Oximes are important intermediates in organic synthesis and they have been used as building blocks in many organic transformations. They are used in the synthesis of N-substituted amides by Beckmann rearrangement or in the production of plastics, synthetic fibers, and pharmaceutical derivatives. With respect to their biological properties, oximes may act as bactericide, insecticide, herbicide, and fungicide, with the advantage of often having low toxicity. The traditional method to prepare oximes is the reaction of a carbonyl compound with an excess of hydroxylamine hydrochloride in the presence of a stoichiometric amount of base. However, both isomeric oximes (Z and E) are usually produced, except in the case of symmetrical ketones. The oxime stereochemistry is important for their physical and pharmacological properties, as well as their reactivity. Therefore, a method for controlling the stereochemistry of oximes is always required.

We described herein the use of diaryl diselenide and selenium dioxide as a catalyst in the double bond C-N isomerization of oximes. The reactions were performed using selenium dioxide and different species of diaryl diselenides with a range of ketoximes in green conditions. Several analysis using NMR equipment, such as ¹H-NMR, ¹³C-NMR, ⁷⁷Se-NMR, DEPT 135, COSY, HSQC, HMQC, HBQC and NOESY were performed to follow the reaction to discover intermediates and the interaction sites between the catalyst and the reactant.

In this work, a new ecological approach to the selenofunctionalization of alkenes has been described. Using I₂ as catalyst, DMSO as oxidant, under microwave irradiation (MW) in a solvent- and metal-free method. The general idea is to combine organoselenium compounds and triazole nuclei to obtain molecules capable of becoming a powerful class due to their potential pharmacological activity. However, most methods that involve the functionalization of alkenes are generally mediated by the use of transition metals or reagents in large stoichiometric quantities. Thus, the development of direct, clean and environmentally appropriate procedures, which are in accordance with the principles of Green Chemistry, for the synthesis of these compounds remains highly desirable. Thus, the present work developed the synthesis of β-amino selenides with only 20 minutes of reaction time, following the conditions previously mentioned. After several tests, the optimized condition observed provided a yield of 89% for the product. To verify the viability of the methodology, a variation of 9 diselenides and 11 alkenes was used, obtaining a total of 20 molecules, with yields ranged from 27 to 89%. All synthesized compounds have been fully characterized. In addition, encouraged by these results, the scope of the reaction was expanded using also diorganoil disulfides and ditellurides, obtaining more 13 different molecules with good to excellent yields. Finally, compared to traditional methods, our methodology is a lightweight, metal-free, simple and practical tool for selenofunctionalization of alkenes and is considered a promising alternative in the development of new drugs with potential biological activities.

The development of microkinetic models allows gaining an understanding of fundamental catalyst surface phenomena in terms of elementary reaction steps without defining a priori a rate-determining step, yielding more meaningful reaction rates. This work aimed at developing such a microkinetic model that accurately describes the Water-Gas Shift (WGS) reaction, i.e., one of the major routes for hydrogen production, over cobalt (Co) catalysts supported on multi-walled carbon nanotubes (MWCNTs). Co is a sulfur-tolerant active phase, and the functionalized MWCNT support has exceptional conductivity properties and defects that facilitate electron transfer on its surface. The model was formulated based on a well-known mechanism for the WGS reaction involving the highly reactive carboxyl (COOH*) intermediate. The kinetic parameters were either estimated or computed from theoretical prediction models (such as the Collision and Transition-State theory). The derived system of differential-algebraic equations was solved using the DDAPLUS package available in AthenaVISUAL Studio. The developed model was capable of simulating the experimental data (R² = 0.96), presenting statistically significant kinetic parameters. Furthermore, some of the catalysts descriptors introduced in the model were experimentally determined by characterization techniques, such as the specific surface area (S_P = 22000 m²/kg_cat) and the density of active sites (σ = 0.012 mol_{Act.Surf.­­­­}/kg_cat). The characterization results along with the model confirm that the COOH* formation reaction (CO* + OH* → COOH* + *) is the rate-determining step and explain the optimal catalyst performance at elevated temperatures (350-450^oC) and space times (70-80 kg.s/mol), as indicated by the experimental results.

Indazoles are fused azaheterocycles with wide applicability in the medical field. In the last decades, the pharmacology interest in this nucleus has increased due to a variety of compounds that show biological activities. Among them are antipyretic, analgesic, anti-inflammatory, antimicrobial, anti-HIV, anti-hypertensive, anti-tumour, anti-fungal and lately is used as an inhibitor of bacterial β-gyrase and a selective estrogen receptor. In addition, organochalcogen compounds have been widely explored due to their possible use as biologically active agents, or as key intermediates and catalysts in organic synthesis.

