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Glucose is the most abundant monosaccharide as it is the primary unit of cellulose and starch, which are the more relevant feedstocks for biorefineries. Dehydration of glucose can lead to anhydroglucoses, whose interest has been increasing due to its potential industrial use. Commercial sulfonic polymer resins and a synthesized organic–inorganic mesoporous material were taken as Brønsted acid catalysts. High hexose conversion (up to 98%) and selectivity to anhydroglucoses (~80%) could be reached, turning this process into an alternative route to carbohydrate pyrolysis that presents an energy-intensive downstream. Hexose conversion to anhydroglucoses was related to the amount of acid sites, and the removal of one molecule of water from hexoses to produce anhydroglucoses was found as the preferential dehydration route over a bare Brønsted acid catalyst in anhydrous polar aprotic solvent (DMF) at mild conditions. Product distribution changed dramatically upon catalyst deactivation with HMF and fructose emerging as relevant products. It was suggested that an additional Lewis surface is produced during the deactivation process, probably arising from the formation of insoluble high molecular weight compounds in acidic media. Full article

This review analyzes TiO₂-based coatings formed by the plasma electrolytic oxidation (PEO) process of titanium for the photocatalytic degradation of methyl orange (MO) under simulated solar irradiation conditions. PEO is recognized as a useful technique for creating oxide coatings on various metals, particularly titanium, to assist in the degradation of organic pollutants. TiO₂-based photocatalysts in the form of coatings are more practical than TiO₂-based photocatalysts in the form of powder because the photocatalyst does not need to be recycled and reused after wastewater degradation treatment, which is an expensive and time-consuming process. In addition, the main advantage of PEO in the synthesis of TiO₂-based photocatalysts is its short processing time (a few minutes), as it excludes the annealing step needed to convert the amorphous TiO₂ into a crystalline phase, a prerequisite for a possible photocatalytic application. Pure TiO₂ coatings formed by PEO have a low photocatalytic efficiency in the degradation of MO, which is due to the rapid recombination of the photo-generated electron/hole pairs. In this review, recent advances in the sensitization of TiO₂ with narrow band gap semiconductors (WO₃, SnO₂, CdS, Sb₂O₃, Bi₂O₃, and Al₂TiO₅), doping with rare earth ions (example Eu³⁺) and transition metals (Mn, Ni, Co, Fe) are summarized as an effective strategy to reduce the recombination of photo-generated electron/hole pairs and to improve the photocatalytic efficiency of TiO₂ coatings. Full article

Cu₂O, a narrow-bandgap semiconductor with visible light absorption capabilities, faces limitations in photocatalytic applications due to photocorrosion from hole self-oxidation and insufficient light absorption. In this work, a series of novel spherical Cu₂O/FePO₄ Z-scheme heterojunctions were successfully synthesized via self-assembly to overcome these challenges. The photocurrent, electrical impedance spectroscopy (EIS), and photoluminescence (PL) tests showed that Cu₂O/1.5FePO₄ (CF1.5) had excellent electron hole separation efficiency. Subsequently, photocatalytic degradation was utilized as a probing technique to further confirm the above conclusions, with the kinetic reaction constants of CF1.5 being 2.46 and 11.23 times higher than those of Cu₂O and FePO₄, respectively. After five cycles of experiments and XPS analysis, it was found that the content of Cu(I) in CF1.5 did not significantly decrease after the reaction, indicating that it has superior anti-photocorrosion performance compared to single Cu₂O, which is also due to the establishment of a Z-scheme heterojunction. Systematic studies using radical scavenging experiments and ESR tests identified ·OH and ·O₂⁻ as the main active species involved in photocatalysis. The formation of a Z-scheme heterojunction not only enhances the photocatalytic activity of the CF1.5 composite but also effectively suppresses the photocorrosion of Cu₂O, thereby offering a promising approach for enhancing anti-photocorrosion of Cu₂O. Full article

