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Dry reforming of methane (DRM) was investigated using Ni–M oxide catalysts prepared by solution combustion synthesis (SCS) and compared with Ni/α-Al2O3synthesized by impregnation. According to X-ray diffraction, fresh oxide Ni–La and Ni–Ce catalysts displayed low crystallinity, which was improved after DRM, accompanied by the appearance of metallic Ni. Ni–Ce–Al and Ni–La–Al catalysts formed, respectively, CeAlO3and LaAlO3phases during the reaction. For studied catalysts featuring low surface areas ranging from 3 to 12 m2/g, the average metal particle sizes were 12–32 nm according to transmission electron microscopy, with the particles growing larger with time-on-stream (TOS) apart from Ni–α-Al2O3. DRM tests were conducted for different TOSs, demonstrating that the highest CH4transformation rate was concomitant with the highest deactivation rate during 30 min of time-on-stream. The most stable performance in temperature stability experiments was demonstrated by the Ni–Ce–Al catalyst, for which, similar to other catalysts, the H2/CO ratio remained close to unity. In long-term stability tests, the Ni–Ce–Al catalyst displayed a 3.1-fold higher turnover frequency (TOF) compared with Ni–α-Al2O3, with no significant deactivation. The TOF values were comparable to the literature, highlighting the potential of SCS as an alternative approach for synthesis of DRM catalysts.

Dry reforming of methane (DRM) is a promising method to utilize two greenhouse gases, such as CH4and CO2, to produce synthesis gas. In the current work, both monometallic Ni and bimetallic Ni–Fe catalysts with different Fe/Ni molar ratios, synthesized by solution combustion synthesis (SCS) in DRM, were investigated using a feed ratio of CH4/CO2/Ar of 1:1:1 at 600–900 °C. The catalysts were characterized by several physicochemical techniques such as X-ray diffraction (XRD), scanning electron microscopy energy-dispersive X-ray (SEM-EDX) spectroscopy, transmission electron microscopy (TEM), CHNS, N2physisorption, H2-TPR, O2-TPO, NH3-TPD, and thermogravimetric analysis (TGA). One of the highest hydrogen yields of 81% was obtained at 93% conversion of CH4and 94% conversion of CO2for the bimetallic 15Ni–5Fe–30Al catalyst, which contained, according to XRD, NiAl2O4spinel and metallic Ni phases. The spinel phase was decomposed during the reaction, while the Ni3Fe alloy was formed. Catalysts with a higher Fe/Ni ratio exhibited lower conversion and contained an inactive FeAl2O4spinel. Rather stable yields of CO and H2were obtained in an experiment with 20 h time-on-stream.

The one-pot synthesis of menthol from citral in a continuous mode was investigated over three different types of extrudates, namely Ni supported on H-Beta-38 and extruded with attapulgite, Ni supported on attapulgite and extruded with H-Beta-38, and the extrudates, which were shaped after deposition of Ni on both H-Beta-38 and attapulgite in the powder form. These composite catalysts were characterized by X-ray diffraction, transmission and scanning electron microscopy, temperature-programmed reduction of H2, mechanical strength, and pyridine adsorption desorption. These three types of extrudates exhibited different metal particle sizes and acidity. The most promising catalyst in the one-pot menthol synthesis was Ni supported first on H-Beta-38 and then extruded with attapulgite giving a 45% yield of menthols in a trickle bed reactor. This catalyst exhibited 10 nm nickel particles and a rather high amount of strong Brønsted acid sites.

Methyl levulinate was selectively formed from glucose and methanol over a copper modified Beta zeolite bifunctional catalyst at 180 °C under argon atmosphere. The selectivity to methyl levulinate substantially exceeded previously reported in the open literature results. The copper modification was done through an ion-exchange method using a solution of copper nitrate, followed by drying and calcination of the catalyst. Copper modification changed the distribution of acid sites namely, less Brønsted and more Lewis sites were observed with FTIR using pyridine adsorption. Application of the proton form H-Beta-25 gave the methyl levulinate yield of ca. 89%, which could be elevated with the addition of copper, as the apparent selectivity exceeds 99%, assuming that methyl glucosides are eventually transformed to methyl levulinate. The non-acidic Cu/SiO2catalyst was completely inactive in methyl levulinate formation. Metal modification of Beta zeolite with Sn and Zn did not perform as well as Cu in the formation of methyl levulinate during glucose transformation.

