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[EN] The aim of this study was to cast light on the effects of EconomasE™ (EcoE), a patented pre-mixture of nutritional additives consisting mainly of organic selenium (0.15 or 0.30 mg/kg feed; Se) combined with vitamin C (5 and 10 mg/kg feed; VC), compared to DL-α-tocopherol acetate (100 or 200 mg/kg feed; VE) dietary supplementation on rabbit performance and meat quality. In fact, the role of Se supplementation in the rabbit diet has not yet been elucidated in the literature and, more specifically, there are no studies on the possible synergistic action between organic Se compared with VE on lipids, fatty acids (FA) and the oxidative stability of two glycolytic muscles, longissimus lumborum (LL) and biceps femoris (BF). Two hundred and seventy New Zealand White rabbits were divided into five dietary groups of 54 rabbits each: 1) control (basal diet = BD; CTRL); 2) VE100 (BD + VE100 mg/kg); 3) VE200 (BD + VE200 mg/kg); 4) EcoE100 (BD + EcoE100 mg/kg); and 5) EcoE200 (BD + EcoE200 mg/kg). Neither of the antioxidant treatments affected growth performance, carcass traits or meat characteristics. Lipid and fatty acid contents were similar in LL and BF and not influenced by the dietary treatment. Meat oxidative stability was strongly improved by both antioxidants. These findings indicate that both EcoE and VE greatly improved the oxidative stability of LL and BF muscles at the dosage rates which, from an economic point of view, would normally be included in the formulation of feeds for rabbits., This study is part of a multidisciplinary research project funded by the Department of Veterinary Medical Science (University of Bologna, Italy). The authors thank Martini Group Spa (Budrio di Longiano, FC, Italy) who provided animals and feeds, and Alltech (Casalecchio di Reno, BO, Italy) who supplied the EcoE.

Reverse microemulsion-based synthesis was successfully applied to the preparation of nanosized TiO2 particles in anatase and rutile crystalline phases. The resulted nano-oxides were found to have smaller average crystalline size, higher surface area and narrower band gap than commercial TiO2 samples, P25 and DT-51. All the TiO2 materials were used as supports for platinum nanoparticles prepared by incipient wetness impregnation and deposition-precipitation methods. The photo-catalytic activities of these materials were compared in the reaction of glycerol photo-reforming in aqueous media using simulated solar light. The results showed that different crystalline phases of titania have different effects on hydrogen production and selectivity of intermediate products. Anatase was found to be more selective towards glyceraldehyde, while the presence of rutile promoted a more selective reaction towards glycolaldehyde. Rutile also exhibited a higher productivity of hydrogen compared to anatase.

The electrocatalytic conversion of 5-hydroxymethylfurfural (HMF), a biomass platform molecule, to 2,5-bis(hydroxymethyl)furan (BHMF), a polymer precursor, is a fully sustainable route that operates at room temperature and pressure, using water as source of hydrogen, and avoids high H2 pressures. In this work, we investigate the use of 3D electrocatalysts, made by Ag0 electrodeposited on Cu open-cell foams (Ag/Cu), to improve the efficiency in the electrochemical conversion of HMF to BHMF in basic media at different HMF concentrations. For comparison purposes, Ag and Cu bulk foams as well as Ag, Cu and Ag/Cu foil counterparts are investigated. For diluted 0.02 M HMF solutions, BHMF is selectively produced at high HMF conversion and FE over Ag/Cu foams. The large surface area of 3D Ag/Cu foams, compared to their 2D counterparts, does not affect selectivity, but increases the rate of conversion and in turn the productivity. However, it would appear that the increase in the surface area is not enough to increase the efficiency in the conversion of more concentrated HMF electrolytes (0.05–0.50 M). The productivity of Ag/Cu is modified with electrocatalytic cycles.

