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Along the development of ionic porous organic polymers, simple and efficient synthetic methods are actively pursued. Herein, the Debus–Radziszewski reaction is applied to synthesize ionic conjugated microporous polymers (iCMPs) in one step. A series of imidazolium-linked iCMP-X (X = 1, 2, 3) are developed for CO2 sorption and in situ conversion with epoxide into cyclic carbonates. The as-synthesized iCMPs are characterized in detail by scanning electron microscope, solid-state nuclear magnetic resonance, X-ray photoelectron spectroscopy, X-ray diffraction analysis, N2/CO2 sorption, and more. Among all synthesized iCMPs, iCMP-1 possesses the highest specific surface area and in turn the strongest CO2 sorption capacity. Moreover, through a simple anion ion exchange reaction with halide, iCMP-1 is transformed to iCMP-1@Cl that embodies significant catalytic capability for converting CO2 into cyclic carbonates.

The present review revisits representative studies addressing the development of efficient Pd-based carbon-supported heterogeneous catalysts for two important reactions, namely, the production of hydrogen from formic acid and the hydrogenation of carbon dioxide into formic acid. The HCOOH-CO2 system is considered a promising couple for a hydrogen storage system involving an ideal carbon-neutral cycle. Significant advancements have been achieved in the catalysts designed to catalyze the dehydrogenation of formic acid under mild reaction conditions, while much effort is still needed to catalyze the challenging CO2 hydrogenation reaction. The design of Pd-based carbon-supported heterogeneous catalysts for these reactions encompasses both the modulation of the properties of the active phase (particle size, composition, and electronic properties) and the modification of the supports by means of the incorporation of nitrogen functional groups. These approaches are herein summarized to provide a compilation of the strategies followed in recent studies and to set the basis for a hydrogen storage system attained using the HCOOH-CO2 couple.

Molecular solar thermal energy storage (MOST) systems are rapidly becoming a feasible alternative to energy storage and net-zero carbon emission heating. MOST systems involve a single photoisomerization pair that incorporates light absorption, storage, and heat release processes in one recurring cycle. Despite significant recent advancements in the field, the catalytic back-reaction from MOST systems remains relatively unexplored. A wide range of applications is possible, contingent on the energy densities of the specific photoisomers. Here, we report platinum-, copper-, and nickel-based heterogeneous catalysts screened in batch conditions for the back-conversion reaction on the cyano-3-(4-methoxyphenyl)-norbornadiene/quadricyclane pair. Catalyst reactivities are investigated using structural characterization, imaging techniques, and spectroscopic analysis. Finally, the thermal stability is also explored for our best-performing catalysts.

The present work aimed to evaluate the effectiveness of Ca(OH)2 obtained from eggshells as a catalyst in the transesterification of first-generation oil compared to catalysts such as Na(OH) and Ca(OH)2.GR. The eggshells were subjected to thermal treatment in a muffle furnace with temperature intervals to reduce CaCO3 to CaO. Once the calcium oxide was obtained, it was mixed with distilled water, which evaporated over time due to the exothermic reaction of CaO conversion to produce Ca(OH)2. The results showed that Ca(OH)2.GR has greater efficacy than Ca(OH)2 obtained from eggshells, while Na(OH) proved superior to the other catalysts used in the study, El presente trabajo tuvo como objetivo obtener hidróxido de calcio a partir de las cáscaras de huevo y utilizarlo como catalizador en la transesterificación de aceite de primera generación y evaluar este compuesto con otros catalizadores como hidróxido de sodio e hidróxido de calcio de grado reactivo. Se realizó un proceso de selección y tratamiento de las cáscaras de huevo. Los principales resultados muestran que el hidróxido de calcio de grado reactivo tiene mayor eficacia que el hidróxido obtenido a partir de las cáscaras de huevo, mientras que el hidróxido de sodio demostró ser muy superior en comparación a los demás catalizadores evaluados en el estudio.

Anion-exchange-membrane electrolysis is positioned to play a key role in the predicted exponential growth of green hydrogen technology with essential R&D advances. We reveal key design parameters essential to commercialization. First, stable alkaline oxygen-evolution reaction catalysts with high electronic conductivity and minimal surface reconstruction during operation must be designed. Alkaline catalyst layers must also be applied to the membrane electrode assembly with scalable, industrially relevant techniques. Second, ionomer oxidation mitigation strategies must be developed. This approach could also target other creative catalyst layer design, such as phase-separation control to protect oxidation-prone organic components or catalyst engineering to direct selectivity for hydroxide over polymer oxidation. If competitive efficiency and durability can be achieved in pure water, AEM electrolysis has the potential to become a dominant electrolyzer technology.

Styrene-divinylbenzene copolymers (STY-DVB) have a wide range of applications as ion exchange resins and adsorbents. The synthesis of these copolymers has been the subject of studies for a long time due to the diverse variables that can be adjusted or modified, such as porogen, size, agitation time, agitation speed, and sulfonating agent, among others; with the purpose of obtaining polymeric support with adequate physicochemical characteristics such as inertness, thermal stability, capacity to be reusable, and low toxicity. In this work, we propose the variation of parameters of synthesis in the suspension of these resins, such as the amount of porogen to be used, the agitation speed, and the amount of crosslinking agent divinyl benzene (DVB), and determine its influence on the exchange capacity. It was possible to obtain three resins with particle size between 55-75 µm (Resin 1) and 90-200 µm (Resins 2 and 3), with exchange capacities between 3-4.38 mEq/g, values that correspond to acid macroporous resins that will allow their subsequent use as heterogeneous catalysts and solid acids., Resumen Los copolímeros de estireno-divinilbenceno (EST-DVB) tienen un amplio rango de aplicaciones como resinas de intercambio iónico y absorbentes. La síntesis de estos copolímeros ha sido objeto de estudios durante mucho tiempo debido a las diversas variables que se pueden ajustar o modificar, como, por ejemplo, porógeno, tamaño, tiempo de agitación, velocidad de agitación, agente sulfonante, entre otros, con la finalidad de obtener un soporte polimérico con características físico-químicas adecuadas, tales como, inercia, estabilidad térmica, y la capacidad de ser reutilizables y de baja toxicidad. En este trabajo se plantea la variación de parámetros de síntesis en suspensión de estas resinas, como la cantidad de porógeno a utilizar, la velocidad de agitación y la cantidad de agente entrecruzante divinilbenceno (DVB), para determinar su influencia en la capacidad de intercambio. Se pudo obtener tres resinas con tamaño de partículas entre 55-75 µm (Resina 1) y 90-200 µm (Resinas 2 y 3), y con capacidades de intercambio entre 3-4,38 mEq/g, valores que corresponden a resinas macroporosas ácidas, lo que permitirá su uso posterior como catalizadores heterogéneos y ácidos sólidos.

The hydrogenation of 1,3 Butadiene (BD) is an important industrial process that is generally used to generate butene, which is a key feedstock to produce a variety of chemicals such as polymers, plastic, and synthetic rubber. This process involves reacting BD with hydrogen using different metallic Ni-based catalysts. In this study, Ni/Al2O3 and Ni/Nb2O5 catalysts were used and investigated to perform the hydrogenation reaction because of their commercial availability, effective hydrogenation activity, and affordability compared to Platinum Group Metal (PGM) catalysts. The catalytic reactions were conducted using a quartz tube reactor between a temperature range of 50 and 400°C at regular intervals of 50°C under operating pressures of 1 atm. A comprehensive analysis of the products from the reaction was done using Gas-Chromatography with Mass Spectrometry (GC-MS) detector, where we noticed both mono-substituted aromatics, and gases products such as butenes. We noticed that a 100% conversion of BD occurred at 200°C and collaborated our GC-MS results with infrared spectroscopy in order to develop a reaction mechanism and confirm the presence of certain products. In this way, we show the low-temperature conversion of BD represents an economically efficient method to add value to less-useful, more-reactive hydrocarbons with conjugative double bonds into high-value petrochemicals such as Benzene, Toluene and Xylene (BTX). The oxidation of butadiene is an efficient method of converting unsaturated hydrocarbons with a high degree of toxicity like butadiene to less harmful products such as CO2. For this purpose, we investigate the use of Ni and Cu based catalysts such as 5% Ni/Al2O3, 5% Ni/Nb2O5 and 5-10% Cu-CeO2/Nb2O5 to analyze the different products possible, their chemical nature, selectivity/relative yields, and through GC-MS, Gas Chromatography-Thermal Condu