A series of monometallic platinum and bimetallic platinum–rhenium catalysts supported on mesoporous carbon Sibunit, which is a type of mesoporous, microcrystalline carbon, were investigated for hydrodeoxygenation (HDO) of isoeugenol (IE) at 200–300 °C and 30 bar of H2, using dodecane as a solvent. Catalytic activity was tested in a batch reactor to screen the catalysts and, for comparison, also in the continuous mode. For batch experiments, complete conversion, and a high yield of the desired product, propylcyclohexane (PCH), were obtained for all bimetallic PtRe/Sibunit in 240 min, with the highest yield of PCH when Pt:Re ratio was 1:1 or 1:3. The results for Pt–Re (1:1) were reproducible, in terms of catalytic activity and reusability of catalysts, which showed no deactivation. Monometallic Pt catalysts displayed low activity. Continuous experiments were performed with PtRe(1:1)/Sibunit at 30 bar H2, 0.5 mL/min of the liquid flow, and temperatures between 75 °C and 200 °C. The distribution of products showed deoxygenation at higher temperatures, while at lower temperatures, mainly oxygenated products were formed. XPS results confirmed the presence of ReOx species, where an increase in the platinum loading resulted in a decrease in the fraction of ReOx species and subsequently lower PCH yield.

5-Hydroxymethylfurfural (HMF) is a biobased platform chemical that can be valorized into a spectrum of valuable products. In this report, supported Ir, Ir–Co, Ir–Ni, and Ir–Ru catalysts were investigated for this purpose. Only hydrogenation of HMF to 2,5-bis-(hydroxymethyl)furan (BHMF) occurred over all catalysts. The effect of the second metal (Co, Ni, and Ru) on Ir/SiO2was reflected by the kinetic constants being in the order Ir–Ni/SiO2> Ir–Co/SiO2> Ir–Ru/SiO2. The oxophilic nature of the secondary metal improved the catalytic performance of the bimetallic catalysts compared to the monometallic iridium catalyst (Ir/SiO2). Addition of HCOOH and H2SO4as cocatalysts is a strategy to reach one-pot conversion of HMF to 2,5-di-methylfuran (DMF). Over-hydrogenolysis products such as 2,5-dimethyltetrahydrofuran were formed when only H2SO4was added, giving higher activity compared to addition of HCOOH. Simultaneous presence of acids gave the highest HMF conversion, promoting esterification to 5-formyloxymethyl furfural and allowing the one-pot transformation of HMF to DMF. Thermodynamic analysis of HMF transformations revealed that both hydrogenation and dehydration steps are feasible.

The three-step reaction of citral to menthol was investigated in an autoclave and a trickle-bed reactor over Ru-MCM-41 catalysts in powder and shaped forms, respectively, with the same composition and controlled metal location. All catalysts were characterized in detail and the results were correlated with catalytic tests. Activity and selectivity were strongly affected by controlling the location of Ru in the powder catalyst applied in the batch experiments. The catalyst with the largest distance between the metal and acid sites, and at the same time, with the highest total acidity, i.e.with Ru deposited exclusively on a binder Bindzil, displayed the highest yield of menthols. In contrast, in the trickle-bed reactor with extrudates the Ru location was of almost no importance which is related to mass transfer. Comparison between batch and continuous experiments also revealed significant differences in the product distribution. The highest yield of the desired menthol of 6% with stereoselectivity of 66% was obtained at a residence time of 12.5 min after 3 h of time-on-stream over egg-shell extrudates with Ru distribution at the outermost layer, deposition of Ru on both H-MCM-41 and the binder Bindzil, and the smallest Ru particle size.

Condensation of (−)-isopulegol with acetone was investigated at 25–40 °C over clay based materials (K10, cloisite Na+and halloysite nanotubes) modified with sulfonic acid groups by one-pot sulfonation with chlorosulfonic acid or via organosilylation with 2-(4-chlrosulfonylphenyl)-ethyltrimethoxysilane. The target product was the Rdiastereomer of dimethyl-substituted octahydro-2H-chromen-4-ol with exhibits antiviral activity. The catalysts were characterized by a range of physico-chemical methods. The effect of the initial isopulegol concentrations on the yield of ketone-derived chromenols and the R/Sisomers ratio was studied for the first time. The best catalyst was a highly acidic, large pore K10-clay modified by sulfonic acid. Varying the initial concentration of the reagents allows to find a balance between dehydration by-products and a side etherification reaction. A high yield (73%) of the desired chromenols was reached using 0.52 mol/l initial (−)-isopulegol concentration after 240 min at 87% substrate conversion and reaction temperature 25 °C. The yield exceeded that of other previously reported in the open literature catalysts.

