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Contributed to the synergistic effects of multiple active sites such as Lewis acid-base, HBD groups and nucleophilic ion, the external-skeleton B-containing IL modified BBN-Imi-SBA-15-I catalyst exhibited excellent catalytic activity to CO 2 -epoxide coupling reaction under metal- and cocatalyst-free conditions. [Display omitted] A novel external-skeleton B-containing ionic liquid modified SBA-15 catalyst BBN-Imi-SBA-15-I (BBN denotes borabicyclo[3.3.1]nonane, Imi represents imidazolium ionic liquid) was successfully constructed by a post-modification method for efficiently catalyzing CO 2 -epoxide coupling reaction under both metal- and solvent-free conditions. 5BBN-Imi-SBA-15-I (5 refers to the molar ratio of Si to B), thanks to its synergistic effects of Lewis acid, weak base sites from tertiary amine and quaternary ammonium, hydrogen bond group and nucleophilic group, displayed good catalytic activity with 97 % product yield and 99 % selectivity at 100 °C, 2 MPa in the absence of cocatalyst. The obtained catalyst demonstrated good recyclability during six consecutive catalytic runs, also presented generality for various mono-substitute epoxides. Through in-situ NH 3 diffuse reflectance infrared Fourier transform spectroscopy (NH 3 -DRIFTS) characterization, the Lewis acidity of organo-boron was verified. Besides, kinetics research also proved the positive effect of multiple active components on efficient catalysis under milder conditions over SiO 2 -based metal-free catalysts. [ABSTRACT FROM AUTHOR]

The isomerization of n-alkanes through hydrogenation is a crucial process for producing high-quality, clean oil products. The development of high-performance and cost-effective hydroisomerization catalysts is pivotal to this process. In this work, by leveraging the spatial steric effect of SAPO-11, a highly efficient Ni/SAPO-11 catalyst was prepared through a one-step solid-phase synthesis method to enhance isomerization activity. As well as its physicochemical properties, the effects of the aluminum source, template agent, silicon–aluminum ratio, crystallization temperature, crystallization time and nickel–aluminum ratio on the preparation of Ni/SAPO-11 catalyst were investigated. Utilizing pseudo-boehmite, phosphoric acid, silica sol, dipropylamine and nickel nitrate at the molar ratio of 1.0 Al2O3 : 1.0 P2O5 : 0.4 SiO2 : 2.0 DPA : 0.2 NiO under crystallization at 200 °C for 24 h obtained a Ni/SAPO-11 catalyst with suitable acid properties for the isomerization process. Three forms of Ni species were obtained by using a Ni/SAPO-11 catalyst: NiO with hydrogenation ability after reduction, framework nickel with acidic sites, and nickel–aluminum spinels. More importantly, achieving a balance between the dispersion of hydrogenation active sites and suitable acid properties with isomerization active sites was essential for highly effective hydroisomerization. In the hydroisomerization of n-hexane, optimizing the relationship between the catalyst metal sites and acidic sites resulted in a 70.9% conversion of n-hexane with a selectivity for isohexane of 93.0% over the Ni/SAPO-11 catalyst. [ABSTRACT FROM AUTHOR]

The development of high activity, high stability and low cost anode catalysts is a key challenge for the commercialization of direct formic acid fuel cells. The ternary Pd-based alloy catalyst has been proved to be an effective catalyst for formic acid electrooxidation. Herein, PdCoNi ternary alloy catalyst with flower-like ultrathin nanosheet structure are fabricated to serve as a robust electrocatalyst for formic acid oxidation reaction (FAOR) by a simple two-step wet chemical method. Surpassing binary PdCo Ns, PdNi Ns and Pd/C catalysts, the as-prepared PdCoNi Ns achieve extremely high catalytic activity of formic acid oxidation (3221.2 mA·mg−1 Pd), with a mass activity 2.6 times that of PdCo Ns, 2.3 times that of PdNi Ns, and 6.3 times that of Pd/C. After undergoing 1000 cycles of aging tests, the peak current density of PdCoNi Ns catalyst remains at around 65.8%, far superior to Pd/C catalysts, demonstrating substantially improved stability. The improvement of electrocatalytic performance depends on the introduction of Co and Ni atoms, which can effectively modify electronic structure of Pd, increase the available active sites, accelerate charge transfer rate as well as promote mass transport by ultrathin nanosheet structure. Hence, PdCoNi Ns possesses a promising future as a fuel cell electrocatalyst. Combining alloying of ternary metals Pd, Co, Ni and the unique flower-like ultrathin nanosheet morphology controlling, PdCoNi Ns catalyst shows large ECSA, superior electrocatalytic activity, high stability, far surpassing those of binary PdCo Ns, PdNi Ns, Pd Ns and conventional Pd/C catalysts for formic acid electrooxidation. [Display omitted] • PdCoNi with flower-like ultrathin nanosheet structure was prepared for FAOR. • PdCoNi Ns shows excellent mass activity for FAOR, 6.3 times that of Pd/C. • Compared with Pd/C, PdCoNi Ns catalyst exhibits significant advantages in stability. • The synergy between Pd, Co and Ni endouws it with excellent catalytic performance. [ABSTRACT FROM AUTHOR]

The widespread use of biomass in power plants has led to a significant increase in the levels of alkali/alkaline earth metals and phosphorus in the flue gas. This poses a greater challenge to the catalyst. CeMo catalyst is a promising catalyst for NOx removal due to its superior properties. Therefore, this study focused on the single and synergistic effects of Na and P on the CeMo catalysts. Fresh CeMo sample showed the best deNOx performance, with > 90% NOx conversion obtained between 250 and 400 °C. Given the addition of Na or P, catalyst acid and redox features were somehow weakened, which inhibited both the adsorption and activation of the reactants. This behavior resulted in an overall decrease in the catalyst activity of about 5–10%. As Na and P were co-introduced, the NOx conversion efficiency dropped sharply to below 80% within the investigated temperature range. It could be attributed to the fact that the above-mentioned two chemical properties were further negatively affected, which exerted a more pronounced inhibitory effect on the SCR reactions. This work provides insights into the effect of synergistic poisoning on the catalyst properties, laying a solid foundation for the development of new catalysts with excellent resistance ability to multiple poisoning. [ABSTRACT FROM AUTHOR]