The production of 2,5-furandicarboxylic acid (FDCA) from the selective oxidation of 5-hydroxymethylfurfural (HMF) is a critical step in the production of biopolymers from biomass-derived materials. In this study, we report the catalytic performance of monometallic Au and Pd, and bimetallic AuPd nanoparticles with different Au : Pd molar ratios synthesised under continuous flow conditions using a millifluidic set-up and subsequently deposited onto titanium dioxide as the chosen support. This synthetic technique provided a better control over mean particle size and metal alloy composition, that resulted in higher FDCA yield when the catalysts were compared to similar batch-synthesised materials. A 99% FDCA yield was obtained with the millifluidic-prepared AuPd/TiO2 catalyst (Au : Pd molar composition of 75 : 25) after being calcined and reduced at 200 °C. The heat treatment caused a partial removal of the protective ligand (polyvinyl alcohol) encapsulating the nanoparticles and so induced stronger metal-support interactions. The catalyst reusability was also tested, and showed limited particle sintering after five reaction cycles.

A series of gold nanoparticles in the 4–40 nm range were prepared, immobilized on activated carbon and further tested, at low base concentration, in the catalytic oxidation of 5-hydroxymethyl furfural (HMF) to 2,5-furandicarboxylic acid (FDCA). Gold particles size variation has no influence on HMF conversion but significantly affects product selectivity and carbon balance. This behavior is ascribed to the thermodynamically favorable oxygen reduction reaction on Au(100) faces. As the gold particle size decreases the Au(100)/Au(111) exposure ratio, estimated by using the van Hardeveld-Hartog model, increases as well as the FDCA selectivity. The smaller the gold particle size the smaller the 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) to FDCA ratio pointing to the gold size dependent behavior of the oxidation of the alcohol function of the HMF molecule. Ministerio de Ciencia, Innovación y Universidades ENE2017-82451-C3-3-R

The spray-freeze-drying (SFD) approach was successfully applied for the preparation of nanostructured porous mixed oxides with high surface area. The preparation of different composite materials and the encapsulation of metal nanoparticles in inorganic matrix was easily obtained using this interesting technique. In particular, TiO2-SiO2 mixed-oxides were produced at different compositions using the colloidal heterocoagulation of very stable sols, associated with SFD. Moreover, its versatility allowed the incorporation of metal. This synthetic approach led to the preparation of porous micro-granules characterised by a high homogeneity in the phase distribution. The prepared materials were active and selective in the reduction of 5-hydroxymethyl-2-furfural (HMF) to 2,5-bishydroxymethylfuran (BHMF) and in the photodegradation of rhodamine B (RhB), used as a as a stain model. These encouraging results pave the way for the use of this method for the homogeneous embedding of different typologies of catalytic active phases (metal nanoparticles, inorganic complexes, enzyme) into any kind of support (inorganic, organic, polymeric) minimizing the possibility of phase separation on a molecular scale, as also demonstrated for drugs.

This paper reports about the gas-phase reduction of methyl levulinate to γ-valerolactone (GVL) via catalytic transfer hydrogenation using ethanol as the H-donor. In particular, high-surface-area, tetragonal zirconia has proven to be a suitable catalyst for the reaction. Under optimized conditions, the reaction is selective toward the formation of GVL (yield 70%). However, both the deposition of heavy oligomeric compounds over the catalytic surface and the progressive conversion from Lewis to Bronsted acidity, due to the reaction with the water formed in situ, led to a progressive change in the chemo-selectivity, promoting side reactions, e.g. the alcoholysis of angelica lactones to ethyl levulinate. However, the in situ regeneration of the catalyst performed by feeding air at 400 °C for 2 h permitted an almost total recovery of the initial catalytic behavior, proving that the deactivation is reversible. The reaction has been tested also using a true bioethanol, derived from agricultural waste.

DRIFT characterization and DFT calculation were carried out to clarify the previously unexplored use of methanol as a H-transfer agent for the liquid-phase Meerwein-Ponndorf-Verley reduction of biomass-derived furfural using alkaline earth oxide catalysts (MgO, CaO, SrO). Methanol adsorption mechanism has been studied in detail and the energy correlated to the process has been theoretically calculated for each of the prepared catalyst to investigate the relative performances of the three basic oxides. Although, the higher-surface-area MgO displayed an exceptionally high activity for the H-transfer process at low temperatures, CaO and SrO were found to be the catalysts with the highest specific productivity per unit surface area and unit basic site. The different specific productivities of the three catalysts was explained by DRIFT with different adsorption mode selectivities (3 different modes for MgO versus only 1 for CaO and SrO, with the production of only the active methoxide), which may indicate a different methanol activation with regard to the H-transfer toward the carbonyl moiety of FAL. Furthermore, higher SrO than CaO productivity can be explained by the different basicity, which in turn leads to differences in the main methanol activation pathways. DFT calculations make it possible to gain further insight into the role of the basic strength on methanol activation and H-transfer reaction suggesting the increased ability of activating the alcohol via formation of the methoxide ion being the key factor in modulating the catalyst activity rather than the polarization of the aldehydic carbonyl group due to the coordination onto the M3C site.