Cascade transformations of (±)-citronellal in a continuous mode were investigated over a bifunctional shaped ruthenium catalyst bearing metal clusters of the size 7–13 nm. Four types of Ru/H-MCM-41 extrudates (1.5 × 10 mm) containing 30% of Bindzil-50/80 colloidal silica binder were prepared varying in metal location and metal-to-acid ratio, while the concentration of Brønsted and Lewis acid sites and textural properties of the final extrudates were comparable. Catalytic tests were performed in the trickle-bed reactor under 70 °C, 10 bar of H2, and the initial reactant concentration in cyclohexane 0.086 mol L−1for the liquid residence time of 12.5 min. As a reactant, isopulegol, citronellol or (±)-citronellal was used. Metal location in extrudates has a significant effect on the catalytic activity and selectivity especially in terms of isopulegol isomers which content correlated with the metal-to-acid site ratio. Stereoselectivity to the desired (±)-menthol was 68–70%. The highest amount of the desired menthol, 32% yield, was obtained over extrudates where Ru was deposited on the catalytic support, i.e.with the shortest distance between the acid and metal sites, the lowest Brønsted acidity, the lowest Brønsted–Lewis acid sites ratio, the highest specific surface area and the narrowest range of the Ru particle size distribution.

Dehydrogenation of isobutane to isobutene over supported gallium oxide microspherical catalysts was investigated in a fluidized-bed reactor. A partially crystallized nanostructured aluminum hydroxide-oxide, which is a product of gibbsite centrifugal thermal activation (CTA) obtained using a CEFLAR technology, was used as a catalyst support. The structural and textural properties of Ga2O3/Al2O3catalysts were characterized by a range of techniques including XRD, N2-physisorption, TPD of NH3and CO2, IRS of adsorbed pyridine, and selective adsorption of a series of acid–base indicators. A Ga–Al oxide catalyst exhibited a stable performance close to activity of Cr–Al oxide catalysts not containing soluble hexavalent chromium. Upon addition of Cr2O3(6 wt % of Cr), in amounts lower than in an industrial chromia/alumina catalyst (10.9% Cr), and 1% ZrO2to 6%Ga/Al2O3catalytic activity in isobutane dehydrogenation reaches the performance of the industrial KDM catalyst (“Sintez”, Russia).

Citronellal cyclization was carried out in a continuous mode over H-beta-25 zeolite-based extrudates in a trickle-bed reactor at 35 °C and 10 bar of Ar. The physicochemical properties of zeolitic catalysts in the form of extrudates with a different diameter (1.4–3 mm) containing 30 wt % of a binder were correlated with the catalytic results. Alumina, aluminosilicate clay, and colloidal silica were used as binders. For extrudates with 1.4 mm in diameter, a significant decrease in the surface area, pore volume, and the total number of acid sites was observed in comparison to the values expected from a simple mechanical mixture of constituents. The specific surface area was similar, while the pore volume and mechanical strength decreased with increasing extrudate diameter. For all catalysts, conversion of citronellal and the yield of the desired pulegols decreased because of lower acidity and more prominent mass transfer with a size increase, while the selectivity ratio for different pulegols was similar. Overall, the effect of mass transfer on catalytic results in citronellal cyclization was larger than the effect of acidity. The yield of pulegols and the ratio of isopulegol ethers were correlated with strong Brønsted and strong Lewis acid sites, respectively. A proper selection of the binder and diameter of the extrudates plays a crucial role in the cyclization of citronellal.

Several ZSM-5 derived micro-mesoporous catalysts were investigated in Prins cyclisation of (–)-isopulegol with benzaldehyde acting as a reactant and a solvent for production of heterocyclic oxygen containing 2H-chromene derivatives including the tetrahydropyran structure and exhibiting biological activity. The investigated catalysts were characterized by nitrogen adsorption, ammonia temperature programmed desorption, adsorption-desorption of pyridine and 2,6-di-tert- butylpyridine with Fourier transform infrared spectroscopic control. For the Prins reaction performed at 70 °C, the highest yield of the desired product, equal to 67% at complete conversion of (–)-isopulegol, was obtained over a micro-mesoporous catalyst containing an optimum amount of strong acid sites and mesopores, being 12 fold larger than the size of the desired product.