[Abstract] Two new monobasic tridentate O⁀N⁀N donor ligands, HL1 (I) and HL2 (II) have been obtained in two steps by reacting phenylhydrazine and salicylaldehyde or 3,5-di-tert-butylsalicylaldehyde and then reacting the resulting compounds with 2-chloromethylbenzimidazole in the presence of triethylamine. The reaction of [VIVO(acac)2] with these ligands in a 1:1 molar ratio in dry methanol led to the formation of homogeneous oxidovanadium(IV) complexes [VIVO(acac)L1] (1) and [VIVO(acac)L2] (2). Immobilization of these complexes on chloromethylated polystyrene (PS-Cl) cross-linked with divinyl benzene resulted in corresponding polymer-supported heterogeneous complexes PS-[VIVO(acac)L1] (3) and PS-[VIVO(acac)L2] (4). Ligands (I and II), homogeneous complexes (1 and 2) and heterogeneous complexes (3 and 4) have been characterized using elemental analysis and various spectroscopic techniques. A single crystal X-ray diffraction study of I and 1 further confirms their structures. The oxidation state IV of vanadium in these complexes was assured by recording their EPR spectra while heterogeneous complexes were further characterized using field emission-scanning electron microscopy (FE-SEM) combined with energy dispersive X-ray analysis (EDS) and atomic force microscopy (AFM). All vanadium complexes have been explored for their catalytic potential to one-pot-three-component reactions (reagents: benzil, ammonium acetate and various aromatic aldehydes) for the efficient synthesis of 2,4,5-triphenyl-1H-imidazole derivatives (nine examples). Various reaction conditions have been optimized to obtain a maximum yield (up to 96%) of catalytic products. It has been found that heterogeneous complexes show excellent catalytic activity and are recyclable up to five catalytic cycles.

Colloidal syntheses of nanomaterials offer multiple benefits to study, understand, and optimize unsupported and supported catalysts. In particular, colloidal syntheses are relevant to the synthesis of (precious) metal nanoparticles. By separating the synthesis of the active phase, i.e., the nanoparticles, from supporting steps, a deeper knowledge and rational control of the properties of supported catalysts is gained. The effect(s) of the size, shape, and composition of the nanoparticle, the nature of the support, or the metal loading on a support can be studied in more systematic ways. The fundamental knowledge gained paves the way for catalyst optimization by tuning the catalyst activity, selectivity, and stability. However, most colloidal syntheses require the use of additives or surfactants, which are detrimental to most catalytic reactions because they typically block catalyst active sites. Surfactant removal is therefore often required, which adds complexity to the synthesis and the analysis of the obtained results. Developing surfactant-free strategies to obtain stable colloidal nanoparticles is therefore a rising field of research that is here reviewed. A focus is given to laser synthesis and processing of colloids-, solution plasma process-, N,N-dimethylformamide-, polyol-, and recently reported monoalcohol-based syntheses. The relevance of these synthetic approaches for catalysis is detailed with a focus on heterogeneous catalysis and electrocatalysis.

Catalytic gas-phase hydrogenation of CO2 into CH4 was tested under three different nickel/aluminate catalysts obtained from precursors of hexaaluminate composition (MAl16O19, M = Mg, Ca, Ba). These catalysts were prepared using a carbon template method, where carbon is self-generated from a sol-gel that contains an excess of citric acid and the Al and M salts (Ba2+, Ca2+, Mg2+) by two-step calcination in an inert/oxidizing atmosphere. This procedure yielded Ni particles decorating the surface of a porous high surface area matrix, which presents a typical XRD pattern of aluminate structure. Ni particles are obtained with a homogeneous distribution over the surface and an average diameter of ca 25–30 nm. Obtained materials exhibit a high conversion of CO2 below 500 °C, yielding CH4 as a final product with selectivity >95%. The observed trend with the alkaline earth cation follows the order NiBaAlO-PRx > NiCaAlO-PRx > NiMgAlO-PRx. We propose that the high performance of the NiBaAlO sample is derived from both an appropriate distribution of Ni particle size and the presence of BaCO3, acting as a CO2 buffer in the process.

Methanol carbonylation was evaluated over heterogeneous catalysts based on Cu-exchanged zeolitic materials with different topology: Cu@MOR, Cu@FER, and Cu@ZSM-5. Despite the similar Si/Al ratios, it is crucial to acknowledge that the acid strength is influenced by the framework topology, as supported by the NH3-TPD results. This, along with other characterization techniques allowed us to estimate the impact of pore size and pore distribution in these microporous materials on catalytic performance. The channel structure influenced catalytic parameters such as conversion and selectivity. The higher methanol conversion achieved on Cu@FER shows the importance of Brønsted acid sites and redox centres location regarding the topology of the material. Concerning the selectivity, the production of acetic acid was endorsed by the 12-MR (MOR) channels, methyl acetate's production by the 10-MR (FER) channels. Finally, the presence of 6-MR (ZSM-5) channels led to a complete selectivity towards DME production. The reaction mechanism was elucidated via operando DRIFTS-MS and results revealed a bifunctional mechanism in which methanol adsorbs and dehydrates on acidic Brønsted sites and CO is activated over Cu+ species.

In this study, a simple and scalable method to obtain heterogeneous indium nanoparticles and carbon-supported indium nanoparticles under mild conditions is described. Physicochemical characterization by X-ray diffraction (XRD), X-ray photoelectron microscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed heterogeneous morphologies for the In nanoparticles in all cases. Apart from In0, XPS revealed the presence of oxidized In species on the carbon-supported samples, whereas these species were not observed for the unsupported samples. The best-in-class catalyst (In50/C50) exhibited a high formate Faradaic efficiency (FE) near the unit (above 97%) at -1.6 V vs. Ag/AgCl, achieving a stable current density around -10 mA·cmgeo-2, in a common H-cell. While In0 sites are the main active sites for the reaction, the presence of oxidized In species could play a role in the improved performance of the supported samples.

Catalytic gas-phase hydrogenation of CO2 into CH4 was tested under three different nickel/aluminate catalysts obtained from precursors of hexaaluminate composition (MAl16O19, M = Mg, Ca, Ba). These catalysts were prepared using a carbon template method, where carbon is self-generated from a sol-gel that contains an excess of citric acid and the Al and M salts (Ba2+, Ca2+, Mg2+) by two-step calcination in an inert/oxidizing atmosphere. This procedure yielded Ni particles decorating the surface of a porous high surface area matrix, which presents a typical XRD pattern of aluminate structure. Ni particles are obtained with a homogeneous distribution over the surface and an average diameter of ca 25–30 nm. Obtained materials exhibit a high conversion of CO2 below 500 °C, yielding CH4 as a final product with selectivity >95%. The observed trend with the alkaline earth cation follows the order NiBaAlO-PRx > NiCaAlO-PRx > NiMgAlO-PRx. We propose that the high performance of the NiBaAlO sample is derived from both an appropriate distribution of Ni particle size and the presence of BaCO3, acting as a CO2 buffer in the process.

Methanol carbonylation was evaluated over heterogeneous catalysts based on Cu-exchanged zeolitic materials with different topology: Cu@MOR, Cu@FER, and Cu@ZSM-5. Despite the similar Si/Al ratios, it is crucial to acknowledge that the acid strength is influenced by the framework topology, as supported by the NH3-TPD results. This, along with other characterization techniques allowed us to estimate the impact of pore size and pore distribution in these microporous materials on catalytic performance. The channel structure influenced catalytic parameters such as conversion and selectivity. The higher methanol conversion achieved on Cu@FER shows the importance of Brønsted acid sites and redox centres location regarding the topology of the material. Concerning the selectivity, the production of acetic acid was endorsed by the 12-MR (MOR) channels, methyl acetate's production by the 10-MR (FER) channels. Finally, the presence of 6-MR (ZSM-5) channels led to a complete selectivity towards DME production. The reaction mechanism was elucidated via operando DRIFTS-MS and results revealed a bifunctional mechanism in which methanol adsorbs and dehydrates on acidic Brønsted sites and CO is activated over Cu+ species.