Based on this and due to our continuous interest in the preparation of nitrogen-functionalized organochalcogen compounds, we describe herein our results on the synthesis of 3-(arylselanyl)- and (arylsulfenyl)-2H-indazoles by molecular iodine-catalyzed. Through the reaction of 2H-indazoles and a diverse range of diorganyl diselenides and diorganyl disulfates using catalytic amount of I₂ (5 mol%) in DMSO (3.0 equiv.) as oxidant at 100 °C. This protocol proved to be simple, efficient and highly chalcogenated regioselectively at the C3 position to furnish a range of corresponding products selectively substituted 3-(organochalcogenyl)-2H-indazoles. A total of 15 examples were synthesized in good to excellent yields (36 to 98 % ). The products were obtained through a solvent and metal free methodology under mild conditions.

The development of an innovative and sustainable high-throughput reaction platform allows to optimize a wide range of chemical processes (materials synthesis, catalysis, among others) to tackle the Green Deal. This tool unifies for the first time the benefits of mechanical energy, thermal and pressure activation, continuous flow with an induction in-situ heating system, facilitating the incorporation of inputs (liquids, solids and gases) with controlled pressure.

As result of synergistic effect of this simultaneous activation, this technology will: i) shorten reaction times; ii) decrease temperature; iii) improve reactions kinetics as mass transfer limitations are reduced; iv) minimize the use of solvents; v) decrease the reaction steps; v) increase volume treated, enabling a real scale-up; and vi) enhance the yields and/or selectivity [1-3].

In the present communication, the new high-throughput reactor is used for the synthesis of Calcium diglyceroxide (CaDG), minimizing the reaction steps and cost, to obtain a pure CaDG. This heterogeneous catalyst is used for biodiesel production and valorise the glycerol produced. An efficient synthesis protocol of CaDG has been patented, requiring shorter time, without heating and no need of solvents [4]. The transesterification reaction of used and refined vegetable oils has also been optimised with CaDG as solid catalyst, using the same new reactor that promotes the oil-methanol mixing, minimizing the mass transfer problems associated to the immiscibility of reactants [5]. Low methanol:oil ratios and low temperature can be used with the high-throughput reactor even with used oils and in plant pilot scale under flow conditions [6].

Glucaric acid (GA) is one of the top 12 value added chemicals from biomass and this is due to the several applications that this molecule and its derivates can have in the industrial fields. For this reason, it is interesting to find a competitive way to produce it from lignocellulosic feedstock, more in details from glucose. Therefore, our research is focused on the synthesis of GA starting from Glucose in aqueous phase, using molecular oxygen as oxidant agent and gold nanoparticles supported materials as catalysts. All the tests have been carried out in a batch reactor and the catalysts have been prepared using the sol-immobilization method. The role of the stabilizer (polyvinyl alcohol-PVA) has been studied by varying systematically the amount of PVA in the colloidal synthesis and therefore how it could affect (i) the final morphology of the preformed supported metal nanoparticles and (ii) and the catalytic performance in terms of activity, yield and stability; high amount of PVA facilitates the formation of small nanoparticles (no PVA 7.8nm vs PVA2,4 2,61nm) but also block the active site of the catalyst, giving lower GA yield (22% vs 17%). For this reason, it has been evaluated two different method to partially remove the PVA, a washing step and several heat treatments, and seems that best results are obtained with the washing and the HT at 120℃ while at 200°C -250°C the average crystallite size increased giving a lower yield of GA