In the present study, zeolite H-BEA catalyst has been modified by controlled desilication post modification route using first with cationic surfactant, (6-Bromohexyl)trimethylammonium Bromide (6-Br-TMA) designated as MBB catalyst and then the other with 6-Br-TMA and yeast, designated as MBBY catalyst. These newly synthesized catalytic materials have been characterized by several techniques such as, Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction, scanning electron microscopy, solid state NMR (29Si, 27Al, 1H) N2 sorption isotherm analysis, thermogravimetric analysis, ammonia temperature program desorption (NH3-TPD) analysis, etc. These mesozeolites were found to exhibit enhanced physicochemical (BET surface area, surface acidity, pore volume, mesoporosity, etc.) characteristics as compared to their parent zeolite H-BEA. Catalytic assessement studies of the synthesized zeolites has been demonstrated via conducting experiments involving esterification of levulinic acid (LA) and n-hexanol. Parametric studies has been undertaken in order to get maximum LA conversion by varying several reaction parameters such as molar ratio (acid to n-hexanol), catalyst concentration, reaction time, etc. Further catalysts' reusability studies has been carried out to assess their potential for reusability. The results indicated better catalytic performance of the zeolite H-BEA which is modified with the use of yeast (MBBY) as compared to microporous zeolite H-BEA and MBB catalyst which may be due to its enhanced surface area and surface acidity. [ABSTRACT FROM AUTHOR]

The widespread use of biomass in power plants has led to a significant increase in the levels of alkali/alkaline earth metals and phosphorus in the flue gas. This poses a greater challenge to the catalyst. CeMo catalyst is a promising catalyst for NOx removal due to its superior properties. Therefore, this study focused on the single and synergistic effects of Na and P on the CeMo catalysts. Fresh CeMo sample showed the best deNOx performance, with > 90% NOx conversion obtained between 250 and 400 °C. Given the addition of Na or P, catalyst acid and redox features were somehow weakened, which inhibited both the adsorption and activation of the reactants. This behavior resulted in an overall decrease in the catalyst activity of about 5–10%. As Na and P were co-introduced, the NOx conversion efficiency dropped sharply to below 80% within the investigated temperature range. It could be attributed to the fact that the above-mentioned two chemical properties were further negatively affected, which exerted a more pronounced inhibitory effect on the SCR reactions. This work provides insights into the effect of synergistic poisoning on the catalyst properties, laying a solid foundation for the development of new catalysts with excellent resistance ability to multiple poisoning. [ABSTRACT FROM AUTHOR]

An organocatalyzed Fischer indolization is established by combining 2,2′-biphenol (10 mol%) and B(OH)3 (30 mol%) as weak, readily available, and easy-to-handle acids. The inclusion of MgSO4 , which efficiently scavenges NH3 (a possible acid catalyst poison), appears to be key to the success of this process. The corresponding indoles are obtained in yields of up to 91% using this method.y [ABSTRACT FROM AUTHOR]

Ground-level ozone pollution poses significant risks to ecosystems and human health and requires effective control measures. This study focused on the monolithic ozone degradation catalyst based on powdered α-MnO2 and comprehensively investigated its catalytic performance, moisture resistance, and stability. The monolithic catalyst achieved the optimal catalytic activity with an ozone conversion rate of 99% after being calcined at 400 °C for 3 hours. The detailed characterization of the catalyst properties at pH = 1, 4, and 7 revealed the adverse effects of residual acid ions on the catalyst activity. The catalyst at pH = 7 had more oxygen vacancies, which was related to the reduction of sulfate ion residues and the exposure of more active sites during the washing process. At pH = 7 and a space velocity of 900 000 h−1, the conversion rates of α-MnO2 to 18 ppm ozone reached 100% and 95% within 3 hours under 90% relative humidity and dry conditions, respectively. In addition, the monolithic catalyst exhibited significant moisture resistance and performed well in continuous alternating humidity cycle tests and sustained high humidity. It still maintained 90% ozone decomposition efficiency after 3 hours of testing under high humidity conditions. Meanwhile, the α-MnO2 monolithic catalyst showed excellent stability, with an ozone conversion rate exceeding 99% during the 50 – hour test period. These findings highlight the great potential of the α-MnO2 monolithic catalyst in ozone removal applications. [ABSTRACT FROM AUTHOR]

In this study, in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy was used to analyze the surface reactivity during the dehydration of tetrahydrofurfuryl alcohol (THFA) to 3,4-dihydro-2H-pyran (DHP). The dehydration reaction of THFA is carried out in the gas phase at 648 K using activated γ-Al2O3 as catalyst. Under these conditions, a yield of 84% DHP is obtained in a fixed-bed reactor and the catalyst shows no signs of deactivation after 70 h. The information obtained with DRIFT in situ spectroscopy depends on the reaction conditions, with the concentration of THFA in the gas phase being a critical variable. The temperature and time on stream have also been studied. This technique has allowed to identify DHP, the product of interest, two products with carbonyl group (C = O) formed in the surface of the catalyst during the reaction, and also the formation of carboxylates from the reaction of surface species with the oxygens of the oxide catalyst. This is of considerable significance, as an understanding of the molecular processes occurring at the surface during the reaction would permit the rational design of catalysts to enhance their catalytic properties. Therefore, in situ DRIFT spectroscopy is a valuable tool for studying active catalysts in the THFA dehydration reaction. [ABSTRACT FROM AUTHOR]

Several sepiolite-based catalysts have been prepared and investigated for pyrolytic H2 production from a post-consumer mixture of residual plastics. The experimental installation involved a two-stage reaction system: first, the plastic mixture was thermally pyrolyzed at 500 ºC; then, the generated volatiles were reformed by increasing the temperature to 700 ºC and 800 ºC in the presence of the sepiolite-based catalysts. The real mixture came from non-separate waste collection streams and contained post-consumer polypropylene (rigid and film), expanded polystyrene, high-impact polystyrene, and polyethylene. The results demonstrated that the two-stage pyrolysis technique using sepiolite-based catalysts successfully generated hydrogen. The effects of the type of polymer, temperature, and catalyst were analyzed. The higher production of hydrogen (27.2 mmol H2/g) was obtained when the mixture of plastic waste was pyrolyzed and then the volatiles were reformed at 800 °C with the SN5-800 12 nickel-modified sepiolite. Additionally, the generation of hydrogen also increased after acidifying natural sepiolite (from 18.2 mmol H2/g plastic for natural sepiolite to 26.4 mmol H2/g for acidified sepiolite at 800 ºC with a plastic/catalyst ratio of 1:2). Finally, the carbon deposited in the catalysts was examined. Approximately, only 20% of the carbon that was deposited in the sepiolite-based catalysts was filamentous carbon; the majority was amorphous carbon. The results have therefore shown that it is possible to obtain a hydrogen-rich gas from the reforming of the pyrolysis vapors of a mixture of plastic waste using a low-cost catalyst based on nickel-modified sepiolite. [ABSTRACT FROM AUTHOR]

Hydrogenation of levulinic acid (LA) represents a significant approach for producing the high-value biomass-based platform compound γ-valerolactone (GVL). In this study, an efficient RuIr alloy bimetallic catalyst supported on SiC was synthesized and applied for the aqueous hydrogenation of LA into GVL under mild conditions. The RuIr/SiC catalyst exhibited high LA conversion and GVL selectivity (both > 99%) in water at 0.2 MPa H2 pressure and 25 °C. The excellent performance is attributed to the synergistic interaction between Ru and Ir nanoparticles on the semiconducting SiC support. Furthermore, the catalytic activity of the RuIr/SiC alloy remained basically unchanged after five cycles, confirming the high stability of the bimetallic alloy catalyst. [ABSTRACT FROM AUTHOR]