Ni-Mg/Al mixed oxide catalysts (Ni2Al, Ni2Mg1Al, and Ni1Mg1Al) obtained from layered double hydroxides (LDHs) were tested on the one-pot production of tetrahydrofurfuryl alcohol (TFA) from furfural (FF). Upon calcination at 400 °C and reduction at 500 °C, the LDHs gave catalysts containing small nickel crystallites (<4 nm) dispersed on mixtures of metal oxides and spinel structures. Complete conversion of FF (>99.5%) was achieved on all the catalysts after 4 h at 190 °C and 5.0 MPa of H2 using 5 wt.% FF in ethanol and a furfural-to-catalyst mass ratio of 7.44 g/g. TFA evolved from the sequential hydrogenation of FF to furfuryl alcohol (FA) to TFA. Competing reaction routes involved decarbonylation of FF to furan (FUR) followed by hydrogenation to tetrahydrofuran (THF) or hydrogenolysis to n-butane (BU) and the hydrogenation of the carbonyl group in FF to form 2-methyl furan (mFUR) and its hydrogenation to 2-methyltetrahydrofuran (mTHF). A third competing route consisted of the nucleophilic addition of FF with ethanol and with FA to form acetals (such as 2-(diethoxymethyl)furan, FDA), which were later converted to difurfuryl ether (DFE) and tetrahydrofurfuryl ethyl ether (TFEE) as final products. Hydrogen pressure favored the production of TFA and diminished the formation of acetals, while temperature reduced the capacity of the catalyst to hydrogenate the furan ring, thus reducing TFA and increasing FA and FUR. An 80% yield to TFA was achieved with the Ni2Mg1Al catalysts after 6 h at 190 °C and 50 bar H2, but a variety of coproducts were present at low concentration. Testing of the catalysts in gas-phase hydrogenation conditions at atmospheric pressure revealed a poorer performance, with FA as the main product.

A critical query on literature is the approach used to immobilize homogeneous catalysts to improve their efficiency and recyclability. This work aims to compare the immobilization level of a kind of Pd-N,N′-bis(salicylidene)-o-phenylenediamine complex on high surfaces of polymeric resins to provide heterogenous catalysts for Mizorocki-Heck reaction. The preparation method involves two strategies: (i) polymerization of the ligand before the complex-synthesis in a “multi-step (MS)” approach and (ii) a direct “one-step” (OS) immobilization by polymerization of the metal-containing monomers (MCMs) as co-monomer. Both approaches effectively yield polymers with a larger surface area, over 700 m2 g−1, and suitable thermic properties to use in the proposed reaction. In addition, the characterization of the polymers by XRD, XPS, and TEM demonstrates notable differences in Pd species on polymer support associated with the methodological approach to immobilizing the metal complex.

Copper is considered an excellent alternative to noble-metal selective hydrogenation catalysts. Herein, we systematically studied the effect of Cu nanoparticle size (2–10 nm) in the selective hydrogenation of 1,3-butadiene in excess of propene. The catalysts exhibited particle size-dependent activity, with particles above 4 nm being 3 to 4 times more active than the 2 nm ones, and at the same time more selective (up to 99 % at almost full butadiene conversion for 7–10 nm particles). The higher activity of larger particles was ascribed to a higher fraction of kinks and step sites, essential to activate hydrogen. The high selectivity of nanoparticulate Cu catalysts was explained by a very strong preferential adsorption of 1,3-butadiene compared to mono-olefin adsorption on the Cu surface (in particular on larger particles), as proven via adsorption measurements. These findings may guide both testing and catalyst design for reactions where hydrogen surface availability and selectivity play a key role.

Perovskite-based oxides demonstrate a great catalytic efficiency in advanced oxidation processes (AOPs), where both free and non-free radical pathways may occur. The non-free radical pathway is preferable because it is less affected by the wastewater environment, yet little is known about its origin. Here, we exploit Ruddlesden-Popper (RP) layered perovskite oxides as an excellent platform for investigating the structure-property relationship for peroxymonosulfate (PMS) activation in AOPs. The atomic-level interaction of the perovskite and rock salt layers in RP oxides stabilizes the transition metals at low valences, causing the formation of abundant lattice oxygen/interstitial oxygen species. Unlike oxygen vacancies in conventional perovskites, which promote free-radical generation, these reactive oxygen species in RP perovskites have high activity and mobility and facilitate the formation of non-free radical singlet oxygen. This singlet oxygen reaction pathway is optimized by tailoring the oxygen species, leading to the discovery of LaSrCo0.8Fe0.2O4 with exceptionally efficient PMS activation.

In this work it has been studied the effect different polymers (or also the same polymer with different properties) can make in the preparation of catalysts Ni-La/Al2O3 by the wet impregnation with excess of water. In order to do that, the catalysts were first prepared with the method “All in one”, a method that was developed in our laboratory group. This method consists on the preparation of aqueous suspensions with every component to obtain the final catalyst: the support, the precursor salt of the active material and the additives, were polymers are introduced. The method allows us to create the catalysts in suspensions that can be used directly for the structured substrates coating, or after drying and calcinating this suspensions, slurried catalysts in powder form can be obtained to use them for each characterization technique. After preparing the aqueous suspensions, they were characterised by viscosimetry in order to find out the changes on the viscosity made by the addition of the different polymers, and after drying and calcinating them, the obtained slurried catalysts were characterized by different techniques: N2 physisorption, CO chemisorption, temperature programmed reduction and X-ray diffraction. This characterization was made to study the effect of the added polymer in the catalyst, which was supposed to improve the effect on the Sabatier’s reaction. The results show that depending on the polymer added to the catalyst formulation, the utility of this would change, also that with the addition of the same polymer, modifying the molecular weight or the hydrolysis degree, the results obtained would be different, making some polymers more useful than others. On the other hand, it had been previously discovered that the use of polyvynil alcohol (PVA) and Ni content influences directly in the properties of catalysts obtained by the “All in one” method. PVA allows to control nickels particle size managing to have a higher dispersion and, as a consequence, th