The development of heterostructures incorporating photocatalysts optimized for visible-light activity represents a major breakthrough in the field of environmental remediation research, offering innovative and sustainable solutions for environmental purification. This study explores the photocatalytic capabilities of a SnFe₂O₄/g-C₃N₄ heterojunction nanocomposite, successfully synthesized from graphitic carbon nitride (g-C₃N₄) and tin ferrate (SnFe₂O₄) and applied to the degradation of the cationic dye brilliant cresyl blue (BCB) in an aqueous solution. These two components are particularly attractive due to their low cost and ease of fabrication. Various characterization techniques, including XRD, FTIR, SEM, and TEM, were used to confirm the successful integration of SnFe₂O₄ and g-C₃N₄ phases in the synthesized catalysts. The photocatalytic and photo-Fenton-like activity of the heterojunction composites was evaluated by the degradation of brilliant cresyl blue under visible LED illumination. Compared to the pure components SnFe₂O₄ and g-C₃N₄, the SnFe₂O₄/g-C₃N₄ nanocomposite demonstrated a superior photocatalytic performance. Furthermore, the photo-Fenton-like performance of the composites is much higher than the photocatalytic performances. The significant improvement in photo-Fenton activity is attributed to the synergistic effect between SnFe₂O₄ and g-C₃N₄, as well as the efficient separation of photoexcited electron/hole pairs. The recyclability of the SnFe₂O₄/g-C₃N₄ composite toward BCB photo-Fenton like degradation was also shown. This study aimed to assess the modeling and optimization of photo-Fenton-like removal BCB using the SnFe₂O₄/g-C₃N₄ nanomaterial. The main parameters (photocatalyst dose, initial dye concentration, H₂O₂ volume, and reaction time) affecting this system were modeled by two approaches: a response surface methodology (RSM) based on a Box–Behnken design and artificial neural network (ANN). A comparison was made between the predictive accuracy of RSM for brilliant cresyl blue (BCB) removal and that of the artificial neural network (ANN) approach. Both methodologies provided satisfactory and comparable predictions, achieving R² values of 0.97 for RSM and 0.99 for ANN. Full article

A heterogeneous polybenzimidazole-supported Mo(VI) catalyst and tert-butyl hydroperoxide (TBHP) as an oxidising reagent have been utilised to establish a more environmentally friendly and greener alkene epoxidation process. A polybenzimidazole-supported Mo(VI) complex (PBI.Mo) has been prepared, characterised and evaluated successfully. The stability and catalytic activity of the produced catalyst have been evaluated for the epoxidation of 1,7-octadiene and 1,5-hexadiene in a jacketed stirred batch reactor to assess its performance towards these alkenes. The suitability and efficiency of the catalyst have been compared by studying the effect of reaction temperature, feed mole ratio of alkene to TBHP, catalyst loading, and reaction time on the yield of 1,2-epoxy-5-hexene and 1,2-epoxy-7-octene. Response surface methodology (RSM) using Box–Behnken Design (BBD) has been employed to design experimental runs and study the catalytic performance of the PBI.Mo catalyst for all batch experimental results. A quadratic regression model has been developed representing an empirical relationship between reaction variables and response, which is the yield of epoxides. The numerical optimisation technique concluded that the maximum yield that can be reached is 66.22% for 1,7-octadiene and 64.2% for 1,5-hexadiene. The reactivity of alkenes was observed to follow the sequence 1,5-hexadiene > 1,7-octadiene. The findings of this study confirm that the optimal reaction conditions vary between the two reactions, indicating differences in catalytic performance for each alkene. Full article