Ruthenium-based catalysts were prepared through a deposition–precipitation approach, taking beta zeolites with Si/Al ratios of 12.5, 18.5, and 150, respectively, as supports, and 1–3 wt% loadings of metal. Their activation was performed in the presence of either H2 or NaBH4. The dispersion of the Ru species and the acid–base properties were influenced by both the preparation method and the activation protocol. The catalysts reduced under H2 flow presented well-dispersed Ru(0) and RuOx nanoparticles, while the reduction with NaBH4 led to larger RuOx crystallites and highly dispersed Ru(0). These characteristics exerted an important role in the hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL). The H2 dissociation occurred via a heterolytic mechanism involving Lewis acid–base pairs associated with RuOx and the framework oxygen (Si-O-Al) located near the zeolite pore edge. The Ru(0) nanoparticles activated the –C=O bond of the LA substrate, while the presence of the carrier zeolite Brønsted acid sites promoted the ring-closure esterification of the 4-hydroxyvaleric acid (4-HVA) intermediate to GVL. An optimal combination of these features was achieved for the catalyst with 3 wt% Ru and a Si/Al ratio of 150, which selectively converted LA (XLA = 96.5%) to GVL (SGVL = 97.8%) at 130 °C and 10 bars of H2. [ABSTRACT FROM AUTHOR]

Acidic CO2 electrolysis offers a promising strategy to achieve high carbon utilization and high energy efficiency. However, challenges still remain in suppressing the competitive hydrogen evolution reaction (HER) and improving product selectivity. Although high concentrations of potassium ions (K+) can suppress HER and accelerate CO2 reduction, they still inevitably suffer from salt precipitation problems. In this study, we demonstrate that the sulfonate‐based polyelectrolyte, polystyrene sulfonate (PSS), enables to reconstruct the electrode‐electrolyte interface to significantly enhance the acidic CO2 electrolysis. Mechanistic studies reveal that PSS induces high local K+ concentrations through the electrostatic interaction between PSS anions and K+. In situ spectroscopy reveals that PSS reshapes the interfacial hydrogen–bond (H‐bond) network, which is attributed to the H‐bonds between PSS anions and hydrated proton, as well as the steric hindrance of the additive molecules. This greatly weakens proton transfer kinetics and leads to the suppression of undesirable HER. As a result, a Faradaic efficiency of 93.9 % for CO can be achieved at 250 mA cm−2, simultaneous with a high single‐pass carbon efficiency of 72.2 % on commercial Ag catalysts in acid. This study highlights the important role of the electrode‐electrolyte interface induced by polyelectrolyte additives in promoting electrocatalytic reactions. [ABSTRACT FROM AUTHOR]

The popularity of boron-based catalysis has increased significantly in the field of organic synthesis over the last few decades. As a prominent group of Lewis acid catalysts, halogenated triarylboranes are a potential hydro alkylation catalyst. This research has proposed an effective method for tris (pentafluorophenyl) borane-catalyzed hydroalkylation of different styrenes with various 1, 3 diketones to generate the corresponding alkylated pentane diones in good to exceptional isolated yields. In the current study, we describe polyethylene glycol (PEG) as an effective solvent for the hydroalkylation of C-C bond formation, catalyzed by tris(pentafluorophenyl)borane (TFPB). We have observed that the catalyst is easily and efficiently recycled during this transition. [ABSTRACT FROM AUTHOR]

To expand the applications of hydrophobic silica aerogels derived from rice husk ash (HSA) through simple traditional methods (without adding special materials or processes), this paper employs machine learning to establish mathematical models to identify optimal conditions for extracting water glass and investigates how preparation conditions and heat treatment temperatures affect properties such as the porosity and hydrophobicity of HSA. The results indicate that the decision tree regression model provides the most accurate predictions for the extraction rate and modulus of water glass. Notably, the water contact angle of HSA produced using nitric acid as a catalyst can reach as high as 159.5°, classifying it as a superhydrophobic material. Additionally, while moderately increasing the concentration of the hydrophobic modifier enhances HSA's hydrophobicity, it concurrently reduces its porosity. The HSA maintained hydrophobicity until 500 °C. The pore structure of HSA collapsed gradually with the increase in heat temperature. After treatment at 700 °C, HSA lost its hydrophobicity and the porous structure was severely damaged. Compared with silica aerogel using traditional silicon sources, the damage to pore structure and the crystallization occurred at lower temperatures, but the hydrophobicity remained at higher temperatures. [ABSTRACT FROM AUTHOR]

In the quest for eco‐friendly optics, high refractive index polymers (HRIPs) with degradability have been one of the desirable optical materials for realizing eco‐friendly and efficient lighting technologies. However, it has been challenging for HRIPs to simultaneously realize thermostability, high refractive index (RI), visible transparency, and efficient degradability, all of which are essential for their practical use. In this context, we herein focus on aromatic poly(dithioacetal)s, composed of visible‐transparent yet degradable dithioacetal moieties and rigid phenylene sulfide spacers, exhibiting moderately high Tg (> 60 °C), high RI (> 1.7), and colorless film features. In addition, poly(dithioacetal)s can balance (1) high stability under the operating conditions even upon heating and (2) quantitative degradability that can selectively yield cyclic low‐molecular‐weight products that can be further repolymerized upon further addition of an acid catalyst. These results provide a key concept for high refractive index polymers that allow on‐demand degradability and recyclability without compromising their high potential thermal and optical properties. [ABSTRACT FROM AUTHOR]

The direct synthesis of 1,2‐pentanediol (1,2‐PeD) from renewable xylose and its derivatives derived from hemicellulose is appealing yet challenging due to its low selectivity for the target product. In this study, one‐pot catalytic conversion of xylose to 1,2‐PeD was performed by using nitrogen‐doped carbon (NC) supported Pt catalysts with the assistance of organic acids. A remarkable yield of 49.3 % for 1,2‐PeD was achieved by reacting 0.1869 g xylose in 30 mL water at 200 °C under a hydrogen pressure of 3 MPa for 8 h in the presence of 0.1 g of 2.5Pt/NC600 catalyst and 0.1869 g propanoic acid co‐catalyst. The presence of vicinal Pt‐acid pair sites on the surface of the 2.5Pt/NC600 catalyst exhibited a synergistic effect in promoting the hydrogenation of furfural (FF) to furfuryl alcohol (FFA) intermediate and subsequent hydrogenation and ring‐opening reactions leading to the formation of 1,2‐PeD. The addition of organic acids, may serve as both acid catalyst for dehydration of xylose and hydrogen donor for hydrogenation of FF and FFA, thereby promoting the one‐pot conversion of xylose to 1,2‐PeD. Remarkably, the 2.5Pt/NC600 catalyst demonstrated outstanding catalytic performance and good reusability over five consecutive cycles without significant deactivation. [ABSTRACT FROM AUTHOR]

