmg·h methanol. The CO photoreduction mechanism is proposed to take place via a hydrogenation pathway from first principles calculations, which complement the experimental observations. [ABSTRACT FROM AUTHOR]

Metal nanoparticles supported on surfaces often undergo sintering even at moderate temperatures. The degree of sintering is typically influenced by the surface chemistry indicating that besides the commonly believed Ostwald ripening also other processes associated with metal surface diffusion are responsible for the nanoparticle size growth. In addition to the deterioration in metal dispersion, carbon supports can show chemical instability leading to their partial degradation in the proximity of the nanoparticles both in reducing and oxidizing environments at elevated temperatures. This work reports a study of Pd, Pt and Ni nanoparticles anchored on carbon (activated carbon, graphite and carbon nanotubes) as well as titania (nanoparticles and microparticles) surfaces frequently applied as catalyst materials in heterogeneous catalysis and photocatalysis, and evaluate the potential events causing metal sintering and degradation of the supports using transmission electron microscopy analysis. [ABSTRACT FROM AUTHOR]

The isomerisation of α-pinene oxide to campholenic aldehyde, an expensive ingredient utilized by e.g. flavor industry, was studied over Supported Ionic Liquid Catalysts (SILCAs) consisting of catalytically active species residing in ionic liquid. The ionic liquid, in turn, was immobilized on a solid support material. SILCAs were demonstrated as efficient catalysts for the transformation of α-pinene oxide into campholenic aldehyde, with the product distribution and activity being dependent on the nature of the ionic liquid. [ABSTRACT FROM AUTHOR]

In this study, a set of nitrogen-doped TiO-based nanomaterials demonstrating photocatalytic activity was developed by combining the efforts of lattice doping and metal nanoparticle decoration and tested for photo-degradation of methylene blue dye by applying solar simulator irradiation. The surface potential shifts of these TiO-based photocatalytic nanomaterials measured by Kelvin probe force microscope have been used to study the degree of electron generation of the photocatalysts after irradiation and were well correlated with the photocatalytic activity. The nitrogen-doped TiO nanowires decorated with Pt nanoparticles can induce obvious electron accumulation and result in a large shift of surface potential. The analysis shows a clear correlation between the surface potential shift and the photodegradation activity. Furthermore, a thorough comparative photocatalytic activity study combined with X-ray photoelectron spectroscopy analysis of the materials-doped with nitrogen under various conditions-reveals that the photocatalytic efficiency of the catalysts is maintained even if the lattice doping is leached e.g., by thermal treatments after doping. Graphical Abstract: By monitoring the surface potential shifts of various TiO-based photocatalysts by photo-assisted Kelvin probe force microscopy, we obtain a useful tool for developing novel materials with high photocatalytic activity.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The aim of this work was to study the how various heterogeneous catalysts perform upon lignosulfonate decomposition reactions. The main target of the study was to obtain extractable phenolic compounds as potential renewable chemicals for the production of fuel components and chemicals. The nature of the heterogeneous catalyst was found to have a great impact on the obtained product yields and the composition of the product mixture. Initially, a nickel-tungsten on alumina (NiW/AlO) reference catalyst was applied upon screening the influence of catalyst particle size and various reaction parameters. Significantly increasing product yields with decreasing catalyst particle size indicated that the lignosulfonate transformation takes place on the external catalyst surface due to large macromolecular structure of the feedstock. The contact time (space time velocity) and catalyst particle size were the most important factors influencing the selectivity profiles towards various products as well as the yields observed. The highest conversion to phenolics was obtained over in-house-prepared NiO/AlO and NiMo/AlO catalysts with various NiO and MoO loadings. [ABSTRACT FROM AUTHOR]

Interconversion of lactulose to lactulose with the aim to determine and optimize the yield of ketose was carried out. Various homogenous and heterogeneous alkaline catalysts were applied (NaOH, MgO, hydrotalcite etc.). The selectivity and activity of the catalysts were compared. The results gave insight to the performance differences among the screened catalysts under the various reaction conditions. From the activity performance point of view, the conversion was limited by the formation of acidic end-products. In general, the selectivity decreased with conversion and the conversion-selectivity pattern was independent of the catalyst. [ABSTRACT FROM AUTHOR]