The electrochemical transformation of biomass-derived compounds (e.g., aldehyde electroreduction to alcohols) is gaining increasing interest due to the sustainability of this process that can be exploited to produce value-added products from biowastes and renewable electricity. In this framework, the electrochemical conversion of 5-hydroxymethylfurfural (HMF) to 2,5-bis(hydroxymethyl)furan (BHMF) is studied. Nanostructured Ag deposited on Cu is an active and selective electrocatalyst for the formation of BHMF in basic media. However, this catalyst deserves further research to elucidate the role of the morphology and size of the coated particles in its performance as well as the actual catalyst surface composition and its stability. Herein, Ag is coated on Cu open-cell foams by electrodeposition and galvanic displacement to generate different catalyst morphologies, deepening on the particle growth mechanism, and the samples are compared with bare Ag and Cu foams. The chemical–physical and electrochemical properties of the as-prepared and spent catalysts are correlated to the electroactivity in the HMF conversion and its selectivity toward the formation of BHMF during electroreduction. AgCu bimetallic nanoparticles or dendrites are formed on electrodeposited and displaced catalysts, respectively, whose surface is Cu-enriched along with electrochemical tests. Both types of bimetallic AgCu particles evidence a superior electroactive surface area as well as an enhanced charge and mass transfer in comparison with the bare Ag and Cu foams. These features together with a synergistic role between Ag and Cu superficial active sites could be related to the twofold enhanced selectivity of the Ag/Cu catalysts for the selective conversion of HMF to BHMF, that is, >80% selectivity and ∼ 100% conversion, and BHMF productivity values (0.206 and 0.280 mmol cm–2 h–1) ca. 1.5–3 times higher than those previously reported.

Copper and nickel mixed catalysts obtained by calcination of iron and aluminium hydrotalcites (layered double hydroxides, LDH) have been tested in the conversion of a lignin model dimer in subcritical methanol. Phase distribution and textural properties of the catalysts were characterized by X-ray diffraction Rietveld analysis and N2 physisorption. The presence of copper was critical for effective hydrogenation, both by direct hydrogen transfer from methanol to aldehyde groups and by reactivity of products from methanol reforming. TPR experiments showed that the hydrogenation activity was promoted by an enhanced reducibility of the Cu-catalysts, related to the presence of other oxide components. Characterisation of the catalysts after reaction indicated that metallic copper was formed by the reduction of CuO by methanol and that modifications of the oxide catalysts in the reaction medium played a major role in the formation of active sites.

The deposition of precisely controlled clusters from the beam onto suitable supports represents a novel method to prepare advanced cluster-based catalysts. In principle, cluster size, composition, and morphology can be tuned or selected prior to deposition. The newly invented matrix assembly cluster source (MACS) offers one solution to the long-standing problem of low cluster deposition rate. Demonstrations of the cluster activities under realistic reaction conditions are now needed. We deposited elemental silver (Ag) and gold (Au) clusters onto gram-scale powders of commercial titanium dioxide (TiO2) to investigate the catalytic oxidation of nitrophenol (a representative pollutant in water) by ozone in aqueous solution, as relevant to the removal of waste drugs from the water supply. A range of techniques, including scanning transmission electron microscopy (STEM), Brunauer-Emmett-Teller (BET) surface area test, and X-ray photoelectron spectroscopy (XPS), were employed to reveal the catalyst size, morphology, surface area, and oxidation state. Both the Ag and Au cluster catalysts proved active for the nitrophenol ozonation. The cluster catalysts showed activities at least comparable to those of catalysts made by traditional chemical methods in the literature, demonstrating the potential applications of the cluster beam deposition method for practical heterogeneous catalysis in solution.