BACKGROUND: Ethyl lactate produced via esterification between lactic acid and ethanol can be used in plastics, polymers and food industries and renowned for its biodegradability and low toxicity. However, lactic acid self‐catalyzed esterification presents a slow reaction process, and acid catalysts are needed to improve the catalysis. Homogeneous acid catalysts like H2SO4 are corrosive, as well as being difficult to be seperated from the reaction media; therefore, advanced heterogeneous catalysts are more ideal. In this study, two kinds of heteropolyacid–zeolite catalysts, involving loading silicotungstic acid and phosphotungstic acid onto Y zeolite, were synthesized, characterized using X‐ray diffraction, NH3 temperature‐programmed desorption and scanning electron microscopy and analyzed for their catalytic efficiency in the catalytic esterfication. RESULTS: Results showed that the Keggin structures of heteropolyacids were retained during the preparation process and strong acid sites of Y zeolite were enriched, which made the main contribution to the esterification of lactic acid and ethanol. Furthermore, the initial‐stage reaction rate of esterification was significantly enhanced. During the first hour of esterification, the conversion of lactic acid increased from 18% to 65%. Exp Dec1 index model was employed to determine the activation energies of 60HSiW‐Y and 60HPW‐Y, which exhibit values of 29.3 and 28.2 kJ mol−1, respectively. CONCLUSION: This study indicates that Keggin structures of heteropolyacids play a key role in the esterification and heteropolyacid–zeolite catalysts can effectively catalyze the esterification. Meanwhile, the results of the kinetic experiments can be of reference significance for large‐scale industrial processes involving esterification. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

A new transition-metal-free catalytic system which uses sodium iodide as the catalyst with formic acid as the hydrogen donor in a biphasic medium was reported for the reduction of the hydroxyl group and various unsaturated groups such as C＝C, C≡C, C＝N and C＝O. Using the same catalytic system, reductive N-formylation of nitroarenes with formic acid was explored to produce the corresponding amide in high selectivity. Moreover, the catalyst stability was evaluated and reaction mechanisms were studied and proposed for the three model reactions. [ABSTRACT FROM AUTHOR]

We report sulfonated hypercrosslinked polymers (SHCPs) as heterogeneous catalysts for the selective esterification of hexanoic acid with benzyl alcohol. The SHCPs demonstrate tuneable catalytic activity and selectivity, outperforming conventional acid catalysts. We also explore detrimental structural changes over multiple cycles, providing insights for optimising long-term catalyst performance. [ABSTRACT FROM AUTHOR]

Exploring the transformation of carbohydrates into valuable chemicals offers a promising and eco‐friendly method for utilizing renewable biomass resources. Developing a bi‐functional, sustainable heterogeneous catalyst is of utmost importance to attain a high level of selectivity for the desired product, 2,5‐diformylfuran (DFF), in this direct conversion process. In this study, we developed a highly effective catalytic system to convert diverse carbohydrates into DFF. Our approach involved utilizing a MoS2 catalyst supported by amorphous carbon derived from sulfonated sugarcane biomass. The MoS2@SBG‐SO3H composite was successfully synthesized using a facile and highly efficient method. The transformation of fructose into DFF achieved a significant yield of 70 % for 5 h at 160 °C using a one‐step and one‐pot reaction through dehydration and oxidation with oxygen. The oxidation of 5‐hydroxymethylfurfural (HMF) into DFF using MoS2@SBG‐SO3H was obtained at 94 % DFF within 5 h; the activation energy was 38.3 kJ. mol−1. The catalyst displayed convenient recovery and reusability. The direct synthesis of DFF from various carbohydrates, such as sucrose, glucose, maltose, and lactose, resulted in favorable yields. Our research provides a quick, green, and efficient process for preparing carbon‐based solid acid catalysts and DFF. [ABSTRACT FROM AUTHOR]

A new method for the O -methylation of cinnamic acid employing DMSO as the methylating agent has been devised, employing a Ni-DMAP complex as catalyst along with Ag2 O and dimethylamine as additives. This protocol demonstrates broad substrate compatibility and good tolerance towards various functional groups. The key advantages of this approach include the utilization of cost-effective catalysts, moderate to high yield of the products, and short reaction time. [ABSTRACT FROM AUTHOR]

The synthesis of biologically active benzoxanthene, and bis(3-hydroxy-5,5'-dimethyl-2-cyclohexene-1-ones) derivatives has been conducted under an environmentally benign method by using an efficient catalyst, silica-tungstosulphonic acid. The benefits of this catalyst include being safe for the environment, low-cost, and simple to construct. It produces good yields and high purity in a short time and facilitates easy cleansing, products are obtained by straightforward recrystallization without the need for column chromatography. The reagent retained its catalytic activity for at least five consecutive cycles of reuse. The catalyst is described by IR, XRD, and SEM-EDX, which clearly shows that sulfonation happens in silica tungstic acid. In addition, the targeted derivatives were studied for anti-oxidant properties such as DPPH, reducing power assay, and H2O2 scavenging activity. The synthesized products such as 3e, 5k, 5 m, 5o, and 5p showed good anti-oxidant properties. Among all of these compounds, 5p showed good activity due to the nitro substitution on the benzene ring. [ABSTRACT FROM AUTHOR]

Porous silicon is one of the most explored nanostructured materials in various biomedical applications owing to its remarkable properties. However, its inherent chemical instability mandates a robust surface modification procedure, and proper surface bioengineering is essential to ensure its effectiveness in the biomedical field. In this study, we introduce a one‐pot functionalization strategy that simultaneously stabilizes porous silicon nanoparticles and decorates their surface with carbohydrates through hydrosilylation chemistry, combining mild temperatures and a Lewis acid catalyst. This approach yielded a surface functionalization degree of 300 μmol g−1 in just 4 hours at 60 °C, significantly reducing both the prolonged reaction times and high temperatures typically associated with conventional hydrosilylation. Furthermore, this advancement opens the way for utilizing thermolabile molecules useful for surface bioengineering. [ABSTRACT FROM AUTHOR]

The syntheses of novel spirobenzazepinoindole derivatives has been achieved through a highly efficient and synthetic route. The approach involves a two‐step reaction, utilizing indole derivatives, 2‐amino benzyl alcohol, and ninhydrin as key starting materials under mild reaction conditions. The reaction proceeds via a sequential cascade process involving cyclization, condensation and spiro‐annulation, leading to the formation of the spirobenzazepinoindole core structure in good to excellent yields. The method offers broad substrate scope, high atom economy, and operational simplicity. The synthesized spirobenzazepinoindoles were fully characterized by spectroscopic techniques, including NMR (1H & 13C), IR and mass spectrometry. The methodology provides a valuable tool for the rapid generation of structurally complex spirobenzazepinoindoles, which could serve as scaffolds for the development of new therapeutic agents. [ABSTRACT FROM AUTHOR]