Sawdust is an abundant but poorly utilized lignocellulosic side stream. It is mainly burned as energy despite the fact that it could be utilized in the production of biomass-based chemicals. Sawdust is composed of cellulose, hemicellulose, and lignin fractions, all of which can be separated and utilized for different applications. The production of so-called high-value-added chemicals from biomass could improve the economics associated with biorefinery and replace certain petroleum-based chemicals as well. Recently, the production of 5-hydroxymethylfurfural (HMF) and furfural has attracted a considerable amount of interest, as these substances can be prepared from sawdust-based sugars and play a key role in the production of many biomass-based products. The catalytic conversion of sawdust-based sugars into HMF and furfural was studied in this thesis. The comprehensive utilization of sawdust through stepwise fractionation, hydrolysis, and conversion were used, and all the reaction steps were geared toward high selectivity. In addition, different homogeneous and heterogeneous catalysts, such as mineral acids, organic acids, metal salts, catalysts based on activated carbon (AC), and deep eutectic solvents (DESs), were also utilized in this research. In the first part of the thesis, sawdust was selectively degraded to produce either hemicellulose sugars or furfural using acid hydrolysis or DES treatment. In the second part, sawdust-based sugars were converted into HMF and furfural using different AC-based catalysts or DES media. Based on the results obtained, it was demonstrated that hemicellulose could be efficiently separated as sugars and furfural from the sawdust. These processes could potentially be utilized in biorefinery concepts where the main products are currently obtained from cellulose. In addition, the selectivity of HMF and furfural production from sawdust-based sugars could be significantly improved with the use of AC catalysts in the conversion, Tiivistelmä Sahanpuru on laajasti saatavilla oleva mutta huonosti hyödynnetty lignoselluloosapitoinen sivuvirta. Se poltetaan pääasiassa energiana, vaikka se voitaisiin hyötykäyttää erilaisten biomassaperäisten tuotteiden valmistuksessa. Sahanpuru koostuu selluloosa-, hemiselluloosa- ja ligniinifraktioista, jotka voidaan erottaa toisistaan ja hyötykäyttää erilaisissa sovelluksissa. Niin sanottujen korkean lisäarvon tuotteiden valmistaminen biomassasta voisi sekä lisätä biojalostamoiden taloudellista kannattavuutta että korvata osan öljypohjaisista tuotteista biomassaperäisillä vastineilla. Viime aikoina 5-hydroksimetyylifurfuraalin (HMF) ja furfuraalin tuotanto on herättänyt paljon kiinnostusta, sillä ne voidaan valmistaa sahanpurun sisältämistä sokereista ja niillä on keskeinen rooli monien biomassaan perustuvien tuotteiden valmistuksessa. Tässä työssä tutkittiin sahanpurun sisältämien sokereiden katalyyttistä konversiota HMF:ksi ja furfuraaliksi. Sahanpuru hyödynnettiin kokonaisvaltaisesti vaiheittaisen fraktioinnin, hydrolyysin ja konversion avulla siten, että reaktioiden korkea selektiivisyys säilyi joka vaiheessa. Työssä hyödynnettiin erilaisia homogeenisia sekä heterogeenisiä katalyyttejä, kuten mineraalihappoja, orgaanisia happoja, metallisuoloja, aktiivihiilipohjaisia katalyyttejä ja syväeutektisia liuottimia (DES). Työn ensimmäisessä osassa sahanpurun hemiselluloosafraktio pilkottiin selektiivisesti joko sokereiksi tai furfuraaliksi. Tähän käytettiin happohydrolyysiä tai DES-käsittelyä. Työn toisessa osassa sahanpurun sisältämiä sokereita muunnettiin HMF:ksi ja furfuraaliksi käyttäen erilaisia aktiivihiilikatalyyttejä tai hyödyntäen syväeutektisia liuottimia. Saadut tulokset osoittivat, että hemiselluloosa voidaan erottaa sahanpurusta selektiivisesti sekä sokereina että furfuraalina. Tämä olisi hyödynnettävissä esimerkiksi biojalostamoissa, joissa nykyiset päätuotteet saadaan selluloosasta. Lisäksi tulokset osoittivat että HMF- ja furfuraalituotannon selekt

Natural gas (Methane) is currently the primary source of catalytic hydrogen production, accounting for three quarters of the annual global dedicated hydrogen production (about 70 M tons). Steam–methane reforming (SMR) is the currently used industrial process for hydrogen production. However, the SMR process suffers with insufficient catalytic activity, low long-term stability, and excessive energy input, mostly due to the handling of large amount of CO2 coproduced. With the demand for anticipated hydrogen production to reach 122.5 M tons in 2024, novel and upgraded catalytic processes are desired for more effective utilization of precious natural resources. In this review, we summarized the major descriptors of catalyst and reaction engineering of the SMR process and compared the SMR process with its derivative technologies, such as dry reforming with CO2 (DRM), partial oxidation with O2, autothermal reforming with H2 O and O2. Finally, we discussed the new progresses of methane conversion: direct decomposition to hydrogen and solid carbon and selective oxidation in mild conditions to hydrogen containing liquid organics (i.e., methanol, formic acid, and acetic acid), which serve as alternative hydrogen carriers. We hope this review will help to achieve a whole picture of catalytic hydrogen production from methane.

Achieving the goal of living in a sustainable and greener society, will need the chemical industry to move away from petroleum-based refineries to bio-refineries. This aim can be achieved by using biomass as the feedstock to produce platform chemicals. A platformchemical, 2,5-furandicarboxylic acid (FDCA) has gainedmuch attention in recent years because of its chemical attributes as it can be used to produce green polymers such polyethylene 2,5-furandicarboxylate (PEF) that is an alternative to polyethylene terephthalate (PET) produced from fossil fuel. Typically, 5-(hydroxymethyl)furfural (HMF), an intermediate product of the acid dehydration of sugars, can be used as a precursor for the production of FDCA, and this transformation reaction has been extensively studied using both homogeneous and heterogeneous catalysts in different reaction media such as basic, neutral, and acidic media. In addition to the use of catalysts, conversion of HMF to FDCA occurs in the presence of oxidants such as air, O2, H2O2, and t-BuOOH. Among them, O2 has been the preferred oxidant due to its low cost and availability. However, due to the low stability of HMF and high processing cost to convert HMF to FDCA, researchers are studying the direct conversion of carbohydrates and biomass using both a single- and multi-phase approach for FDCA production. As there are issues arising from FDCA purification, much attention is now being paid to produce FDCA derivatives such as 2, 5-furandicarboxylic acid dimethyl ester (FDCDM) to circumvent these problems. Despite these technical barriers, what is pivotal to achieve in a cost-effective manner high yields of FDCA and derivatives, is the design of highly efficient, stable, and selective multi-functional catalysts. In this review, we summarize in detail the advances in the reaction chemistry, catalysts, and operating conditions for FDCA production from sugars and carbohydrates.

In this study, conversion of xylose to furfural was studied using lignin-based activated carbon-supported iron catalysts. First, three activated carbon supports were prepared from hydrolysis lignin with different activation methods. The supports were modified with different metal precursors and metal concentrations into five iron catalysts. The prepared catalysts were studied in furfural production from xylose using different reaction temperatures and times. The best results were achieved with a 4 wt% iron-containing catalyst, 5Fe-ACs, which produced a 57% furfural yield, 92% xylose conversion and 65% reaction selectivity at 170 °C in 3 h. The amount of Fe in 5Fe-ACs was only 3.6 µmol and using this amount of homogeneous FeCl₃ as a catalyst, reduced the furfural yield, xylose conversion and selectivity. Good catalytic activity of 5Fe-ACs could be associated with iron oxide and hydroxyl groups on the catalyst surface. Based on the recycling experiments, the prepared catalyst needs some improvements to increase its stability but it is a feasible alternative to homogeneous FeCl₃.

[EN] We first studied the reactivity of H2O vapor in metal-organic frameworks (MOFs) with Pt nanocrystals (NCs) through the water-gas shift (WGS) reaction. A water-stable MOF, UiO-66, serves as a highly effective support material for the WGS reaction compared with ZrO2. The origin of the high catalytic performance was investigated using in situ IR spectroscopy. In addition, from a comparison of the catalytic activities of Pt on UiO-66, where Pt NCs are located on the surface of UiO-66 and Pt@UiO-66, where Pt NCs are coated with UiO-66, we found that the competitive effects of H2O condensation and diffusion in the UiO-66 play important roles in the catalytic activity of Pt NCs. A thinner UiO-66 coating further enhanced the WGS reaction activity of Pt NCs by minimizing the negative effect of slow H2O diffusion in UiO-66.