A series of gold catalysts supported on pure CeO2, ZrO2, and two different Ce-Zr mixed oxides have been prepared and tested in the 5-hydroxymethyl-2-furfural oxidation reaction. All catalysts show high catalytic activity (100% conversion) and important selectivity (27–41%) to the desired product i.e., 2,5-furandicarboxylic acid at low base concentration. Products selectivity changes with the support nature as expected, however, the observed trend cannot be related neither to gold particle size, nor to catalyst reducibility and oxygen mobility. An important relation between the FDCA selectivity and the support textural properties is observed, conducing to the general requirement for optimal pore size for this reaction. Ministerio de Economía y Competitividad ENE2017-82451-C3-3-R

Polar lipids (PoL) represent a new promising dietary approach in the prevention and treatment of many human diseases, due to their potential nutritional value and unique biophysical properties. This study investigates the effects of catching season and oven baking on the fatty acid profiles (FAP) of PoL in four species of blue-back fish widely present in the North Adriatic Sea: anchovy (Engraulis encrasicholus), sardine (Sardina pilchardus), sprat (Sprattus sprattus), and horse mackerel (Trachurus trachurus). PoL levels (427-652 mg/100 g flesh) varied among the four species, with no significant seasonal variations within species. FAP of raw fillets were particularly high in polyunsaturated fatty acid (PUFA), especially docosahexaenoic acid (DHA) and EPA; total PUFA was constant in all species throughout the year, while long-chain n-3 polyunsaturated fatty acid (n-3 PUFA) rose in spring (except in sprat), especially due to the contribution of DHA. The FAP response for PoL to oven baking was species-specific and, among n-3 PUFA, DHA exhibited the greatest heat resistance; the influence of oven baking on FAP was found to be correlated with the catching season, especially for anchovy and sardine, while sprat PoL were not affected by cooking processes. The four species analyzed in this study presented very low n-6/n-3 fatty acid ratios and highly favorable nutritional indices, emphasizing their PoL qualities and promoting their role in increasing human n-3 PUFA intake. The four species can be considered as superior sources of n-3 PUFA and can be employed as supplements in functional food manufacturing and in pharmaceutical and cosmetic industries.

The hydrodeoxygenation of furfural (FU) was investigated over Fe-containing MgO catalysts, on a continuous gas flow reactor, using methanol as a hydrogen donor. Catalysts were prepared either by coprecipitation or impregnation methods, with different Fe/Mg atomic ratios. The main product was 2-methylfuran (MFU), an important highly added value chemical, up to 92% selectivity. The catalyst design helped our understanding of the impact of acid/base properties and the nature of iron species in terms of catalytic performance. In particular, the addition of iron on the surface of the basic oxide led to (i) the increase of Lewis acid sites, (ii) the increase of the dehydrogenation capacity of the presented catalytic system, and (iii) to the significant enhancement of the FU conversion to MFU. FTIR studies, using methanol as the chosen probe molecule, indicated that, at the low temperature regime, the process follows the typical hydrogen transfer reduction, but at the high temperature regime, methanol dehydrogenation and methanol disproportionation were both presented, whereas iron oxide promoted methanol transfer. FTIR studies were performed using furfural and furfuryl alcohol as probe molecules. These studies indicated that furfuryl alcohol activation is the rate-determining step for methyl furan formation. Our experimental results clearly demonstrate that the nature of iron oxide is critical in the efficient hydrodeoxygenation of furfural to methyl furan and provides insights toward the rational design of catalysts toward C&ndash, O bonds&rsquo, hydrodeoxygenation in the production of fuel components.