Objective: Birch bark contains extractives of lupane series, that have pharmacological activity and are of interest for obtaining new medicines. The predominant component of the birch outer bark extracts is pentacyclic triterpene alcohol, betulin. Allobetulin (19,28-epoxyoleanan-3-ol), a pentacyclic oleanane-type triterpenoid, is an isomer of betulin. Allobetulin and its derivatives are nontoxic compounds having antiviral, antimicrobial, and antitumor activities. Methods: The composition of the allobetulin sample after recrystallization from isopropanol was confirmed by elemental analysis, and its structure, by IR and 1H NMR spectroscopy. The antioxidant properties of allobetulin were tested in vivo and in vitro. Results and Discussion: In the present study, a new one-step method was developed for producing allobetulin directly from birch outer bark by combining the stages of betulin extraction with ethanol and isomerization into allobetulin in the presence of an orthophosphoric acid catalyst. The effect of the duration of the birch outer bark treatment with ethanol and of the H3PO4 content on the allobetulin yield was evaluated. The highest yield of crude allobetulin, 35% of the weight of absolutely dry bark (a.d.b.), was achieved at a process duration of 8 h in the presence of 5% H3PO4 and also at a process duration of 15 h in the presence of 3% H3PO4. Conclusions: The yield of recrystallized allobetulin was ~22% of the weight of a.d.b. [ABSTRACT FROM AUTHOR]

We herein report the fabrication strategy of a robust catalyst for the formic acid electro-oxidation reaction (FAOR) via combining the advantages of a TiO2-related support and the synergistic effects of NiPtCo alloy. With the predominant dehydrogenation pathway, the NiPtCo/Ti0.7W0.3O2 catalyst shows remarkable FAOR mass activity and specific activity of 0.45 A mgMetal−1 and 1.25 mA cm−2, being 3.75- and 4.81-time higher than those of the commercially available Pt/C, respectively. The as-made FAOR electrocatalyst shows superior CO-tolerance and electrocatalytic stability during long-term operation conditions due to the synergistic contributions of each component in the overall catalyst system. [ABSTRACT FROM AUTHOR]

In this work, a novel strategy for the straightforward synthesis of isoxazolo[5,4‐b]pyridines from a one‐pot reaction of aryl glyoxal, 5‐aminoisoxazoles, and malononitrile under ultrasound (US) irradiation is described. In the reaction, acetic acid has a dual role as solvent and catalyst. The advantages of this reaction include easy purification of products, raw materials with easy access, short reaction time, high efficiency, and green conditions by utilizing ultrasound irradiation as an energy source and using acetic acid as solvent and Lewis acid. The synthesis achieved high yields of isoxazolo[5,4‐b]pyridines with a broad substrate scope, successfully producing twelve diverse derivatives. The methodology capitalizes on the benefits of sonochemistry, which accelerates reaction rates and improves selectivity while minimizing waste. The proposed mechanism involves a series of reactions including Knoevenagel condensation, Michael addition, and subsequent cyclization processes. This approach not only streamlines the synthesis of complex heterocycles but also aligns with environmentally friendly practices. [ABSTRACT FROM AUTHOR]

In this study, we present an efficient radical approach for the enantioselective Minisci‐type alkylation of N‐heteroarenes, using chiral phosphoric acid (CPA) as a catalyst under mild conditions, without the need for metals, photocatalysts, and other additives. Prochiral α‐aminoalkyl radicals generated from RAEs were successfully introduced to N‐heteroarene derivatives, including pyridine, quinoline, and isoquinoline, resulting in a range of valuable chiral alkylated N‐heteroarenes with secondary amines in high yields and good to excellent enantioselectivities (up to 98 % ee). The chiral phosphoric acid catalyst not only activates the substrate and induces asymmetry but also facilitates essential electron transfer processes. [ABSTRACT FROM AUTHOR]

The high value‐added utilization of the fluorinated silica slag (FSS) waste, an associated by‐product of the anhydrous HF production from the accompanying fluorine resources in phosphate ore, is of great importance, but it remains a challenge. In this work, the Mg modified and unmodified Hβ zeolites from FSS waste were successfully prepared by a green dry gel conversion crystallization method with tetraethylammonium hydroxide (TEAOH) as a structure‐directing agent (SDA). The in situ Mg modified Hβ zeolite (Mg−Hβ) shows much superior catalytic performance to unmodified (Hβ) and post Mg‐modified Hβ (Mg/Hβ) zeolites for acetylation of 2‐methoxynaphthalene (2‐MN) to 6‐acetyl‐2‐methoxynaphthalene (2,6‐AcMN), and the 40.2 % of conversion for 2‐MN with 66.3 % of selectivity for 2,6‐AcMN were achieved, ascribed to the high amount of B acidic sites and the promoted shape‐selective catalysis effect by higher surface area and volume of micropores. This work not only opens a new avenue for the high value‐added utilization of fluorinated silica slag waste, but also generates an efficient solid acid catalyst for the clean production of 2,6‐AcMN through the acetylation of 2‐MN with acetic anhydride. [ABSTRACT FROM AUTHOR]

Imidazo[1,2-a] pyridines are privileged heterocycles with diverse applications in medicinal chemistry; however, the catalytic asymmetric synthesis of these heterocyclic structures remains underexplored. Herein, we present an efficient and modular approach for the atroposelective synthesis of axially chiral imidazo[1,2-a] pyridines via an asymmetric multicomponent reaction. By utilizing a chiral phosphoric acid catalyst, the Groebke-Blackburn-Bienaymé reaction involving various 6-aryl-2-aminopyridines, aldehydes, and isocyanides gave access to a wide range of imidazo[1,2-a] pyridine atropoisomers with high to excellent yields and enantioselectivities. Extensive control experiments underscored the pivotal role of the remote hydrogen bonding donor on the substrates in achieving high stereoselectivity for these reactions. The versatile derivatizations of these atropisomeric products, especially their role as an analog of NOBINs and their facile conversion into unique 6,6-spirocyclic products, further emphasize the merits of this methodology. [ABSTRACT FROM AUTHOR]

This work presents a novel and eco-friendly technique for the first time to create α-MoO3 nanobelts (NBs) by employing a straightforward procedure with glycerol and ascorbic acid acting as green complexing and polymerizing agents, respectively. The produced α-MoO3 NBs were characterized using a range of analytical techniques, including thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The NBs were used as a catalyst in the manufacturing of biodiesel. To assess the acidity strength of the catalyst, NH3 was used in a temperature-programmed desorption (NH3-TPD) experiment. Biodiesel was effectively produced from oleic acid and ethyl alcohol by the α-MoO3 NBs. Response surface methodology (RSM) was employed in the experimental design and optimization to get the ideal circumstances. Important variables, including temperature, reaction time, catalyst dosage, reaction time, temperature, and the molar ratio of alcohol to fatty acid, were examined. The outcomes demonstrated that the biodiesel production might approach 85% at ideal temperatures of 75 °C, 50 min of reaction time, a 30:1 molar ratio of alcohol to oleic acid, and 0.007 g of catalyst. The results also showed no appreciable activity loss throughout the catalyst's efficient recovery and reuse for four cycles. [ABSTRACT FROM AUTHOR]