Despite the global positive impacts of soybean-, maize- and sugarcane-based (first-generation) liquid biofuels, several drawbacks pertaining to increased use of agricultural land, causing deforestation in some countries and extensive practice of fertilizers have been observed. As a result, developing advanced (second- and third-generation) liquid biofuels have been identified as better alternatives and are considered to be of great importance in the future. These alternative biofuels will help to meet the energy demand by transition to ameliorate and fulfil the energy demand, especially in the transport sector.The actual energy demand for fossil fuels in Bolivia is unsustainable due to its continuous increase. Bolivia has its own fossil fuel resources, but these still fall short of demand, forcing the government to budget for yearly fuel imports. This situation has prompted attempts to achieve energy independence through the production of biofuels. However, it is important that Bolivian energy independence endeavours include a sustainable vision. Bolivia has great potential for local first- and second-generation liquid biofuel production. However, the intensification of liquid biofuel production should focus on second- and third-generation biofuel production to minimize direct and indirect undesired impacts.This thesis considers the development of suitable technology and procedures to produce second-generation liquid biofuels, which can be divided into biodiesel and ethanol production. The proposed biodiesel production includes the development of heterogeneous catalysts that enable the production of biodiesel from edible and non-edible oils (i.e. rapeseed, babassu, and Ricinus oils). These heterogeneous catalysts are based on gel-based mayenite and alumina supports with the co-precipitation of metal oxides of calcium, lithium, magnesium and tin. The synthesized catalysts were characterized using, N2 physisorption, X-ray powder diffraction, scanning electron microsco, Trots globala positiva effekter med användningen av flytande biobränslen som härrör från sojabönor, majs och sockerrör, har flera nackdelar observerats genom ökad användning av jordbruksmark, avskogning och ibland omfattande användning av gödningsmedel. Som ett resultat av detta har utvecklingen av andra generationens biobränslen identifierats som ett bättre alternativ med stor betydelse i framtiden. Andra och tredjegenerationens biodrivmedel kommer att hjälpa till att möta energibehovet särskilt inom transportsektorn.Det faktiska energibehovet och ökningen av fossilbränslen i Bolivia är ohållbart. Bolivia har egna fossilbränsleresurser, men dessa är för dyra att exploatera, vilket tvingar regeringen att budgetera för årlig bränsleimport. Man har även satsat storskaligt på inhemsk naturgas för att bli självförsörjande på energi. Det är dock viktigt att bolivianska energi-oberoende innefattar en hållbar vision. Bolivia har stor potential för lokal produktion av flytande biodrivmedel från både första och andra generationens biobränslen. Intensifieringen av produktion av biodrivmedel bör dock fokusera på andra och tredjegenerationens biobränsle för att minimera global klimatpåverkan.Denna avhandling avser utveckling av lämplig teknik för att producera andra generationens flytande biodrivmedel i Bolivia för både biodiesel och etanol. Den föreslagna biodieselproduktionen innefattar utvecklingen av heterogena katalysatorer för produktion av biodiesel från ätbara och oätbara oljor (raps, babassu och ricinoljor). Dessa katalysatorer är baserade på mayenit- och aluminiumoxid som bärare med olika metalloxider såsom kalcium, litium, magnesium och tenn. De syntetiserade katalysatorerna karakteriserades med kväve-fysisorption, röntgenpulverdiffraktion, svepelektronmikroskopi och termogravimetrisk analys (TGA). Tester i labskala visar att användandet av heterogen katalys för biodieselproduktion med högre utbyten mellan 85% till 100% är möjlig. För produktion av etanol studerades, This project was funded by the Swedish International Development Cooperation Agency (SIDA) together with UMSS Universidad Mayor de San Simon, Polygeneration systems in Bolivia: Integrated energy technologies for rural development

[EN] Three families of organosiliceous materials with different structuration level, order, and textural properties (non-ordered, M41S, and SBA-15 type materials) were prepared incorporating in their structural framework chiral pyrrolidine units with variable content. Likewise, non-ordered mesoporous hybrid solids were obtained through a sol-gel process in a fluoride medium, while M41S and SBA-15 type materials were obtained through micellar routes in the presence of long-chain neutral surfactants or block copolymers. Thanks to appropriate characterization studies and catalytic tests for the Michael addition between butyraldehyde and beta-nitrostyrene, we showed how the void shapes and sizes present in the structure of hybrid materials control the diffusion of reactants and products, as well as confine transition states and reactive intermediates. The best catalytic results, considering activity and enantioselectivity, were achieved in the presence of a non-ordered material, NOH-Pyr-5%, which exhibited the highest Brunauer-Emmett-Teller (BET) area, with a 96% yield and a 82% ee for the Michael adduct.

The process of oxidative condensation of methanol with acetic acid to acrylic acid on B–P–V–W–Ox/SiO2 catalyst modified by hydrothermal method has been studied. Modification of the catalyst by hydrothermal treatment of the carrier changes its physical and chemical properties, and therefore its catalytic properties. The influence of the main technological parameters – temperature, contact time and ratio of reagents on the selectivity and yield of the reaction products and on the conversion of acetic acid has been studied when hydrothermally treated catalyst was used. The best time of contact was 8 sec. which allows to reach the highest selectivity and yield of acrylic acid and methyl acrylate. The highest catalytic activity of the designed catalyst is observed at the reaction temperature of 673 K, however, it is impossible to increase temperature over this value due to the limited thermal stability of the catalyst and the sharp increase in the formation of complete oxidation products. With an increase of methanol part in the ratio of reagents (methanol: acetic acid) to 1,2:1, the selectivity of acrylic acid and methyl acrylate increases, and the selectivity of by-products is significantly reduced. The highest yield of the target products in the reaction of oxidative condensation of methanol with acetic acid is observed at a ratio of oxygen: acetic acid 1,5:1. The growth of the oxygen: acetic acid ratio promotes reduce of acetone and methyl acetate selectivity but does not change the selectivity of methyl acrylate and significantly increases the selectivity and yield of acrylic acid. At the best conditions of the reaction it was possible to achieve 54.7 % total yield of acrylic acid and methyl acrylate. Due to the wide availability and relatively low cost of the initial reagents (methanol and acetic acid), the synthesis of acrylic acid by the oxidative condensation of methanol with acetic acid in the presence of the developed catalyst is very promising, Исследован процесс окислительной конденсации метанола с уксусной кислотой в акриловую кислоту на B–P–V–W–Ox/SiO2 катализаторе, модифицированном гидротермальным методом. Модификация катализатора путем гидротермальной обработки носителя изменяет его физико-химические, а, следовательно, и каталитические свойства. Исследовано влияние основных технологических параметров – температуры, времени контакта и соотношение реагентов на селективность, выход продуктов реакции и на конверсию уксусной кислоты при использовании гидротермально обработанного катализатора. Лучшим по селективности образования и выходу акриловой кислоты и метилакрилата есть время контакта 8 с. Самые высокие показатели каталитической активности разработанного катализатора наблюдаются при температуре реакции 673 K, однако, невозможным является дальнейшее повышение температуры из-за ограниченной термическую устойчивость катализатора и резкий рост образования продуктов полного окисления. При увеличении доли метанола в соотношении реагентов (метанол: уксусная кислота) до 1,2:1 возрастает селективность образования акриловой кислоты и метилакрилата, и существенно уменьшается селективность образования побочных продуктов. Наибольший выход целевых продуктов в реакции окислительной конденсации метанола с уксусной кислотой наблюдается при соотношении кислород: уксусная кислота 1,5:1. Рост соотношения кислород: уксусная кислота способствует уменьшению селективности образования ацетона и метилацетата, не изменяет селективность образования метилакрилата и существенно увеличивает селективность образования и выход акриловой кислоты. В лучших условиях реакции удалось достичь суммарного выхода акриловой кислоты и метилакрилата 54,7 %. Несмотря на широкую доступность и сравнительно низкую стоимость исходных реагентов (метанола и уксусной кислоты) синтез акриловой кислоты методом окислительной конденсации метанола с уксусной кислотой в присутствии разработанного катализатора является весьма перспективным, Досліджено процес окиснювальної конденсації метанолу з оцтовою кислотою в акрилову кислоту на B–P–V–W–Ox/SiO2каталізаторі, модифікованому гідротермальним методом. Модифікація каталізатора шляхом гідротермальної обробки носія змінює його фізико-хімічні, а отже, і каталітичні властивості. Досліджено вплив основних технологічних параметрів – температури, часу контакту і співвідношення реагентів на селективність та вихід продуктів реакції та на конверсію оцтової кислоти при використанні гідротермально обробленого каталізатора.. Кращим за селективністю утворення та виходом акрилової кислоти і метилакрилату є час контакту 8 с. Найвищі показники каталітичної активності розробленого каталізатора спостерігаються при температурі реакції 673 K, проте, неможливим є подальше підвищення температури через обмежену термічну стійкість каталізатора та різке зростання утворення продуктів повного окиснення. При збільшенні частки метанолу в співвідношенні реагентів (метанол : оцтова кислота) до 1,2:1 зростає селективність утворення акрилової кислоти і метилакрилату, та суттєво зменшується селективність утворення побічних продуктів. Найвищий вихід цільових продуктів в реакції окиснювальної конденсації метанолу з оцтовою кислотою спостерігається при співвідношенні кисень : оцтова кислота 1,5:1. Ріст співвідношення кисень : оцтова кислота сприяє зменшенню селективності утворення ацетону та метилацетату, не змінює селективність утворення метилакрилату і суттєво збільшує селективність утворення та вихід акрилової кислоти. В кращих умовах реакції вдалося досягти сумарного виходу акрилової кислоти та метилакрилату 54,7 %. Зважаючи на широку доступність та порівняно низьку вартість вихідних реагентів (метанолу та оцтової кислоти) синтез акрилової кислоти методом окиснювальної конденсації метанолу з оцтовою кислотою в присутності розробленого каталізатора є вельми перспективним