Continuous cyclization of citronellal over zeolite-based extrudates was performed in a trickle-bed reactor at 35–70 °C and 10 bar of argon. Catalytic results were correlated with the physicochemical properties of the shaped catalyst prepared by extrusion of β or Y zeolites with binders. Rheological tests were used to elucidate the flow properties of a catalytic slurry and relate them with the extrusion performance. This study revealed that application of methylcellulose and bentonite binder modified the textural and acidic properties of the final extrudates. The main product was (−)-isopulegol at all temperatures with selectivity remaining quite constant with time-on-stream. The results illustrated that a binder such as bentonite cannot be considered inert. The mass-transfer limitations observed in extrudates did not significantly influence selectivity to the desired pulegols. This study also showed that a direct transfer of the batch reactor data to industrial continuous operation in citronellal cyclization is not straightforward.

The hydrodeoxygenation (HDO) of three different phenolic model compounds, isoeugenol, guaiacol and vanillin was investigated using Ir/ZrO2and Ni/ZrO2as heterogeneous catalysts. The catalysts were prepared by incipient wetness impregnation and characterized by transmission electron microscopy, nitrogen adsorption, FTIR pyridine adsorption–desorption. The organic material in the spent catalysts was analyzed by organic elemental analysis and thermogravimetry. The results revealed that in guaiacol HDO at 250 °C under 30 bar total pressure the main product was cyclohexanol with 36% yield over Ni/ZrO2while the total deoxygenation forming cyclohexane was limited to 2%. Ir/ZrO2exhibited higher HDO activity compared to Ni/ZrO2giving 14% yield of cyclohexane. Extensive formation of methane and ethane was also observed in guaiacol HDO. Hydrodeoxygenation of isoeugenol over Ir/ZrO2resulted in maximally 33% yield of propylcyclohexane due to a low liquid phase mass balance. The main products in vanillin HDO at 100 °C in water was vanillyl alcohol.

This paper demonstrates the catalytic potential of novel Na-lignosulfonate (LS) derived meso/macroporous solid protonic acids upon C–C coupling of bio-based furanics and carbonyl compounds. The materials demonstrated catalytic activity for solventless hydroxyalkylation/alkylation (HAA) of 2-methylfuran with furfural, acetone, butanal, cyclohexanone, levulinic acid and α-angelica lactone under mild reaction conditions (50–60 °C) producing branched-chain C12–C16 hydrocarbon precursors in yields approaching 96%. Moreover, the carbon materials exhibiting high total acidity (6–6.4 mmol g−1) outperformed sulfonic acid resins (Amberlyst®70, Amberlite®IR120 and LS resin), zeolites and liquid acids (p-toluenesulfonic acid, acetic acid and phenol). In fact, the most active carbocatalyst (60LS40PS350H+) exhibited the same turnover frequency as p-toluenesulfonic acid (186 h−1) upon furfural conversion but with an improved HAA product yield (up to 88%) and reusability, maintaining 98% of its original activity up to seven reaction cycles. The observed catalytic activity and operational stability of the LS derived acidic carbocatalysts were attributed to the strongly Brønsted acidic –SO3H groups covalently incorporated into their structural carbon framework and the promotional effects of hydrophilic surface functional groups (–COOH and –OH) favoring adsorption of oxygenated reactant molecules.

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. [ABSTRACT FROM AUTHOR]

For the first time, in this work, C18 fatty acid amidation with equimolar amounts of ethanolamine was studied both in the absence and presence of heterogeneous catalysts in hexane as a solvent at 180 °C. The products, saturated, and especially unsaturated fatty alkanol amides, which exhibit endocannabinoid activities, have been conventionally prepared using toxic and corrosive homogeneous catalysts. The results revealed that noncatalytic thermal amidation of stearic acid proceeding much faster for stearic than for oleic or linoleic acids. Furthermore, microporous H-Beta-150 was the most active catalyst. Mesoporous, H-MCM-41 with lower acidity was also active in oleic acid amidation, whereas more acidic, mesoporous H-MCM-36 gave lower yield due to formation of esteramides.