In this work, we studied the main decomposition reactions on the ground state of nitromethane (CH₃NO₂) with the CASPT2 approach. The energetics of the main elementary reactions of the title molecule have been analyzed on the basis of Gibbs free energies obtained from standard expressions of statistical thermodynamics. In addition, we describe a mapping method (orthogonalized 3D representation) for the potential energy surfaces (PESs) by defining an orthonormal basis consisting of two $R^n$ orthonormal vectors (n, internal degrees of freedom) that allows us to obtain a set of ordered points in the plane (vector subspace) spanned by such a basis. Geometries and harmonic frequencies of all species and orthogonalized 3D representations of the PESs have been computed with the CASPT2 approach. It is found that all of the analyzed kinetically controlled reactions of nitromethane are endergonic. For such a class of reactions, the dissociation of nitromethane into CH₃ and NO₂ is the process with the lower activation energy barrier (ΔG); that is, the C-N bond cleavage is the most favorable process. In contrast, there exists a dynamically controlled process that evolves through a roaming reaction mechanism and is an exergonic reaction at high temperatures: CH₃NO₂ → [CH₃^…NO₂]* → [CH₃ONO]* → CH₃O + NO. The above assertions are supported by CASPT2 mappings of the potential energy surfaces (PESs) and classical trajectories obtained by “on-the fly” CASSCF molecular dynamics calculations. Full article

We describe the design and synthesis of a series of 7-(N-aryl pyrrolidinyl) indoles and oxo-analogs as isosteric mimics of the DCAF15 binder E7820, a well-known member of aryl sulfonamides known as SPLAMs. The functionalization of C-7 in indoles was achieved by metal-catalyzed CH-activation with unexpected results. Binding assays revealed the pyrrolidine N-aryl carboxylic acid analog to be as equally active as E7820. Full article

In this work, tin and zinc salts of silicotungstic and phosphotungstic acids were synthesized, characterized, and tested as catalysts for esterification reactions of glycerol with acetic acid (HOAc) to produce glycerol esters such as monoacetyl glycerol (MAG), which are used as additives in the pharmaceutical and food industries and in the manufacturing of explosives, or, in the case of di- or triacetyl glycerol (DAG and TAG), green bioadditives for diesel or gasoline. The activity of metal-exchanged salts (Zn, Sn) in H₃PW₁₂O₄₀ and H₄SiW₁₂O₄₀ heteropolyacids was evaluated in esterification reactions at room temperature. Among the catalysts tested, Sn_2/3PW₁₂O₄₀ was the most active and selective toward the glycerol esters. The process’s selectivity can be controlled by changes to reaction conditions. The maximum selectivitiesy of DAG and TAG were 60% and 30%, respectively, using a 1:3 molar ratio of glycerol/HOAc and a Sn_3/2PW₁₂O₄₀/673 K catalyst load of 0.4 mol%. Under these conditions, a glycerol conversion rate of 95% was observed and selectivity towards DAG and TAG was observed at 60% and 30%, respectively. The results were achieved after an 8 h reaction at a temperature of 333 K. The Sn_3/2PW₁₂O₄₀/673 K catalyst demonstrated the highest efficiency, which was attributed to its higher degree of acidity. Full article

This study combines experimental and density functional theory (DFT) to evaluate the influence of alkaline cation characteristics on the electronic structure and photodegradation efficacy of organic dyes in MNbO₃ (M = Na, K) perovskites. The X-ray Photoelectron Spectroscopy (XPS) and X-ray Absorption Near Edge Spectroscopy (XANES) spectra at the Nb edge of the Perovskites were employed to characterize its chemical and structural properties. The DFT calculations were carried out to simulate XANES spectra as well as the structural and electrical properties of KNbO₃ and NaNbO₃. Our results show that the simulated and experimental XANES spectra are similar, indicating that the computational simulations were able to capture the local structure of the niobate samples. In addition, a photocatalytic experiment was conducted to benchmark the methylene blue consumption efficiency between different niobates. The findings demonstrated that KNbO₃ is more efficient than NaNbO₃ for methylene blue UV photocatalytic degradation, which is associated with their electronic properties. This arises as a direct result of the variably deformed NbO₆ octahedra resulting from the different alkali used. Our findings facilitate the advancement of stable and abundantly available photocatalysts, which may be employed for energy-intensive processes such as the mineralization of organic water pollutants and hydrogen production by water splitting. Full article