The production of H2 from the so-called Liquid Organic Hydrogen Carriers (LOHC) has recently received great focus as an auspicious option to conventional hydrogen storage technologies. Among them, formic acid, the simplest carboxylic acid, has recently emerged as one of the most promising candidates. Catalysts based on Pd nanoparticles are the most fruitfully investigated, and, more specifically, excellent results have been achieved with bimetallic PdAg-based catalytic systems. The enhancement displayed by PdAg catalysts as compared to the monometallic counterpart is ascribed to several effects, such as the formation of electron-rich Pd species or the increased resistance against CO-poisoning. Aside from the features of the metal active phases, the properties of the selected support also play an important role in determining the final catalytic performance. Among them, the use of carbon materials has resulted in great interest by virtue of their outstanding properties and versatility. In the present review, some of the most representative investigations dealing with the design of high-performance PdAg bimetallic heterogeneous catalysts are summarised, paying attention to the impact of the features of the support in the final ability of the catalysts towards the production of H2 from formic acid.

Precise control of the three-dimensional (3D) structure of highly dispersed metal species such as metal complexes and clusters attached to an oxide surface has been important for the development of next-generation high-performance heterogeneous catalysts. However, this is not easily achieved for the following reasons. (1) Metal species are easily aggregated on an oxide surface, which makes it difficult to control their size and orientation definitely. (2) Determination of the 3D structure of the metal species on an oxide powder surface is hardly possible. To overcome these difficulties, we have developed the premodified surface method, where prior to metal deposition, the oxide surface is premodified with a functional organic molecule that can strongly coordinate to a metal atom. This method has successfully provided a single metal dispersion on an oxide single-crystal surface with the 3D structure precisely determined by polarization-dependent total reflection fluorescence X-ray absorption fine structure (PTRF-XAFS). Here we describe our recent results on ultra-high dispersions of various metal atoms on TiO2(110) surfaces premodified with mercapto compounds, and show the possibility of fine tuning and orientation control of the surface metal 3D structures.

The direct catalytic esterification of amides that leads to the construction of C-O bonds through the cleavage of amide C-N bonds is a highly attractive strategy in organic synthesis. While aliphatic and aromatic alcohols can be readily used for the alcoholysis of activated and unactivated amides, the introduction of phenols is more challenging due to their lower nucleophilicity in the phenolysis of unactivated amides. Herein, we demonstrate that phenols can be used for the phenolysis of unactivated amides into the corresponding phenolic esters using a simple heterogenous catalytic system based on CeO2 under additive-free reaction conditions. The method tolerates a broad variety of functional groups (>50 examples) in the substrates. Results of kinetic studies afforded mechanistic insights into the principles governing this reaction, suggesting that the cooperative effects of the acid-base functions of catalysts would be of paramount importance for the efficient progression of the C-N bond breaking process, and consequently, CeO2 showed the best catalytic performance among the catalysts explored.

Precise control of the three-dimensional (3D) structure of highly dispersed metal species such as metal complexes and clusters attached to an oxide surface has been important for the development of next-generation high-performance heterogeneous catalysts. However, this is not easily achieved for the following reasons. (1) Metal species are easily aggregated on an oxide surface, which makes it difficult to control their size and orientation definitely. (2) Determination of the 3D structure of the metal species on an oxide powder surface is hardly possible. To overcome these difficulties, we have developed the premodified surface method, where prior to metal deposition, the oxide surface is premodified with a functional organic molecule that can strongly coordinate to a metal atom. This method has successfully provided a single metal dispersion on an oxide single-crystal surface with the 3D structure precisely determined by polarization-dependent total reflection fluorescence X-ray absorption fine structure (PTRF-XAFS). Here we describe our recent results on ultra-high dispersions of various metal atoms on TiO2(110) surfaces premodified with mercapto compounds, and show the possibility of fine tuning and orientation control of the surface metal 3D structures.

Metal and nitrogen co-doped carbons (M-N/Cs) have emerged as promising alternatives to platinum-based catalysts for the oxygen reduction reaction (ORR). Here, density functional theory calculations are used to investigate the adsorption of anions and impurities from the electrolyte on the active site, modelled as an M-N4 motif embedded in a planar carbon sheet (M= Cr , Mn, Fe , Co). The two-dimensional catalyst structure implies that each metal atom has two potential active sites, one on each side of the sheet. Adsorption of anions or impurities on both sites results in poisoning, but adsorption on one of the sites leads to a modified ORR activity on the remaining site. The calculated adsorption energies show that a number of species adsorb on one of the two sites only under realistic experimental conditions. A few of these adsorbates furthermore modify the adsorption energies of the ORR intermediates on the remaining site in such a way that the limiting potential is improved.

This dissertation is part of the research performed within the project ON 172061. Laboratories used: Laboratory for Applied and industrial chemistry and Laboratory for organic analysis and synthesis of the Department of Chemistry of the Faculty of Science and Mathematics in Nis, Laboratory of the Faculty of Technology in Novi Sad and Laboratories of the Institute for nuclear sciences "Vinca", University of Belgrade. The aim of this doctoral dissertation is chemical synthesis of the Al2O3-based catalyst in the form of powder. The catalysts were synthesized by modified (sol-gel, reflux and hydrothermal) method. In addition, the chemical modification of the catalyst based on Al2O3 was carried out with the selected dopant/modificator (KI). The optimal conditions for the synthesis, modification and activation of the catalyst, as well as the selection of precursors for the synthesis of the catalyst (aluminum-isopropoxide and aluminum-trisecbutoxide), were examined. Complete physico-chemical characterization of synthesized catalysts was performed (analysis of textural, structural, morphological, thermal and surface properties of catalysts). The catalysts were tested in the reaction of transesterification of sunflower oil with methanol. The influence of a large number of process parameters (reaction temperature, pressure, velocity and type of mixing, mass fraction of the catalyst, molar ratio of reactants, influence of co-solvent(s), etc.) on the reaction yield were studied. The kinetics of the reaction, the reuse of the catalyst, catalyst regeneration and the stability of the catalyst were examined. The physicochemical characteristics of the synthesized catalytic materials have been correlated to the catalytic activity in the reaction of transesterification of sunflower oil.

The catalytic performances of two different classes of catalysts containing nickel or/and ruthenium as the active sites were studied in the depolymerisation of lignin isolated from Miscanthus × giganteus. The catalysts were prepared either by coprecipitation (ie, (RuNiMgAlO)x, (RuNiAlO)x, (NiAlO)x, (NiMgAlO)x) or by wet impregnation (ie, Ru/Al2O3) and characterized by nitrogen physisorption (BET), XRD, XPS, NH3-TPD, Raman and H2-TPR techniques. The experimental results indicate that the presence of ruthenium led to dimers as dominant products., Bio4Energy