Levulinic acid and its esters (LE) are polyfunctional molecules that can be obtained from lignocellulosic biomass. Herein, the catalytic conversion of methyl and ethyl levulinates into γ-valerolactone (GVL) via catalytic transfer hydrogenation (CTH) by using methanol, ethanol, and 2-propanol as the H-donor/solvent, was investigated under both batch and gas-flow conditions. In particular, high-surface-area, tetragonal zirconia has proven to be a suitable catalyst for this reaction. Under batch conditions, 2-propanol was found to be the best H-donor, with ethyl levulinate giving the highest yield in GVL. However, high autogenic pressures are needed in order to work in the liquid phase at high temperature with light alcohols. The reactions occurring under continuous gas-flow conditions, at atmospheric pressure, were found to be much more efficient, also showing excellent GVL yields when EtOH was used as the reducing agent (GVL yield of around 70% under optimized conditions). However, the deposition of heavy carbonaceous compounds over the catalytic surface, in this way blocking the active Lewis acid sites, led to a progressive change in the chemo-selectivity, promoting the alcoholysis of angelica lactones back to LE. Nevertheless, the in situ regeneration of the catalyst, performed by feeding air at 400 °C for 2 h, allows an almost complete recovery of the initial catalytic behaviour, proving that the deactivation is reversible. The reaction has been tested also using a true bioethanol, derived from agricultural waste. These results represent the very first examples of the CTH of LE under continuous gas-flow conditions reported in literature.

Removal of hydrogen sulfide (H₂S) from gas streams with varying overall pressure and H₂S concentration is a long-standing challenge faced by oil and gas industries. The present work focuses on H₂S capture using metal-organic frameworks (MOFs), in an effort to shed light on their potential as adsorbents in the field of gas storage and separation. MOFs hold great promise as they make possible the design of structures from organic and inorganic units but also, they have provided an answer to a long-time challenging objective, i.e., how to design extended structures of materials. Moreover, the functionalization of the MOF’s surface can result in increased H₂­S uptake. For example, the insertion of 1% of a fluorinated linker in MIL-101(Cr)-4F(1%) allows for enhanced H₂S capture. Although noticeable efforts have been made in studying the adsorption capacity of H₂S using MOFs, there is a clear need for gaining a deeper understanding in terms of their thermal conductivities and specific heats in order to design more stable adsorption beds, experiencing high exothermicity. Simply put, the exothermic nature of adsorption means that sharp rises in temperature can negatively affect the bed stability in the absence of sufficient heat transfer. The work presented herein provides a detailed discussion, by thoroughly combining the existing literature, on new developments in MOFs for H₂S removal, and tries to provide insight into new areas for further research.

Nowadays, the development of catalytic technologies to transform biomass-derived platform molecules, like 5-hydroxymethylfurfural (5-HMF) obtained from the dehydration of C6 carbohydrates (glucose, fructose, galactose, among others), into valuable products with interesting industrial and commercial applications, is attracting the interest of many research groups. Thus, for instance, 5-ethoxymethylfurfural (EMF), which can be produced from the etherification of 5-HMF with ethanol, can be mixed with petro-diesel, being considered as one of the most promising furan derivatives, not only as diesel additive but also as a biofuel. In this context, this communication deals with the evaluation of the catalytic performance of different commercial ion-exchange resins, as solid acid catalysts, in this etherification reaction. The objective was to elucidate the role of acid sites (type: Lewis and/or Brönsted, concentration and strength) in this catalytic process. Moreover, it must be taken into account that the etherification of 5-HMF into EMF also generates, as the main sub-product, ethyl levulinate, that can also be produced by esterification of levulinic acid and ethanol through acid catalysis. The most relevant experimental parameters will be optimized in order to achieve the highest EMF yield. Moreover, special attention will be paid to develop active, selective and stable heterogeneous catalysts.

The depletion of fossil fuels and the growing concerns related to the environmental impact of their processing has progressively switched the interest towards the utilisation of biomass-derived materials for a large variety of processes. Among them, biogas, which is a CH₄-rich gas deriving from anaerobic digestion of biomass, has acquired a lot of interest as feedstock for reforming processes. The main issue in employing biogas is related to the carbon deposition and metal sintering, which are both responsible for the deactivation of the catalyst. In this work, bimetallic and monometallic Rh and Ni based formulation were supported on alumina and ceria with the aim of evaluating their activity and stability in biogas oxidative steam reforming. Rh/Al₂O₃ sample showed the highest activity towards the reaction and Rh addition to Ni/Al₂O₃ formulation enhances its catalytic performances; nevertheless, this induced a remarkably higher coke deposition in the 24-hours stability test. For this reason, ceria was selected as support for further investigations. The initial activity of the CeO₂-supported catalysts was found to be close to the Al₂O₃-supported catalyst. Then, 50-hours stability tests were performed and a reduction in the activity was observed. Nevertheless, TPO analysis demonstrated that no coke was present on the catalyst surface, thanks to ceria oxygen mobility properties. The deactivation was in fact ascribable to the sintering of the active species, which have a worse dispersion on ceria rather than on alumina because of the lower SSA of the support.