The palladium-catalyzed cross-coupling reaction used for carbon–carbon bond formation is one of the most commonly applied reactions in modern organic synthesis. In this work, a concise strategy was developed for constructing the tetrahydroisoquinoline core, a key structural motif found in many biologically active compounds. This method involves the palladium-catalyzed intramolecular coupling of aryl iodides with ester enolates generated in the presence of K₃PO₄ as a base, resulting in the formation of the tetrahydroisoquinoline ring with an exceptionally high yield of 84%. Full article

In this study, the application of the response surface method was used to determine the best reaction conditions of the gas-phase hydrogenation of carbon dioxide on a commercial nickel-based catalyst. The procedural goals included the choice and tests of the robustness of the statistical method that could improve the achievement of the goal of the process, first of all by reducing the number of necessary experiments. The outcome goal for the process under consideration was the optimization of reaction conditions for mild reaction conditions and the stoichiometric deficiency of hydrogen; these reaction conditions are rarely presented in the literature (despite their potential advantages). Both goals were achieved with a successful result. To find optimal reaction conditions, only 36 experiments were carried out. This is a very good result, taking into account the insufficient information in the literature, which means that it is a difficult task to deduce the region of the highest carbon dioxide conversion. The maximum carbon dioxide conversion was obtained for a temperature of 318 °C and a ratio of molar fluxes of H₂ to CO₂ equal to 3.5. It should be emphasized that this result was confirmed experimentally. Full article

Glycerol is a biogenic waste that is generated in both the biodiesel and oleo-chemical industries. The value addition of surplus glycerol is of utmost importance for making these industries economically profitable. In line with this, glycerol is converted into glycerol carbonate, a potential candidate for the industrial production of polymers and biobased non-isocyanate polyurethanes. In addition, glycerol can also be converted into solketal, which is the protected form of glycerol with a primary hydroxyl functional group. In this contribution, we developed a microwave-assisted solvent and catalyst-free method for converting solketal into solketal carbonate. Under conventional heating conditions, the reaction of solketal with dimethyl carbonate resulted in 70% solketal carbonate in 48 h. However, under microwave heating, 90% solketal carbonate was obtained in just 30 min. From the perspective of sustainability and green chemistry, biomass-derived heterogeneous catalysts are gaining importance. Therefore, in this project, several green catalysts, such as molecular sieves (MS, 4Å), Hβ-Zeolite, Montmorillonite K-10 clay, activated carbon from groundnut shell (Arachis hypogaea), biochar prepared from the pyrolysis of sawdust, and silica gel, were successfully used for the carbonyl transfer reaction. The obtained solketal carbonate was thoroughly characterized by ¹H NMR, ¹³C NMR, IR, and MS. The method presented here is facile, clean, and environmentally benign, as it eliminates the use of complicated procedures, toxic solvents, and toxic catalysts. Full article

Cerium oxide nanoparticles (CeO₂-NPs) offer promising advantages in semiconductors and biomedical applications due to their optical, electrical, antioxidant, and antibacterial properties. However, the widely reported synthetic strategies for CeO₂-NPs demand toxic precursors and intermediary pollutants, representing a major limitation to CeO₂-NPs applications. Therefore, it is necessary to develop greener strategies that implicate ecological precursors to reduce the negative impact on the scalability of CeO₂-NPs. In this regard, we applied Lycium cooperi (L. cooperi) aqueous extracts as an unexplored potential green reducing agent for the eco-friendly synthesis of CeO₂-NPs. The L. cooperi extract showed the presence of alkaloids, flavonoids, cardiac glycosides, and carbohydrate-derived families, which were assessed for spherical monodispersed CeO₂-NPs under a rapid chemical reduction. Moreover, the elemental composition revealed Ce and O, indicating highly pure CeO₂-NPs characterized by an interplanar cubic crystalline structure. Furthermore, we detected the presence of stabilizing functional groups from L. cooperi, which, after a controlled annealing process, resulted in a band gap energy of 3.9 eV, which was optimal for the CeO₂-NPs. Thus, the results indicate that L. cooperi is an environmentally friendly synthesis method that can open a new route for CeO₂-NPs in biomedical and industrial applications. Full article