Ga/H-MFI was prepared by vapor-phase reaction of GaCl3 with Brønsted acid O-H groups in dehydrated H-MFI zeolite. The resulting [GaCl2]+ cations in the as-exchanged zeolite are treated in H2 at 823 K to stoichiometrically remove Cl ligands and form [GaH2]+ cations. Subsequent oxidation in O2 and characterization by IR spectroscopy and NH3-temperature-programmed desorption (TPD) suggests that, for Ga/Al ratios ≤0.3, Ga3+ exists predominantly as [Ga(OH)2]+-H+ cation pairs and to a lesser degree as [Ga(OH)]2+ cations at low Ga/Al ratios (∼0.1); while both species are associated with proximate cation-exchange sites, calculated free energies of formation suggest that [Ga(OH)]2+ cations are more stable on cation-exchange sites associated with NNN (next-nearest neighbor) framework Al atoms than on those associated with NNNN (next-next-nearest neighbor) framework Al atoms. Ga K-edge X-ray Absorption Near Edge Spectroscopy (XANES) measurements indicate that, under oxidizing conditions and for all Ga/Al ratios, all Ga species are in the +3 oxidation state and are tetrahedrally coordinated to 4 O atoms. Fourier analysis of Ga K-edge Extended X-ray Absorption Fine Structure (EXAFS) data supports the conclusion that Ga3+ is present predominantly as [Ga(OH)2]+ cations (or [Ga(OH)2]+-H+ cation pairs). For Ga/Al ratios ≤0.3, wavelet analysis of EXAFS data provide evidence for backscattering from nearest neighboring O atoms and from next-nearest neighboring framework Al atoms. For Ga/Al > 0.3, backscattering from next-nearest neighboring Ga atoms is also evident, characteristic of GaOx species. Upon reduction in H2, the oxidized Ga3+ species produce [Ga(OH)H]+-H+ cation pairs, [GaH2]+-H+ cation pairs, and [GaH]2+ cations. Computed phase diagrams indicate that the thermodynamic stability of the reduced Ga3+ species depends sensitively on temperature, Al-Al interatomic distance, and H2 and H2O partial pressures. For Ga/Al ratios ≤0.2, it is concluded that [GaH2]+-H+ cation pairs an

"This is the peer reviewed version of the following article: Simion, Andrada, Natalia Candu, Simona M. Coman, Ana Primo, Ivan Esteve-Adell, Véronique Michelet, Vasile I. Parvulescu, and Hermenegildo Garcia. 2018. Bimetallic Oriented (Au /Cu2 O) vs. Monometallic 1.1.1 Au (0) or 2.0.0 Cu2 O Graphene-Supported Nanoplatelets as Very Efficient Catalysts for Michael and Henry Additions. European Journal of Organic Chemistry 2018 (44). Wiley: 6185 90. doi:10.1002/ejoc.201801443, which has been published in final form at https://doi.org/10.1002/ejoc.201801443. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.", [EN] Michael and Henry addition reactions have been investigated using mono (Au and Cu2O) and bimetallic nanoplatelets (Au/Cu2O) grafted onto few-layers graphene (fl-G) films as heterogeneous catalysts by comparison with homogeneous NaOH and K2CO3 ones. In the presence of the heterogeneous catalysts, these reactions occurred in the absence of any extrinsic (NaOH and K2CO3) base with turnover numbers (TONs) at least four orders of magnitude higher. While the homogeneous catalysts provided TONs close to the unity for Au/Cu2O/fl-G this was of the order of 10(7). These reactions also occurred with a very good selectivity to the targeted products. These performances are in line with the basicity of these catalysts demonstrated from CO2 chemisorption measurements. The effect of the nanosize and the interaction of the nanoparticles with the graphene are also important to achieve this high activity.

A fast and simple synthetic route towards a new family of poly(ionic liquids) based on aromatic crosslinked poly(azomethine-pyridinium) salts is described. These new polymers were prepared in one step from new diamine methyl pyridinium salts and isopthaldehyde, in 30 min under microwave irradiation. By this method, poly(azomethine-pyridinium) containing chloride (Cl), bis(trifluoromethylsulfonyl)imide (TFSI) and hexaflorophosphate (PF6) as counter-anions were synthetized. This new pyridinium poly(ionic liquid)s were obtained as insoluble powders showing high thermal stability. The poly(azomethine-pyridinium)s were tested as heterogeneous catalysts in the cycloaddition of CO2 to epichlorohydrin to obtain chloropropylene carbonate. The polymers containing chloride anion shows high content of catalytically active sites and the best performance of the series, with 100% selectivity towards the chloropropylene carbonate in a reaction without solvent at 3 bar of CO2, 100 °C and low catalyst loading (0.5 mol%).

The oxidation of adamantane with hydrogen peroxide catalyzed by zirconia-supported 11-molybdovanado­phospho­ric acid is shown to be a suitable green route for the synthesis of adamantanol and adamantanone. This work evaluates how the catalyst activity and selectivity are affected by some of its preparative parameters, such as the method for supporting the catalytically active heteropoly acid over the zirconia matrix or the pretreatments applied to the resulting materials before being used as heterogeneous catalysts. Our results indicate that the most effective catalysts able to maintain their activity after several reaction runs are those prepared by following the sol-gel route, whereas the most selective catalysts are those obtained by impregnation methods. Moreover, the calcination temperature has also been identified as a relevant parameter influencing the performance of catalysts based on supported heteropoly acids. The increasing catalytic activity observed over several consecutive reaction runs has been attributed to the formation of peroxo derivatives of polyoxometalate clusters at the surface of the catalyst and their accumulation after each reaction cycle.

Currently, surfactants (also called surface-active agent) are high production volume chemical compounds thanks to their wide range of applications, not only in the detergent industry, but also in other industrial sectors such as the pharmaceutical, food, agrochemical, textile, and perfume industry. Over the last few decades, the depletion of fossil fuels and the environmental problems caused by their combustion have been a big concern, that made the search for new sources of energy and chemical products necessary. Among them, the biomass, which is an abundant and renewable resource, is the most important source of carbon compounds since it provides ¿platform chemicals¿, highly functionalised molecules that come from carbohydrates or triglycerides. This work shows the synthesis of amphiphilic molecules, the polar and non-polar part of those compounds is formed by the combination of platform chemicals (5-hydroxymethylfurfural (HMF), glycerol and fatty alcohols) through reactions of etherification and acetalization in the presence of acid heterogeneous catalysts., Actualmente, los surfactantes o tensioactivos son compuestos con un elevado volumen de producción por su aplicación no solo en la industria de los detergentes, sino también en otros sectores como en la industria farmacéutica, alimentaria, agroquímica, textil, y perfumes. En las últimas décadas, la preocupación por el agotamiento del petróleo y los problemas medioambientales asociados a su combustión, ha dado lugar a la búsqueda de nuevas fuentes de energía y de productos químicos. Entre ellas, la biomasa, recurso abundante y renovable, constituye la única fuente de compuestos de carbono a través de las moléculas plataforma, moléculas altamente funcionalizadas que provienen de carbohidratos o triglicéridos. En este trabajo se ha llevado a cabo la síntesis de moléculas antipáticas cuya parte polar y apolar está formada por la combinación de moléculas plataforma (5-hidroximetilfurfural, glicerina y alcoholes grasos) unidas mediante reacciones de eterificación y acetalización en presencia de catalizadores ácidos heterogéneos.

Titania based catalyst and TiO2 doped with zirconia were prepared by modified sol-gel method. The synthesized catalysts samples were characterized by BET, XRD, SEM and FTIR techniques. Photocatalytic activity was tested in the reaction of crystal violet (CV) dye decolorization/decomposition under UV light irradiation. The effect of several operational parameters, such as catalyst dosage, initial dye concentrations, duration of UV irradiation treatment and number of reaction cycles were also considered. The obtained results indicated faster dye decolorization with the increase of the catalyst amount and a decrease of initial CV concentrations. An influence of doping with zirconia on the physico-chemical properties of bare titania was studied. The doping procedure had affected photocatalytic properties of the final catalytic material, and had improved photocatalytic performances of doped catalyst on crystal violet decolorization/degradation in comparison to bare titania.

Co3O4 particles were supported on a series of activated carbons (G60, CNR, RX3, and RB3). Incipient wetness method was used to prepare these catalysts. The effect of the structural and surface properties of the carbonaceous supports during oxidation of benzyl alcohol was evaluated. The synthetized catalysts were characterized via IR, TEM, TGA/MS, XRD, TPR, AAS, XPS, and N2 adsorption/desorption isotherm techniques. Co3O4/G60 and Co3O4/RX3 catalysts have high activity and selectivity on the oxidation reaction reaching conversions above 90% after 6 h, without the presence of promoters. Catalytic performances show that differences in chemistry of support surface play an important role in activity and suggest that the presence of different ratios of species of cobalt and oxygenated groups on surface in Co3O4/G60 and Co3O4/RX3 catalysts, offered a larger effect synergic between both active phase and support increasing their catalytic activity when compared to the other tested catalysts.