(Trifluoromethyl)sulfanylamides are an important class of organic compounds that are common among natural products and drug molecules. Here, we report a (trifluoromethyl)sulfanylation reaction using silver(I) (trifluoromethyl)sulfide as a free-radical (trifluoromethyl)sulfanylation reagent for β-amide compounds. This reaction does not require stoichiometric oxidants or additional transition-metal catalysts, and can be achieved by adding common organic acids. This method has excellent applicability and can accommodate several functional groups, including ester groups, acyl groups, and even bromo or iodo groups. Heterocyclic α,β-amides can also be readily converted into the corresponding products. This reaction also provides a new method for the synthesis of deuterated (trifluoromethyl)sulfanylamides. [ABSTRACT FROM AUTHOR]

Biomass platform compound 5-Hydroxymethylfurfural (HMF), with its low price and abundant source, can be used as a renewable resource to replace traditional petrochemicals. MOF-808(Zr) has tunable active sites and excellent stability under high temperatures and acidic as well as basic environments, and the unsaturated coordination of metal ions within its framework structure can exhibit Lewis acidity, facilitating catalytic transfer hydrogenation from HMF to 2, 5-Furandimethanol (BHMF). The hydrothermal–impregnation–reduction method was used to prepare Cu/MOF-808 catalysts with high catalytic performance. Formic acid was chosen as the hydrogen donor solvent. The selectivity and yield of BHMF were 75.65% and 71%, respectively, at 150 °C for 4 h. A reaction pathway for the catalytic hydrogen transfer of HMF to BHMF was proposed. The high activity and stability of the Cu/MOF-808 catalyst with dual active sites provide a viable method for feasible hydrogenation of HMF to high value-added compounds. [ABSTRACT FROM AUTHOR]

The use of activated carbon-based catalysts for the production of solketal and γ-valerolactone (GVL), two products of interest for biorefinery processes, was investigated. Activated carbons (ACs) were prepared by chemical activation of olive stones, an agricultural byproduct, using H3PO4 to olive stone mass impregnation ratios (IRs) of 1:1 and 3:1, and under nitrogen or air atmosphere. The ACs showed SBET values of 1130–1515 m2/g, owing to the presence of micropores (0.45–0.60 cm3/g). The use of an IR of 3:1 delivered a wider pore size distribution, with mesopore volume increasing up to 1.36 cm3/g. XPS confirmed the presence of phosphorus groups with surface concentrations of 2.2–3.2 wt% strongly bonded the AC surface through C-O-P bonds. The ACs were tested as acid catalysts for the acetalization of glycerol in a stirred batch reactor at temperatures of 30–50 °C, glycerol concentrations of 1.5 to 3.4 mol/L, and 1–3 wt% catalytic loading. The catalytic activity was clearly correlated with the quantity of C-O-P acid groups determined by TPD, which increased when ACs were prepared under air atmosphere. The AC prepared with IR 3:1 under air achieved full selectivity to solketal, with activation energy of 49 kJ/mol and conversion of up to 70%, matching the equilibrium conversion value under the optimum reaction conditions. A bifunctional catalyst was prepared over this AC by deposition of 5 wt% zirconium and tested in stirred batch reactor for the hydrogenation of levulinic acid (LA) using isopropyl alcohol (IPA) as solvent and H2 donor, with LA:IPA ratios from 1:1 to 1:7 and temperatures between 160–200 °C. The catalyst reached full LA conversion and a GVL yield higher than 80% after only 12 h at 200 °C. A test conducted in the presence of water revealed that it was an inhibitor of the reaction. The identification of isopropyl levulinate as an intermediate suggests that the most likely reaction pathway was dehydration, followed by hydrogenation and cyclization, to obtain GVL. Kinetic modelling of the results showed a value of 42 kJ/mol for the hydrogenation step. The reusability of the catalyst was tested for five consecutive reaction cycles, maintaining most of the activity and selectivity towards GVL. [ABSTRACT FROM AUTHOR]

Esterification of levulinic acid with ethanol was investigated using deep eutectic systems based on choline chloride and oxalic or p-toluenesulfonic acid as catalysts under conventional heating and alternative energy inputs, namely microwave, ultrasound, and mechanochemical treatment. The experiments were performed under varying operating conditions such as catalyst type and loading, alcohol to carboxylic acid molar ratio, temperature, or time. The obtained results demonstrate the overall better catalytic performance of the p-toluenesulfonic acid-based deep eutectic mixture in comparison with the oxalic acid-based analogue. The best results: levulinic acid conversion of 76% and 58%, for p-toluenesulfonic and oxalic acid containing deep eutectic systems, respectively, with 100% selectivity for both cases, were achieved for microwave-assisted synthesis with 5 wt.% of catalyst and excess alcohol to acid (molar ratio 5), at 413.15 K and for 10 min. The main advantage of all of the alternative activation methods studied (microwaves, ultrasounds, and ball mill processing) was the significant reduction in the reaction time. [ABSTRACT FROM AUTHOR]

A novel set chalcones 3a-d was efficiently synthesized in elevated produces across the condensing process of Claisen-Schmidt. An eco-friendly and efficient process was designed for creating a novel desired products 5a-f and 7a-f, respectively with excellent yields. This synthesis was accomplished by reacting acetophenone derivatives 1a-d, heteroaromatic aldehydes 2a,b and aminobenzoimidazole 4 or 3-aminopyrazole 6a,b, using acetic acid as both the catalyst and solvent. Solvent optimization was performed during the synthesis of the desired compounds 5a or 7a, highlighting the benefits of using acetic acid that is harmless for the environment, which offers easy procedure, rapid reaction, elevated efficiency and broad tolerance of starting materials. The preferred products were verified through compatible spectroscopic data. The antimicrobial efficacious for all compounds was successfully evaluated against various microorganisms, revealing that 3b exhibited significant antimicrobial activity across all tested microbes, with measurements of the minimum inhibitory concentrations being between 4.80 to 63.8 μM. [ABSTRACT FROM AUTHOR]

Ferrocene and its oxidized counterpart, the ferrocenium cation, represent a fascinating class of organometallic compounds with broad utility across various fields, including organic synthesis, pharmaceuticals, and materials science. Over the years, ferrocene, ferrocenium cations, and their derivatives have also gained prominence for their versatility in catalytic processes. This review article offers an overview of the research of the last decade into ferrocene- and ferrocenium-based catalysis. Key developments are highlighted in catalytic oxidation, cross-coupling, polymerization reactions, and redox-switchable catalysis, as well as the application of ferrocenium cations as Lewis acid catalysts. [ABSTRACT FROM AUTHOR]