In the field of biomass valorization, reductive processes for the sustainable production of bio-fuel additives and chemicals have gained a great deal of interest. Catalytic transfer hydrogenation, which uses alcohols as the hydrogen source, offers an interesting approach that avoids the use of both high H2 pressure and precious metal catalysts. This H-transfer reaction has been studied in many processes using different type of catalysts (acid, base, and metal-supported materials); recently, reductive upgrading of biomass for chemicals and fuels production through catalytic hydrogen transfer processes, has gained increasing attention. Among the other biomass derived molecules, the H-transfer process can be applied to reduce furfural (FU) and 5-hydroxymethylfurfural (HMF). Reported data demonstrated that in the presence of secondary alcohols and metal-based catalyst, remarkable results were obtained in these reactions, leading to the selective production of furfuryl alcohol (FAL) and 2,5-bis(hydroxymethyl)furan (BHMF). Recent examples demonstrated the possibility to reduce FU and HMF both in liquid and gas phase using inexpensive oxides such as MgO, CaO, SrO, Mg/Fe/O and FeVO4, and methanol as hydrogen donor. Compared to the alcohols typically used for carbonyl reductions, methanol showed the advantage of producing gaseous components as the only co-products, which are easily separated from the reaction medium. Moreover, the in situ generation of formaldehyde, due to methanol dehydrogenation, can contribute to the formation of different products. Indeed, in the studied processes, furfuryl alcohol (FAL), bis-hydroxymethylfuran (BHMF) and methyl furan (MF) were produced with high selectivity depending on the reaction conditions and on the chosen catalyst. The obtained results highlight the potential application of the H-transfer reaction over solid basic oxides as an efficient process for the selective de-oxygenation of biomass derived molecules.

Au-Based catalysts supported on nanosized NiO (nNiO) were synthesized and were investigated in the oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) under base-free conditions using molecular oxygen as the oxidant, at 90 °C. By choosing the optimal composition of Au–Pd nanoparticles (6 : 4 Au/Pd atomic ratio), we report an efficient and stable nNiO-supported Au–Pd alloy catalyst. The presence of nNiO and Au–Pd nanoparticles on the surface was essential to achieve high conversion (95%) and high activity, high yield of FDCA (70%) and good level of stability. Significant synergistic effects were observed between Au and Pd in the alloy as well as on NiO. The present work provides mechanistic insights into the alloying effect and support-metal interaction in terms of understanding better the role of the alloy and support in affecting specific reaction pathways. Finally, the outcome of this knowledge can help develop efficient catalysts for the aerobic oxidation of biomass-derived molecules under base-free conditions in water and under mild reaction conditions.

The catalytic activity of a simple Au/Al2O3 catalytic system prepared by the direct anionic exchange (DAE) method was evaluated in the selective 5-hydroxymethylfurfural (HMF) oxidation under mild conditions, using molecular oxygen as the oxidant. The influence of the HMF/NaOH ratio and reaction time on product yield and distribution were studied and discussed in detail. Extremely high activity and selectivity were observed in mild conditions, with 99% of 2,5-furandicarboxylic acid (FDCA) production at full HMF conversion after 4 h with the use of only 4 equivalents of NaOH at 70 °C. Catalyst viability and stability were verified by repeating the cycle up to five times. Changes in the nature of the support were also contemplated by introducing some ceria fraction, i.e. 20 wt%.

Due to their chemical versatility and harmless nature, organic carbonates (OCs) have been indicated as proper raw materials for the replacement of noxious and waste-producing reactants. In particular, from the development of chlorine-free processes for the synthesis of OCs, the design of industrial processes based on the conversion of the latter has become a crucial topic for both academia and industry. The industrialization of chemical processes that involve the use of CO2 as starting material for the synthesis of OC finally made OCs the sustainable counterpart of halogenated compounds in alkylation and carboxylation reactions. In this chapter, insights on the evolution and current development of organic carbonates synthesis and their industrial application will be given, pointing out the industrial processes in which organic carbonates chemistry provided a viable, sustainable alternative to traditional approaches.

Lignocellulosic biomass offers a unique resource for the sustainable production of bio-derived chemicals and fuels in replacement of the fossil products. Lignin, a major component of biomass is largely underexploited, mainly due to its recalcitrant molecular structure which hinders the development of depolymerization techniques. Considering its rich phenolic functionalities in lignin, catalytic transformations can render lignin a viable source of value-added chemicals. The present contribution aims to highlight the emerging heterogeneous depolymerization strategies, challenges and economic viability aspects of pyrolysis, reduction and oxidation processes.