Furfural is a valuable chemical, the production of furfural from renewable biomass resources becomes more attractive in recent years. In this study, biomass fast pyrolysis with heterogeneous catalysts (titanium compounds (TiN, TiO2 and TiOSO4) and metal nitrides (MoN, GaN and VN)) for furfural production was investigated experimentally by means of pyrolysis-gas chromatography/mass-spectrometry (Py-GC/MS). The measurement results indicated that TiN and GaN promoted the furfural compounds production notably mainly through direct decomposition of oligosaccharides. The formation of furfural was promoted when the amount of TiN was increased, and the yield of furfural formed was about 5.5 times the size of that from non-catalytic pyrolysis when TiN/cellulose mass ratio was 4. The furfural yield decreased when the pyrolysis residence time increased from 10 to 30 s, which suggests competitive reactions (formation of 1, 6-anhydro-beta.-D-glucopyranose) against the formation of furfural. TiN, as a catalyst for fast pyrolysis towards furfural production, can be well applied to agriculture biomass residues. Comparing three biomass residues: corncob, wheat straw and cotton stalk, corncob showed higher furfural yield due to the higher holocellulose content, while wheat straw showed higher furfural selectivity.

Ni and Cu mono- and bimetallic catalysts modified with various types of acid oxides MOx (M=Mo, V, W, and Re) were tested for the hydrogenolysis of glycidol as an alternative route to the hydrogenolysis of glycerol to obtain 1,3-propanediol (1,3-PrD). Characterization results revealed that the presence of modifiers affected the dispersion and reducibility of the NiO particles and the strength and amount of acid sites. Among the modifiers tested, Re led to the highest activity, a high propanediols selectivity, and the highest 1,3-PrD/1,2-propanediol (1,2-PrD) ratio. The Ni-Cu/Re ratio was optimized to improve the catalytic activity. The best catalytic result, with a 46% 1,3-PrD yield and a 1,3-PrD/1,2-PrD ratio of 1.24, was obtained if the monometallic Ni catalyst at 40wt% loading and modified with 7wt% Re was used at 393K and 5MPa H-2 pressure after 4h of reaction. The overall 1,3-PrD yield starting from glycerol and assuming a two-step synthesis (glycerolglycidol1,3-PrD) and a yield of 78% for the first step would be 36%. This 1,3-PD yield is the highest for a reaction catalyzed by a non-noble metal and is comparable to the direct hydrogenolysis of glycerol using noble metal catalysts at a longer time and a high H-2 pressure.

Peak Force Tapping-mode AFM is used to investigate the three-dimensional morphology of RuO2 nanoparticles supported on a solid surface, with sub-nanometer spatial resolution. Samples were prepared by spin coating (i) a drop of RuO2 colloidal suspension onto a mica sheet, followed by further treatments (drying, calcination and/or reduction), and (ii) a second drop of colloidal suspension on fresh, dried or calcined RuO2-mica. RuO2 crystallites are supported with a certain distribution of sizes, and this heterogeneity is essentially maintained after high-temperature treatments. After calcination, single coated RuO2-mica samples present small RuO2 crystallites (4.5 nm height) as well as nanorod-like assemblies (14 nm height). A disaggregation of particles occurs during the reduction treatment. Double coating RuO2 over non-calcined RuO2-mica samples involves mechanical effects causing re-dispersion of supported clusters. An intermediate drying step is unable to prevent re-dispersion of particles and even leads to repulsion between dehydrate RuO2 supported particles and hydrated particles in suspension. Meanwhile, a calcination step prevents re-dispersion and promotes growth of supported crystallites. Nanorods formed by single RuO2 deposition exhibit mostly regular flat surfaces, while a second RuO2 deposition on calcined RuO2-mica samples leads to larger nanorods with stepped surfaces (terraces), a favourable geometry for ammonia synthesis reaction. © 2015 Elsevier B.V. All rights reserved.

In this study, modified sol-gel method was employed to synthesize the pure and Zr-doped titania catalysts. Brunauer-Emmett-Teller (BET) method was applied to determine porosity, X-ray diffraction (XRD) analysis was used to study crystal structure, scanning electron microscopy (SEM) was used to investigate morphology and Fourier transform infrared spectroscopy (FTIR) was used to examine surface properties/total acidity of the obtained catalysts samples. Photocatalytic activity was tested in the reaction of crystal violet (CV) dye decolourization/degradation under UV light irradiation. The effects of several photocatalysis operational parameters were considered, such as catalyst dosage, initial dye concentrations, duration of UV irradiation treatment, as well as catalysts calcination temperatures and dopant amounts. The obtained results indicated faster dye decolourization/degradation with the increase of the catalyst dosage and the decrease of initial CV concentrations. The Zr-doping affects photocatalytic properties, i.e. CV decolourization/degradation of the prepared catalytic materials. Thus, addition of 5 wt.% of ZrO2 to titania increases photocatalytic effect for similar to 15% and addition of 10 wt.% of ZrO2 improves the photocatalytic efficiency of titania for nearly 30%.

El Capítulo I trata la actual crisis energética y hace una breve introducción sobre el uso del hidrógeno como vector energético, mencionando los diferentes métodos que pueden utilizarse para la producción/purificación de hidrógeno a partir de recursos renovables. También incluye una breve descripción del papel que puede jugar la biomasa como alternativa a los combustibles fósiles, y su conversión a biocombustibles y productos químicos de valor añadido. El reformado catalítico de glicerol para la producción de gas de síntesis o corrientes ricas en hidrógeno se presenta como una ruta potencial, alternativa y prometedora que ha llamado la atención en los últimos años. Esta reacción se suele llevar a cabo sobre catalizadores basados en metales soportados en materiales estables. En el Capítulo II se estudia el efecto de la adición de Sn sobre las propiedades y la estabilidad de catalizadores de Pt soportado en carbón en la reacción de reformado glicerol en fase gas. Para ello, se preparó y caracterizó una serie de catalizadores con diferentes relaciones atómicas Pt/Sn. El alto precio de los metales nobles motiva la búsqueda y empleo de metales más baratos y abundantes que también tengan un buen comportamiento catalítico en esta reacción. Por ello, en el Capítulo III se emplearon catalizadores basados en Ni promovidos por óxido de cerio para el reformado de glicerol. Por otro lado, se hace necesario optimizar el uso del CeO2 debido a su limitada disponibilidad y sus extensas aplicaciones. Así, en este trabajo se dispersó CeO2 sobre carbón activado de alta área superficial, obteniendo gran superficie de óxido de cerio expuesta al mismo tiempo que se redujo su consumo. También se estudió el efecto de la presencia de estaño en estos catalizadores. Se obtienen diversas ventajas al realizar el reformado de glicerol en fase líquida. Así, se obtienen corrientes más ricas en H2 con menor cantidad de CO. Esto se debe a las moderadas temperaturas y altas presiones empleadas, que fa

In this manuscript, the application of different nanocatalysts derived from metal oxides impregnated on the surface of the magnetite in different reaction of general interest in Organic Chemistry is described. In the First Chapter, a cobalt derived catalyst was used to study the hydroacylation reaction of azodicarboxylates with aldehydes. In the Second Chapter, a catalyst derived from copper was used to perform different reactions, including homocoupling of terminal alkynes and the subsequent hydration reaction to obtain the corresponding 2,5-disubstituted benzofurans, the reaction of alcohols and amines (or nitroarenes) to obtain the corresponding aromatic imines, the cross-dehydrogenative coupling reaction of N-substituted tetrahydroisoquinolines using deep eutectic solvents and air as final oxidant. Finally, the formation of benzofurans from aldehydes and alkynes through a tandem coupling-allenylation-cyclization process has been performed. In the Third Chapter, a bimetallic catalyst derived from nickel and copper was used to study the multicomponent reaction between benzyl bromides, sodium azide and alkynes to obtain the corresponding triazoles. In the Fourth Chapter, a catalyst derived from palladium was used in the direct arylation of heterocycles using iodonium salts. Also the synthesis of 4-aryl coumarins through the Heck arylation reaction and subsequent cyclization using the same catalyst is described. In the last Chapter, the use of different eutectic mixtures were studied as alternative media to perform in a single vessel the cyclation reaction of N-hydroxy imidoyl chlorides and alkynes, without any type of catalyst under oxidizing conditions.