A highly stereoselective Brønsted‐acid catalyzed synthesis of densely substituted spiroisoindolinones from enamides and 3‐hydroxy‐isoindolinones is described. With simple Brønsted‐acids, such as para‐toluene sulfonic acid, spiroisoindolinones with three contiguous stereogenic centers are formed in high yields (up to 97 %) and diastereoselectivities (up to >98 : <2 : 0 : 0 dr) under mild reaction conditions. With the use of a chiral phosphoric acid catalyst, a diastereo‐ and enantioselective synthesis of the corresponding spiroisoindolinones was achieved. Mechanistic investigations indicate a step‐wise mechanism via an initial addition of the enamide to an electrophilic N‐acylimine species followed by an intramolecular aza‐Friedel‐Crafts reaction. Addition of a strong Lewis acid can be used to facilitate the second step for less reactive substrates. [ABSTRACT FROM AUTHOR]

Lanthanides were tested (Ce3+, Er3+, and Yb3+) as catalysts to produce lactic acid (LA) from the monosaccharides present in corn stover (glucose, xylose, and arabinose) resulting in ytterbium being the most active. A MW-heated system led to similar LA yield as a conventionally heated pressurized system. The maximum value of LA yield was 40% at 240 °C after 20 min of isothermal treatment regardless the starting monosaccharides, which allowed to propose a similar LA production route based on the products profile determined along time for the three monosaccharides. Temperature and time determined the product profile, observing furfural degradation at severity factors higher than 3.5, while values higher than 5.5 were needed to observe LA degradation. By increasing temperature, catalyst solubility decreased, increasing its presence in the solid residue after treatment. Xylan conversion to LA was similar as for xylose, but lower yield was obtained from microcrystalline cellulose. Corn stover presented more amorphous regions leading to higher hydrolysis yields of its cellulose fraction. [ABSTRACT FROM AUTHOR]

Heterogeneous acid catalysis provides a sustainable and cost-effective replacement to homogeneous catalysts, as it is easily accessible and reusable. In this research, biodiesel was synthesized from palm fatty acid distillate (PFAD) by way of esterification utilizing a heterogeneous acid catalyst composed of CuO/WPLAHC-S, which was derived from waste palm leaves-based hydrochar. The catalyst was characterized using TGA, XRD, FESEM, EDX, BET, FT-IR, Raman, and acid density. The synthesized catalyst was found to have remarkable stability during the thermal test. The BET surface area, pore volume, and pore width of the synthesized catalyst were measured at 118.47 m2/g, 0.05 cm3/g, and 8.15 nm, respectively. The significant acidity density (18.57 mmol/g) facilitated the simultaneous esterification process. The investigation found that the copper-doped activated hydrochar, treated with sulfuric acid, exhibited excellent catalytic activity. A high yield of 98.34% fatty acid methyl ester (FAME) was achieved under mild conditions with the use of a catalyst concentration of 2 wt.%, a methanol-to-PFAD molar ratio of 15:1, and a reaction temperature of 80 °C for a duration of 3 h. For statistical analysis, one-way ANOVA was applied to verify the experimental data set for PFAD esterification optimization parameters by predetermining a 95% confidence interval. All of the esterification parameters met the expectation of a p-value less than 0.05 indicating its significant impact on FAME production. The catalyst exhibited excellent performance by maintaining a FAME yield of over 90% after four reaction cycles without requiring reactivation. The study demonstrates the efficacy of CuO/WPLAHC-S as a promising acid catalyst derived from waste palm leaves-based hydrochar for biodiesel production from PFAD. [ABSTRACT FROM AUTHOR]

In this study, solid acid magnetic nanoparticles Fe3O4@SiO2-S-Bu-SO3H were prepared under appropriate conditions and characterized by various analytical techniques including FT-IR, XRD, FE-SEM, EDX, and VSM. Finally, the catalytic activity of the synthesized Fe3O4@SiO2-S-Bu-SO3H MNPs was investigated for the synthesis of valuable benzothiazole derivatives by the condensation reaction of ortho-aminothiophenol and various aldehydes under ultrasonic conditions. In the presence of the inexpensive, environment-friendly, magnetically recoverable solid acid catalyst, the benzothiazoles were obtained as pure target products in excellent yields (90–98%) and short reaction times (3–11 min). The synthesized Fe3O4@SiO2-S-Bu-SO3H MNPs show great catalytic activity because of the combined effect of Brønsted acidity and high functional group density. This solid acid magnetic nanocatalyst is reusable for several cycles and can be easily segregated from the reaction mixture. In this research, we have successfully developed ultrasonic assisted a green and efficient methodology for the synthesis of the 2-substituted benzothiazole derivatives using MNPs Fe3O4@SiO2-S-Bu-SO3H as a low-cost, environment-friendly, and reusable catalyst with excellent yields and very short reaction times. [ABSTRACT FROM AUTHOR]

Reductive amination is a practical method for converting carbonyl compounds to amines. Using this reaction as an example, we introduce a comprehensive organic chemistry experiment designed for senior undergraduates: the reductive amination of isophthalaldehyde with silane to synthesize m-xylylenediamine. In this reaction, tert-butyl carbamate (BocNH2) serves as the nitrogen source, and triethylsilane (Et3SiH) acts as the reducing agent, with trifluoroacetic acid as the catalyst. Isophthalaldehyde undergoes reductive amination to produce Bocprotected m-xylylenediamine, which is subsequently deprotected to yield m-xylylenediamine hydrochloride. The final product, m-xylylenediamine, is obtained by treating the hydrochloride salt with sodium hydroxide. The experimental procedure includes techniques such as extraction, vacuum distillation, drying, recrystallization, and melting point determination, along with analytical methods like thin-layer chromatography (TLC), infrared (IR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. This synthetic route is well-suited for laboratory synthesis, providing high yields and easy purification of the product. The experiment enhances students' skills in organic synthesis and deepens their understanding and application of spectroscopic techniques. [ABSTRACT FROM AUTHOR]