Metallic Pd/Ni gauzes, located downstream of the Pt/Rh ammonia oxidation catalyst nets in the Ostwald process, is the current technology for capturing volatile gas phase platinum and rhodium species lost from the Pt/Rh combustion catalyst through evaporation. In this screening study, we explore four oxide families, ABO₃ perovskites, (ABO₃)_n(AO) Ruddlesden–Popper (RP) phases, AO rock salt, and A₂O₃ sesquioxide type oxides, as alternative materials for platinum capture. It was found that all the tested nickelates, LaNiO₃, NdNiO₃, La₂NiO₄, and La₄Ni₃O₁₀, captured platinum well and formed A₂NiPtO₆. In contrast, La_0.85Sr_0.15FeO₃, LaFeO₃, and LaCoO₃ did not capture platinum. CaO, SrO, and Nd₂O₃ formed low-dimensional platinates such as Ca_xPt₃O₄, Sr₄PtO₆, and a newly discovered neodymium platinate, Nd_10.67Pt₄O₂₄. Gd₂O₃ did not capture platinum in bench-scale experiments in dry air, but did, however, seem to capture platinum under pilot plant conditions, likely due to the co-capture of Co lost from the N₂O abatement catalyst. The catalytic activity of both oxides and platinum-containing products were studied, toward NO_x and N₂O decomposition. None of the oxides showed significant activity toward NO_x decomposition, and all showed activity toward N₂O decomposition, but to different extents. An overall assessment of the screened oxides with respect to potential use in industrial Ostwald conditions is provided. All tested oxides except CaO and SrO withstood industrial conditions. From our assessments, the nickelates and A₂O₃ (A = Nd, Gd) stand out as superior oxides for platinum capture. Full article

New tetrasubstituted porphyrin tin complexes (5–14) were prepared in two different ways: In the first preparation procedure, tin porphyrin complexes were prepared by a direct reaction of butyltin trichloride and dibutyltin dichloride with tetra/tetrakis(4-X-phenyl)porphyrins (X = H, F, Cl, Br, CF₃, CH₃O, and (CH₃)₂N). In the second procedure, the same tin porphyrin complexes were synthesized from the reaction of butyltin trichloride and dibutyltin dichloride with lithium porphyrinato derivatives. These novel tin complexes were characterized by elemental analysis, ¹H, ¹³C NMR, FTIR, UV-Vis spectroscopy, and mass spectrometry. Among these complexes, tin porphyrin containing methoxy group [Bu₂Sn(TMOPP)] was tested as an adsorbent to remove tetracycline antibiotics from wastewater. The TTC antibiotic removal efficiency (R%) of this complex was measured using UV-Vis spectroscopy. After 120 min of equilibration, the final R% and adsorption capacity (q_t) were measured at 60.15% and 18.10 mg/g, respectively. Full article

A wide range of agro-industrial waste has been generated due to higher demands for food and energy. New protocols for its valorization are urgent strategies for sustainable development. In this work, residual babassu mesocarp, a native plant from the north of Brazil, was used as a matrix for producing lipases through solid-state fermentation (SSF) by actinobacterial strains. Initially, 121 strains were screened by rhodamine B and tributyrin methods, where strain Streptomyces spp. AM9-01 was the most promising. It was submitted to the SSF at 30 °C, where 84.8 ± 1.5 U·mL⁻¹ of hydrolytic activity (HA) was found in 48 h. Further studies at pH 7 increased lipase production, achieving 94.6 ± 1.6 U·mL⁻¹ of HA in 12 h. The enzymatic extract was immobilized in Accurel^® MP1000, where the biocatalyst Lip 10 showed 79.9 ± 1.5% immobilization efficiency, 4234 ± 24 U·g⁻¹ of HA, and activity retention of 55.4%. Lip10 was used to synthesize ethyl oleate, showing conversions of over 97% in 6 h of reaction, while the commercial biocatalysts TLIM^® and N435^® showed conversions of over 95% in just 8 h. In addition, Lip10 showed operational stability for eight consecutive cycles. Therefore, it was demonstrated that babassu mesocarp is a viable alternative for obtaining competitive biocatalysts containing lipases for industrial applications from SSF by actinobacteria, which have few reports in the literature and could be potential biocatalytic agents. Full article