Optimization of bifunctional Ni catalysts was performed to enhance the catalytic performance in the one-pot synthesis of commercially valuable menthol from citral. The effect of nickel precursors (nitrate, chloride, acetate, and sulfate) and the addition of bentonite clay was investigated in citral transformations in a batch reactor at 70 °C and 10 bar hydrogen, demonstrating higher activity for the Ni-H-β-38-bentonite composite derived from a nickel nitrate precursor, which can be attributed to a higher surface area, optimal Brønsted to Lewis acidity and metal particle size, as well as the egg-shell distribution of Ni particles. H-β-38 impregnated with nickel nitrate, followed by calcination and reduction, was shaped with bentonite as a binder to give extrudates for exploring the citral transformations in the trickle-bed reactor at 50–70 °C and 10 bar hydrogen. The highest selectivity to the desired menthols of 45% was obtained with 70% stereoselectivity to the menthol isomer at 70 °C. The apparent activation energy for citral transformations to menthols of 18.6 kJ/mol indicated the presence of mass transfer limitations. Catalytic activity was linked with the physical-chemical properties, which were characterized by transmission electron microscopy, X-ray diffraction, temperature-programmed reduction, Fourier transform infrared spectroscopy with pyridine, N2physisorption, and inductively coupled plasma–optical emission spectrometry methods.

–SO3H 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 H2SO4with 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 –SO3H functionalized silica catalysts reported in previous studies.

Catalytic hydrodeoxygenation (HDO) of fatty acids has been investigated using different feedstocks for renewable diesel production. Two types of catalysts were studied: sulfur-free nickel supported on H-Y zeolites, γ-Al2O3and SiO2, and palladium supported on active carbon as a noble metal catalyst. Preliminary HDO experiments were carried out on these catalysts in a semi-batch reactor at 300 °C in H2under a total pressure of 30 bar for 6 h with stearic acid as a model for fatty acids. An in-depth comparative study of Ni/H-Y and Pd/C was performed in HDO of fatty acid methyl ester (FAME) obtained from the Chlorellamicroalga, tall oil fatty acids (TOFA) and animal fat. HDO experiments revealed that Ni/H-Y was a better catalyst for this process providing higher activity for different fatty acids. Ni supported on γ-Al2O3and SiO2provided complete conversion upon testing in HDO of stearic acid while total HDO over Pd/C was not reached.

Isomerization of verbenol oxide to (1R, 2R, 6S)-3-methyl-6-(prop-1-en-2-yl)cyclohex-3-ene-1,2-diol, which exhibits anti-Parkinson activity, has been investigated with large and medium pore zeolites, namely H-USY and H-ZSM-5 types of catalysts with different SiO2to Al2O3ratio in dimethylacetamide as a solvent. The catalysts were characterized with nitrogen adsorption, 27Al MAS NMR, pyridine desorption, XRD, SEM and TEM techniques. The main reaction product was the target diol with the highest selectivity of 52 % achieved with H-ZSM-5-23 (the last number corresponds to SiO2/Al2O3ratio) at 49 % conversion of verbenol oxide. The catalyst deactivation was, however, extensive with medium pore zeolites, compared to large pore zeolites. The second highest selectivities to diol with H-USY-80 and H-ZSM-5-80 were about 47–50 mol% at 100 and 78 % of conversion, respectively, achieved at 140 °C within 3 and 5 h. The other main products were the corresponding cyclopentylhydroxyketone and oxetane. A reaction mechanism was proposed.

Two-step treatment of birch chips (Betula pendula) was tested using diethanolamine (DEA)-1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU)-CO2-switchable ionic liquid (SIL), resulting in a 23% weight reduction in 24 h. The weight of the chips was reduced to 32% of their initial weight upon the second treatment with fresh SIL. SIL to wood ratio of 5:1, at 100°C for 24 h, without stirring, was applied in both steps. The relative amount of wood lignin reduced from 24% to 14% after two treatment cycles. The relative amount of cellulose of the undissolved fraction after SIL treatment increased from 43% (native birch wood) to 68% after the second cycle. Also, the undissolved material was efficiently fibrillated. The dissolved materials recovered from spent SIL, after treatment, contained high xylan content, about 90% of the total hemicelluloses, which was 85% of the recovered material. The powder X-ray diffraction (XRD) results revealed that the crystallinity of the undissolved material increased slightly, indicating dissolution of the amorphous material. Moreover, transformation of cellulose form I to form II in the remaining undissolved chips was not observed.

High selectivity (82 %) to 3-methyl-6-(prop-1-en-2-yl)cyclohex-3-ene-1,2-diol, a potent anti-Parkinson drug, was achieved in the isomerization of verbenol oxide at the conversion level of 96 % in N,N-dimethylacetamide at 140 °C over a metal modified zeolite, Fe-Beta-300 with SiO2to Al2O3ratio of 300. This catalyst exhibits both weak and medium strong Brønsted and Lewis acid sites.