SO42−/TiO2‐H3Ti5NbOl4 solid acid catalyst was prepared via high‐temperature calcination, proton exchange, pillaring, and impregnation processes. The structures and anchoring model can be confirmed by XRD, SEM, and FT‐IR. The acidic properties and specific surface area were characterized by NH3‐TPD and N2 adsorption‐desorption isotherms. The thermal stability was measured by TG‐DTG. The catalytic performances were evaluated via the esterification reaction of acetic acid and n‐butanol. The results show that SO42−/TiO2‐H3Ti5NbOl4 has stronger acid strength and higher acid content than H3Ti5NbOl4 and TiO2‐H3Ti5NbOl4. The esterification rate of ST‐HTN can be reached at 73.82%. The optimal esterification scheme is as follows: the catalyst dosage is 5 wt%, the molar ratio of alcohol to acid is 1.8:1, the reaction temperature is 127 °C, and reaction time is 5.5 h. Based on the structure‐activity relationship, the esterification properties of the selected catalysts were rationalized, which provided a useful perspective for the development and application of a new generation of esterification catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Glycerine pitch waste used to produce efficient heterogeneous acid catalyst. • A single-step synthesis of glycerol-based carbon catalysts. • High acid site density achieved in both SGC and SGPC. • Excellent oleic acid conversion of 92% in biodiesel production by SGPC. • SGPC performs well despite impurities in glycerine pitch. Glycerine pitch is a highly alkaline residue from the oleochemical industry that contains glycerol and contaminants, such as water, soap, salt and ash. In this study, acidic heterogeneous glycerol-based carbon catalysts were synthesised for biodiesel production via single-step partial carbonisation and sulfonation using pure glycerol and glycerine pitch, producing products labelled as SGC and SGPC, respectively. Carbon materials were obtained by heating glycerol and concentrated sulfuric acid (1:3) at 200℃ for 1 h. The produced SGC and SGPC displayed high densities of sulfonic group (–SO 3 H), i.e. 1.49 and 1.00 mmol·g−1, respectively, alongside carboxylic (–COOH) and phenolic (–OH) acid. In the catalytic evaluation, excellent oleic acid conversions of 96.0 ± 0.4 % and 92.4 ± 0.5 % were achieved using SGC and SGPC, respectively, under optimised reaction conditions: 1:10 M ratio of oleic acid to methanol, 5 % (w/w) catalyst, 64℃ and 5 h. SGPC was found to be recyclable with 68.5 % conversion after the 6th cycle, which was attributed to the loss of –SO 3 H and catalyst deactivation by the deposition of oleic acid on its surface. Remarkably, despite the impurities present in the glycerine pitch, the obtained results demonstrated that the reactivity of SGPC is comparable to SGC and superior to that of commercial solid acid catalysts, which demonstrated that the presence of impurities appears to have minimal impact on the production of carbon materials and their properties. [ABSTRACT FROM AUTHOR]

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Agro-industries produce over 2 billion tons of agricultural waste annually, including by-products like bagasse, molasses, seeds, stems, leaves, straw, and shells. The use of agro-industrial waste is a way to reduce the impact of industrial processes on the environment. The pea pod is a biomass with a high concentration of cellulose, hemicellulose and some lignin; therefore, it can be used to produce platform chemicals by means of a hydrothermal process. There is limited research on the hydrolysis of pea biomass, but it has been shown to obtain high yields. This study analyzed the effectiveness and selectivity of the hydrothermal process using pea pod biomass with a particle size of 0.5 mm at 180 °C for one hour. A 500 mL reactor was used, with a biomass-to-acid solution ratio of 1:20. The concentration of the acid solution was 0.02 M. The concentrations of sugar, formic acid, levulinic acid, HMF, and furfural produced were measured. Among the catalysts studied, adipic acid catalysis showed the highest yield of 65.16%, with 37.09% of sugar, 16.37% of formic acid, and 11.71% of levulinic acid. On the other hand, the catalysts with chloroacetic acid, butyric acid, anthranilic acid, and phthalic acid were less effective but demonstrated selectivity for sugar production, proving that the liquid phase obtained using the catalyst with those acids can be used as carbon sources for a fermentation process. In general, when comparing the process with or without the use of a catalyst, it is observed that with a catalyst in the reaction, the amount of HMF and furfural produced is reduced and the selectivity with respect to sugar production is increased. [ABSTRACT FROM AUTHOR]

The main goal of this work is to evaluate the ability of sulfonated carbon nanoparticles (SCNs) to induce photothermal catalysis of the biodiesel synthesis reaction (transesterification of natural triglycerides (TGs) with alcohols). Carbon nanoparticles (CNs) are produced by the carbonization of cross-linked resin nanoparticles (RNs). The RNs are produced by condensation of a phenol (resorcinol or natural tannin) with formaldehyde under ammonia catalysis (Stober method). The method produces nanoparticles, which are carbonized into carbon nanoparticles (CNs). The illumination of CNs increases the temperature proportionally (linear) to the nanoparticle concentration and exposure time (with saturation). Solid acid catalysts are made by heating in concentrated sulfuric acid (SEAr sulfonation). The application of either light or a catalyst (SCNs) (at 25 °C) induced low conversions (<10%) for the esterification reaction of acetic acid with bioethanol. In contrast, the illumination of the reaction medium containing SCNs induced high conversions (>75%). In the case of biodiesel synthesis (transesterification of sunflower oil with bioethanol), conversions greater than 40% were observed only when light and the catalyst (SCNs) were applied simultaneously. Therefore, it is possible to use sulfonated carbon nanoparticles as photothermally activated catalysts for Fischer esterification and triglyceride transesterification (biodiesel synthesis). [ABSTRACT FROM AUTHOR]

Waste plastics were successfully decomposed with a solid acid catalyst to make oil. Spent FCC (Fluid Catalytic Cracking) catalyst was used for this process. The operation of this process was conducted in a horizontal agitated laboratory reactor with an inner volume of 1 L with 0.1 kg/h to the capacity of 80 kg/h of the demonstrate plant conducted by continuously feeding a plastic flake or molded cube to the heated powder catalyst bed at around 400–450 °C. The yield of oil was as high as 70 to 85%, depending on the type of plastic. The processing of a variety of waste plastics from home waste, industrial waste and even marine plastics could be processed to obtain oil with a low freezing point and a high heating value. The product was mainly composed of iso-paraffins, olefins and aromatics. The effective in situ dichlorination was attained from the waste plastic containing PVC. A small amount of PET in the plastic was converted to methyl benzene during the cracking operation. [ABSTRACT FROM AUTHOR]

The valorization of coffee cherry waste through hydrothermal carbonization (HTC) was investigated using various organic and inorganic acid catalysts to produce platform chemicals. This study aimed to evaluate the effectiveness of these catalysts for enhancing reaction rates, improving yields, and promoting selectivity. The results showed that sulfuric acid and adipic acid were the most effective, each resulting in a 20% increase in the total yield, demonstrating the potential of organic acids as efficient catalysts in HTC. Other catalysts, such as benzoic acid and phenylacetic acid, also showed promising results, while butyric acid significantly decreased the total yield. The most abundantly produced platform chemicals were sugars, followed by formic acid, levulinic acid, HMF, and furfural. These findings highlight the potential of coffee cherry waste as a valuable resource for producing key chemicals, and the feasibility of hydrothermal carbonization as a sustainable approach for biomass valorization. This study emphasizes the importance of selecting the appropriate catalysts to optimize the conversion process and maximize the extraction of valuable chemicals. The environmental and economic implications of these findings are significant, as they can contribute to the development of sustainable and efficient biomass utilization technologies that could transform agricultural waste into high-value products while reducing waste and promoting a circular economy. [ABSTRACT FROM AUTHOR]