Pd and PdAu catalysts supported on SBA15 and SiO were prepared and investigated for HO direct synthesis in a batch autoclave (10 °C and 17.5 bar) and in the absence of halides and acids. The SiO supported catalysts exhibited inferior performances compared to the mesoporous ordered SBA15. A good control of both the catalysts dispersion and nanoparticle stability was achieved using SBA15. Catalysts were doped with bromine, a promoter in the HO direct synthesis. Productivity and selectivity decreased when bromine was incorporated in the catalysts, thus indicating a possible poisoning due to the grafting process. A synergetic effect between Pd and Au was observed both in presence and absence of bromopropylsilane grafting on the catalyst surface. Three modifiers of the SBA15 support (Al, CeO and Ti) were chosen to elucidate the influence of the surface properties on metal dispersion and catalytic performance. Higher productivity and selectivity were achieved incorporating Al into the SBA15 framework, whereas neither Ti nor CeO improved HO yields. The enhanced performance observed for the Prau/Al-SBA15 catalysts was attributed to the increased number of Brønsted acid sites. A modification of this catalyst with bromine was confirmed to impair both productivity and selectivity, possibly due to the broader particle size distribution and the poor stability of the metal nanoparticles, as demonstrate by transmission electron microscopy (TEM) images. HO disproportionation was also investigated. A much slower reaction rate was observed compared to the HO production, suggesting that the major contributor in the process of HO destruction must be connected to the hydrogenation reaction. [ABSTRACT FROM AUTHOR]

In this work, ionic liquid (IL) modified H-Beta zeolites were prepared and the physicochemical properties of the catalysts were investigated. IL modified zeolites were applied in 5-hydroxymethylfurfural (HMF) etherification to tert-butoxymethylfurfural (tBMF) which is a potential (bio)diesel component. The best catalyst, IL-H-Beta-25, yielded at BMF selectivity of 76 % corresponding to a HMF conversion of 46 %. [ABSTRACT FROM AUTHOR]

Catalytic and thermal conversion of abietic acid was investigated in a laboratory scale high-pressure autoclave. Fractionation of crude tall oil produces rosin acids of which abietic acid is the main compound. Tall oil rosin acid, a forest product industry residue, is an abundant, inexpensive and chemically desirable feedstock for production of lighter hydrocarbons that can be used as diesel fuel additives. The carboxylic acid functionality of the main reactant, abietic acid, must first be removed, followed by double bond hydrogenation of the remaining aromatic rings. In this study, a number of catalytic and non-catalytic reaction steps in the conversion of abietic acid were investigated. The aim was to study hydrogenation and decarboxylation reactions of abietic acid in order to produce lighter hydrocarbons. The experiments were performed by using toluene as a solvent as well as with neat abietic acid, in the absence of any solvent. Hydrogenation of abietic acid to tetrahydroabietic acid in toluene was successfully performed over palladium on carbon catalyst at the temperature range of 100-200 °C and at 30 bar hydrogen pressure. Thermal non-catalytic decarboxylation of abietic acid in toluene takes place at 200-300 °C resulting in one main product. The hydrocarbon products were further hydrogenated under hydrogen pressure. Catalytic decarboxylation of abietic acid in toluene was achieved over 5 wt% Ru/C, giving a wider product distribution than thermal decarboxylation. [ABSTRACT FROM AUTHOR]

The use of carbon dioxide in the synthesis of chemicals, such as dimethyl carbonate (DMC), constitutes an environmentally attractive alternative to hazardous and toxic reagents. However, the direct synthesis of DMC from methanol and CO is characterized by low yields due to the reaction equilibrium and the thermodynamic limitations $$ \left( {\Updelta G_{298K}^{o} \; = \; + 2 6. 3 {\text{ kJ}}/{\text{mol}}} \right) $$. Alkoxide ionic liquids possessing alkylimidazolium and benzalkonium cations were prepared, characterised and tested together with ZrO-MgO catalyst for the synthesis of DMC from methanol and CO. By using the novel ionic liquid as additives, ca. 12% conversion of methanol, and 90% selectivity to DMC was obtained at 120 °C and 7.5 MPa. The water abstracting potential of the ionic liquids influenced the conversion of methanol and the selectivity to DMC. The alkoxide ionic liquids were recovered and reused in DMC synthesis without loss in activity and selectivity. Graphical abstract: Synthesis of DMC from CO and methanol catalysed by ZrO-MgO using ionic liquid alkoxides as water abstracting additives. Comparison of the fresh and regenerated ionic liquid at 120 °C. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Supported Ionic Liquid Catalysts (SILCA) designed by immobilization of catalytic species residing in an ionic liquid layer, which in turn was immobilized on a solid support, were applied on the selective hydrogenation of citral in a batch reactor and in a continuous reactor. Different ionic liquids with and without addition of acid modificators were studied in terms of the catalyst activity and product selectivity. Consequently, mechanistic kinetic models describing the differences in the activity and selectivity of the catalysts consisting different ionic liquids, were developed. [ABSTRACT FROM AUTHOR]

In the presence of ultrasound both the initial hydrogenation rate of 1-phenyl-1,2- propanedione and the enantiomeric excess of the main product, i.e. (R)-1-hydroxy- 1-phenylpropanone, increased by 75 % and 52 % in toluene, respectively, as compared to the silent hydrogenation. [ABSTRACT FROM AUTHOR]