The enantioselective hydrogenation of ethyl benzoylformate (EBF) to (R)-ethyl mandelate over (−)-cinchonidine (CD)-modified Pt/Al2O3catalyst in toluene in a semi-batch reactor was studied as a function of modifier concentration, reaction temperature, stirring rate and catalyst particle size. The kinetic results showed higher enantioselectivity and lower initial rates tending asymptotically to a constant value as the amount of modifier increased. The maximum enantiomeric excess (ee) and the initial hydrogenation rate or turnover frequency obtained under optimized conditions with an initial concentration of 5.6 mmol L−1EBF at 25 °C over 5% (w/w) Pt/Al2O3were 85% (modifier-to-surface Pt of 1.28) and 109 h−1(modifier-to-surface Pt of 0.16), respectively. Additionally, catalyst deactivation due to the presence of impurities in the feed was prominent in some cases; therefore activated carbon was used as a cleaning agent of the raw material to remove impurities prior to catalyst addition.

Acid hydrolysis of O-acetyl-galactoglucomannan (GGM), the main non-cellulosic polysaccharide in coniferous wood, was studied at 90 °C in the pH range of 0.5–2.0 using different acids (hydrochloric acid, sulfuric acid, trifluoroacetic acid, oxalic acid, and formic acid) as homogeneous catalysts and cation exchange resins (Smopex 101 and Amberlyst 15) as heterogeneous catalysts. The hydrolysis rate was exclusively dependent on the pH of the solution, but independent of the concentration and type of acid. Analysis of the formation rates of oligomers with DP 2–5 revealed that GGM hydrolysis occurs rather randomly. The final products were mannose, galactose, and glucose. In the beginning of the reaction, the formation of galactose was slightly faster than those of other sugars, since galactose is a side substituent to the glucose–mannose main chain of GGM. However, with longer reaction times, the formation rates of sugar monomers were correlated with their initial abundances in the polysaccharide. Autocatalytic kinetics was observed in the presence of the heterogeneous catalysts: an induction time was observed, after which the reaction proceeded with the same rates as with homogeneous acids. The autocatalytic effect is probably explained by the increase of the hydrolysis rate constant, as the GGM chain length decreases and the molecule becomes more accessible for the active sites on the outer surface of the catalyst.

Several Au/Al2O3catalysts were prepared and evaluated in the oxidation of l-arabinose. Metal cluster size was varied by application of different preparation methods (DPU and DIE), washing agents (ammonia or water), calcination temperatures, and concentrations of the initial precursor solutions. The structure sensitivity of the reaction over these catalysts was proven. A volcano relationship of activity with the mean particle size was observed, the catalyst prepared by DPU being the most active one. The catalyst electric potential was correlated with the particle size by an inverse volcano shape. At 30% of conversion, the DPU sample exhibited the lowest potential.

Kinetic resolution and dynamic kinetic resolution, in particular, provide practical tools for synthesis of enantiomerically pure compounds. In the present work, the resolution of rac‐2‐hydroxy‐1‐indanone and racemization of (S)‐2‐hydroxy‐1‐indanone were investigated. Immobilized lipase AK (Pseudomonas fluorescens) was found as the best enzyme catalyst for kinetic resolution and ruthenium supported on Al2O3as a potential heterogeneous catalyst for racemization of the starting material. By combining the two reactions, a simple dynamic kinetic resolution of rac‐2‐hydroxy‐1‐indanone producing (R)‐1‐oxo‐indan‐2‐yl butanoate was developed. Under optimal conditions, the product was obtained in 92 % eeat approximately 90 % conversion.

Fuels derived from biobased materials are attracting attention for their potential in securing the energy supply and protecting the environment. In this Minireview, we evaluate the use of biobased sources, particularly fatty acids and triglycerides from seed oils and animal fats, as fuels. The physical and chemical properties of these fatty acids and triglycerides are discussed, including the link to their sources and current availability to meet fuel demands. The current technologies, also known as the first‐generation ones, for converting triglycerides into fuels are covered, including conventional methods such as transesterification, pyrolysis, cracking, and emulsions. Recent, second‐generation technological developments that lead to more commercially viable biofuels based on diesel‐like hydrocarbons are also discussed.