Liquefaction is an effective thermochemical process for converting lignocellulosic biomass into bio-oil, a hydrocarbon-rich resource. This study explores liquefied biomass electrolysis as a novel method to promote the electrocracking of organic molecules into value-added compounds while simultaneously producing hydrogen (H₂). Key innovations include utilizing water from the liquefaction process as an electrolyte component to minimize industrial waste and incorporating carbon dioxide (CO₂) into the process to enhance decarbonization efforts and generate valuable byproducts. The electrolysis process was optimized by adding 2 M KOH, and voltammetric methods were employed to analyze the resulting emulsion. The experimental conditions, such as the temperature, anode material, current type, applied cell voltage, and CO₂ bubbling, were systematically evaluated. Direct current electrolysis at 70 °C using nickel electrodes produced 55 mL of H₂ gas with the highest Faradaic (43%) and energetic (39%) efficiency. On the other hand, pulsed electrolysis at room temperature generated a higher H₂ gas volume (102 mL) but was less efficient, showing 30% Faradaic and 11% energetic efficiency. FTIR analysis revealed no significant functional group changes in the electrolyte post-electrolysis. Additionally, the solid deposits formed at the anode had an ash content of 36%. This work demonstrates that electrocracking bio-oil is a clean, sustainable approach to H₂ production and the synthesis of valuable organic compounds, offering significant potential for biorefinery applications. Full article

Laccase from Trametes versicolor was immobilized via the formation of interlinking enzyme aggregates (CLEA). Its free and immobilized enzymes were characterized, and its efficiency was tested via the removal of bisphenol A (BPA) in aqueous solution. The resistances against thermal denaturation and pH variations were improved upon immobilization. Although the optimal pH of the enzyme was not modified by immobilization, the latter considerably increased its stability in the pH range of 2.0 to 8.0. The immobilized form was still 50% active after 6 months of storage, while the free form took 1 month to suffer a similar drop in activity. Both free and immobilized T. versicolor laccases were efficient in removing 200 µM BPA from aqueous solutions. The free laccase removed 79% and 92.9% of the compound during the first hour of reaction when 0.1 and 0.2 U were used, respectively. The immobilized form, on the other hand, removed 72% and 94.1% of 200 µM BPA during the first hour of reaction when 0.2 and 0.5 U were used, respectively. The immobilized enzyme allowed seven reuse cycles in the oxidation of ABTS and up to four cycles in the degradation of BPA. The results suggest that the laccase from T. versicolor may be useful in biological strategies aiming at degrading endocrine disruptors, such as BPA. Full article

One-component or bifunctional organocatalysts are some of the most capable compounds to perform the synthesis of cyclic carbonates from epoxides and carbon dioxide (CO₂) since the presence of a co-catalyst is not required. In this study, we designed, synthesized, and evaluated five halogenated compounds as bifunctional organocatalysts for this catalytic transformation. Among them, 1,3-dimethylimidazolium iodide (1) exhibited the highest catalytic efficiency, enabling the synthesis of a broad range of monosubstituted cyclic carbonates with diverse functional groups under mild conditions (80 °C, 20 bar CO₂) within 1 h, using only 1 mol% catalyst loading. Remarkably, this organocatalyst also facilitated the synthesis of five internal cyclic carbonates and a carvone-derived exo-cyclic carbonate, which was obtained for the first time without the use of a metal catalyst, under more demanding conditions. A mechanistic proposal was developed through a combination of ¹H-NMR studies and density functional theory (DFT) simulations. Styrene oxide and cyclohexene oxide were used as model substrates to investigate the reaction pathway, which was computed using an optimized climbing-image nudged elastic band (CI-NEB) method. The results revealed the critical role of 1,3-dimethylimidazolium iodide in key reaction steps, particularly in facilitating the epoxy ring opening process. These findings highlight the potential use of bifunctional compounds as efficient and versatile catalysts for CO₂ valorization. Full article