The objective of this Special Issue is to provide new diverse contributions that can demonstrate recent applications in biomass transformation using heterogeneous catalysts. In recent decades, a wide variety of biomass-derived chemicals have emerged as key platform chemicals for the production of fine chemicals and liquid fuels using heterogeneous catalysts as the preferred option for most of the developed and proposed catalytic processes. A range of heterogeneous catalysts have been evaluated for effective biomass conversion, such as supported metal nanoparticles, mixed metal oxides and zeolites, where the control of particle size, porosity, acid-basic and redox properties is crucial for providing active, stable and selective heterogeneous catalysts. Moreover, the crucial role of the solvent, choice of reactor design and final chemical processes for controlling activity, selectivity and deactivation phenomena has been demonstrated

LaAlO3 perovskites, as such and with 25% molar Al substitution by Cu, Co, or Ga, have been prepared by sol-gel methods and tested as heterogeneous catalysts in the gas-phase conversion of ethanol. LaAlO3 presented a significant acidic character, with high formation of ethylene by ethanol dehydration. B-site substitutions increased the basicity of the catalysts, favoring the dehydrogenation of ethanol to acetaldehyde. The most reducible Cu- and Co-substituted materials, characterized by easier formation of surface oxygen vacancies, promoted the self-condensation of acetaldehyde by the Tishchenko mechanism, with formation of acetone and odd-carbon number products. Aldol coupling of acetaldehyde, favored on pure and Ga-substituted LaAlO3, led to the formation of butadiene and hexadiene. The role of Ga insertion, favoring both dehydrogenation of ethylene and dehydration of higher alcohols, corresponds to an amphoteric character. The formation of olefins and diolefins on all catalysts suggests that LaAl-based materials present the most acidic character among La-perovskites.

The three Ni-based metal-organic frameworks (MOFs) Ni(BDP), Ni(BPEB) and Ni3(BTP)2 [H2BDP = 1,4-(4-bispyrazolyl)benzene; H3BTP = 1,3,5-tris(1H-pyrazol-4-yl)benzene], possessing square planar, potentially accessible metal sites, were preliminarily tested as catalystsin the base-free selective oxidation of hydroxymethylfurfuralmto 2,5-diformylfuran (DFF). While Ni(BDP) undergoes degradation, Ni3(BTP)2 is the most active of the three MOFs, yielding 27% DFF after 24 h with a selectivity close to 100% under relatively mild reaction conditions (120 °C, 30 bar, water as solvent). Upon flowing a model probe, in situ DRIFT and FT-IR spectroscopy were employed to rationalize the different performances of Ni(BPED) and Ni3(BTP)2 in terms of adsorbate-adsorbent interactions. Not only hydrogen bonds are at work between the hydroxyl functionalityof the probe and the pore walls of the MOF, but also and more importantly, banfs ascribed to Ni-OR stretching are detected, denouncing the insurgence of Ni-probe interactions, The different intensity of these bands in the two cases confirms the different accessibility of the metal centers, as suggested by Crystal structure analysis and catalytic tests.

The possibility of producing on-board H2 by dehydrogenation of petrol derivates is interesting for transport applications. Traditional Pt-Sn systems, however, cannot be used without purifying the fuel from its sulphur content, and the dehydrogenation reaction consumes energy owing to its endothermic nature. To limit the energy demand for the entire process, it is necessary to eliminate the need for any reactant purification step, thus feeding the real fuel without desulphurization. In this respect, Ni- and Co-based catalysts capable of working under hydrodesulphurization conditions answered such demand, allowing them to carry out the reaction in the presence of sulphurated organic substrates. Tests conducted on nickel and cobalt phosphides, as prepared from the corresponding dihydrogenphosphite by temperature programmed reduction and supported on silica Cab-osil, indicated these materials as very active catalysts capable of producing 1500 N l per h per kgCAT of H2 after 24 h of reaction in the presence of 50 ppm of sulfur. These catalysts remained active and stable even when 250-500 ppm of sulphur was introduced in the feed.

A new synthetic route for obtaining α-6-hydroxy-6-methyl-4-enyl-2H-pyran-3-one, a useful synthon for the preparation of biologically active compounds, has been developed from the bio-based platform derivative (2,5-bis-hydroxymethylfuran) BHMF. The reaction occurs with good selectivity in water, under mild conditions and employing an heterogeneous recyclable acid (Amberlyst 15®) as catalyst, avoiding the use of oxidizing agents. The reaction provides access to poly-oxygenated compounds characterized by a molecular motif commonly found in many natural products.

The hydrogenation of biomass-derived molecules is a key reaction in upgrading these compounds into chemicals and fuels. The use of catalytic transfer hydrogenation, employing alcohols as hydrogen sources, offers an alternative approach to this process, avoiding the use of H2 under high pressure and precious metal catalysts. In this work, the gas-phase conversion of biomass-derived furfural into furfuryl alcohol and 2-methylfuran was studied, using methanol as the H-transfer agent and MgO-based catalysts. Pure MgO was shown to reduce furfural into its corresponding unsaturated alcohol at low reaction temperatures (lower than 350 °C), thus allowing selective H-transfer from methanol to the substrate. 2-Methylfuran formation, associated with the partial rearrangement of furan rings to cyclopentanones, was observed at high temperatures. Conversely, the distribution of compounds obtained with Mg/Fe/O was significantly different, with 2-methylfuran formation prevailing when the reaction was carried out between 300 and 400 °C. In this temperature range, upon tuning the reaction conditions, a very high yield of 2-methylfuran was produced, thus indicating that the mixed oxide allows efficient sequential transfer hydrogenation/hydrogenolysis reactions. These results highlight the potential application of the H-transfer reaction over MgO-based catalysts as an efficient process for the selective de-oxygenation of biomass-derived molecules.

Over the past decade, a great deal of effort has been devoted to developing reductive processes in the field of biomass valorisation for the sustainable production of bio-fuel additives and chemicals. Catalytic transfer hydrogenation, which uses alcohol as the hydrogen source, is an interesting approach that avoids the use of both high H2 pressure and precious metal catalysts. In this work, the vapour-phase production of 2-methylfuran from biomass-derived furfural (FU), using methanol as the H-transfer agent and FeVO4 catalyst, was studied. At a temperature of 320 °C it was possible to achieve 80% yield of 2-methylfuran, with small amounts of 2,5-dimethylfuran and 2-vinylfuran as by-products. Catalyst characterization highlighted that FeVO4 reduction took place under the studied conditions, leading to the in situ development of a true active phase. The study of the reaction network permitted us to infer on the relative contribution of H-transfer and hydrogenation, the latter from the in situ generated formaldehyde and H2, to 2-methylfuran, formation. The reported results indicate the potential application of H-transfer with FeVO4 catalysts as an efficient process for the selective de-oxygenation of biomass-derived molecules.

In this work, an eco-friendly process for piperonal synthesis from piperonyl alcohol oxidation was developed. Piperonal was obtained with 100% selectivity under solvent free conditions, using air as oxidant at atmospheric pressure. The preparation of high surface area CeO2 using a surfactant-template method allowed the preparation of a catalyst with highly dispersed Au nanoparticles having an average diameter of about 1 nm. The obtained results, using Au/CeO2 catalysts, suggested that the reaction network consists in the rapid oxidation of piperonyl alcohol to piperonal. Increasing reaction time to promote alcohol conversion a very small amount of formed aldehyde undergoes to further oxidation to the acid. Subsequently, piperonylic acid can easily react with the alcohol, leading to the formation of the ester that can be adsorbed on the catalyst surface, deactivating the materials. Nevertheless, the fine-tuning of the process, using solvent free conditions, air and low reaction time, demonstrated the possibility to control catalyst deactivation. Indeed, gold supported on nano-CeO2 were able to catalyse the production of piperonal without by-product formation, with 35% of piperonyl alcohol conversion after 45 min of reaction and the catalyst can be recycled without any activity loss, demonstrating the possibility of scaling up a low conversion continuous process or low reaction time batch process. No toxic reagents were used neither for catalysts preparation nor for catalytic tests and the use of air as oxidant improved the safety of the process. The latter, together with the absence of a solvent, can led to important advancements in the industrial applications reducing the costs of the purification section. This versatile approach, interesting from both the economic and the environmental point of view, was also applied in the synthesis of other aromatic aldehydes, such as benzaldehyde, vanillin and anysil aldehyde, highlighting the importance of this process.

In the present work, Pt and Pt/Sn nanoparticles (NPs), synthesized from carbonyl cluster precursors were deposited on TiO2 and the resulting materials were tested as catalysts in selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA). The work was mainly focused on the study of the formation of bimetallic or mixed oxide-metal nanoparticles on TiO2 starting with Pt/Sn carbonyl clusters and on the structure-activity relationship in the reaction of HMF oxidation in base-free conditions. The developed synthesis procedure allowed to obtain very small mono and bimetallic particles characterized by a narrow particle size distribution. Promising results in base-free FDCA production have been achieved using the prepared samples. In particular, the introduction of Sn in an equimolar amount with Pt improved the catalyst activity as well as its time stability upon operation, demonstrating that the modification of Pt electronic configuration by Sn is a key factor for the mastering of functional performances.

The production of second-generation fuels from biomass is entering a new stage focused on large projects and industrial initiatives. However, the uncertain scenario in terms of climate change commitment and burden share, fossil fuel price, and renewable legislation limits does not provide the best environment for a large-scale spread of new technologies; furthermore, this innovation still requires a real breakthrough in order to lead to a clearly enhanced efficiency and sustainability. There are different approaches driving the conversion of biomass bulk or its fraction into fuel: (i) the fermentation process to bioethanol and biomethane, (ii) the production of oxygenated liquid compounds by several treatment (pyrolysis, liquefaction, triglyceride extraction, etc.) followed by hydrotreating (HDT) to upgrade the bio-oil produced, and (iii) gasification or aqueous phase reforming (APR), which produces syngas and hydrocarbons or alcohols. Gasification uses an oxidizing agent (air, steam, oxygen, or a combination of these) for the high-temperature transformation of a carbonaceous feedstock into a gaseous energy carrier consisting of permanent, non condensable gases, mainly syngas. Subsequently, in a separate stage, the syngas obtained is transformed by Fischer–Tropsch (FT) reaction into diesel or other syngas fuel such as methanol dimethyl ether (DME) or C2+ alcohols. The APR reaction is an alternative pathway to gasification for the transformation of biomass and its main components (sugars, polyols, and even proteins) into several products such as hydrogen, hydrocarbon, and oxygenated molecules, with the main products depending on the reaction conditions, process configuration, and catalysts.The APR treatment is applied to a hydrolyzed biomass in water solutions at 225–300 ∘C in subcritical conditions.

For the conversion of raw materials into fine chemicals and high-value building blocks, reliable oxidation methods have been found to be indispensable tools in modern organic synthesis. Various methods with remarkable efficiencies have been developed for a wide array of oxidative transformations which are now well established. However, since most of these standard protocols rely on the use of hazardous terminal oxidants or cause the generation of significant amounts of waste products, there is still an evident need for methodological improvements with respect to environmental and economic issues. Especially in terms of waste product minimization and the use of renewable materials, catalytic aerobic transformations offer some ideal features of a ‘green’ process towards sustainability. In particular, the oxidation of alcohols is one of the most important synthetic operations in both the organic chemistry laboratory and the chemical industry. Although classic oxidation reactions can be very efficient and selective, they often involve the use of stoichiometric reagents and halogenated solvents, resulting in the generation of large quantities of wastes. The urgent need for more sustainable chemical processes hasprompted the development of mild and selective oxidation methods based on the use of green reagents and solvents. In this context, the direct use of oxygen as an oxidizing reagent is a very desirable feature for modern synthetic methods. Hence new catalysts for the aerobic oxidation of alcohols have attracted much attention in recent years. Transition metal-based systems have been successfully used for the aerobic oxidation of alcohols to the corresponding carbonyl compounds with excellent performances of several transition metal catalysts. Homogeneous, heterogeneous and nanocatalysis are the subject of intense research in this field and, rather than aspiring to be exhaustive, this chapter deals with the comparison of those macro-areas within the context of efficiency in reaction design, by following the principles of green and sustainable chemistry for oxidation processes.