Search

In this study, a Box–Behnken design was employed to optimize the synthesis of quinoxaline derivatives via the condensation of benzil or furyl with 1,2-diamines using zirconium phosphate (ZrP) as a heterogeneous catalyst and water as a green solvent. The effects of reaction temperature (40–50 °C), catalyst amount (0.02–0.04 g), and stirring time (5–15 min) were investigated. The model exhibited excellent predictive accuracy with an adjusted R2 of 0.997, yielding 97.90% quinoxalines under optimal conditions: 0.03 g catalyst, 12 min reaction time, and 45 °C. Catalyst reusability was confirmed for up to five cycles, with a slight decrease in yield (~ 90% after five uses). Kinetic analysis revealed first-order reaction kinetics with an activation energy of 70.34 kJ/mol. Thermodynamic parameters, including ΔS, ΔH, and ΔG, were calculated using the Eyring-Polanyi equation. A sustainability assessment using green metrics, such as atom economy (AE), reaction mass efficiency (RME), and the E-factor, demonstrated the improved environmental profile of the process. This method offers a greener and efficient approach for quinoxaline synthesis, with potential applications in the pharmaceutical and fine chemical industries. [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 the current study, we have developed an efficient and simple ultrasound-promoted protocol for synthesizing 2-methylthio-3H-1,5-benzodiazepine derivatives from α-oxo ketene dithioacetals using reusable CaFe2O4 nanoparticles as heterogeneous catalysts. The use of CaFe2O4 nanoparticles as catalyst under ultrasonic irradiation gave better yields in shorter reaction times in comparison to our previous synthetic strategy which used basic alumina as a solid support. The nanocatalyst was found to be applicable to diverse aromatic/heteroaromatic and cyclic ketones. In addition, the quantum mechanical calculations (DFT studies) of all the derivatives were carried out using Spartan software to determine the geometry and physiochemical properties of the derivatives and the molecular docking studies of all the optimized derivatives using Autodock Vina and Discovery Studio software to check their efficacy as antifungal agents. Based on the best docking results, In-vitro experimental studies of BDZ-13 and BDZ-19 were carried out to test their efficacy as antifungal agents. [ABSTRACT FROM AUTHOR]

Thiazole is a sulfur and nitrogen-containing five-membered heteroaromatic ring in many FDA-approved drugs and numerous experimental leads. To facilitate access to this structure, several novel methodologies have been developed using easily accessible starting materials and more environmentally friendly protocols. This review focuses on all recently developed methods (2013–2024) that utilized homogeneous or heterogeneous catalyzed methods to synthesize 1,3-thiazole and provides thorough information on the diverse therapeutic applicability of thiazole derivatives in drug discovery and development. Furthermore, this review will ameliorate the understanding of synthetic and medicinal chemists in selecting green and ecological methodologies to synthesize thiazoles judicially. [ABSTRACT FROM AUTHOR]

In this study, an efficient catalytic protocol using CuCoFe2O4@GO (CCF@GO) for the synthesis of amide bond (−CONH−) via direct coupling of carboxylic acids and N,N‐dialkylformamides is presented. The CCF@GO nanocatalyst has been synthesized via a single‐pot solvothermal method, by changing the proportions of copper and cobalt (1:1, 1:3, and 3:1). Catalyst screening, employing a model reaction with benzoic acid and dimethylformamide (DMF), revealed that the 1:1 proportion of CCF@GO catalyst exhibited excellent efficiency, achieving a high conversion (98%) towards amide formation. The enhanced catalytic efficiency observed in CCF@GO catalysts can be ascribed to the uniform distribution of active copper and cobalt species on the graphene oxide support, which possesses a high surface area. Optimization of the reaction was conducted by varying parameters such as temperature, solvent, catalyst loading, and oxidant. The prepared catalyst was characterized using various analytical techniques including XRD, FTIR, XPS, SEM, EDX mapping, and TEM. Furthermore, this heterogeneous nanocatalyst demonstrated recoverability using an external magnet and reused up to five times with just a modest loss of catalytic performance. [ABSTRACT FROM AUTHOR]

Readily available, naturally derived lignin was transformed into a Brønsted acidic organocatalyst. The obtained catalyst was utilized in the environmentally benign synthesis of biologically relevant indole derivatives such as vibrindole, turbomycin, etc. The scope of the developed methodology was further extended for the synthesis of aniline-tethered indoles, 4H-chromene, and indolin-2-one derivatives. Further, vicinal difunctionalization was successfully carried out with the aid of the developed organocatalyst. Imperatively, all the aforementioned reactions were carried out in the aqueous medium. The reusability of the heterogeneous catalyst was also proved by carrying out the reaction with the recovered catalyst. Lignin-based naturally derived Brønsted acidic organocatalyst was utilized in the environmentally benign synthesis of biologically relevant indole derivatives, 4H-chromene, and indolin-2-one derivatives. All the aforementioned transformations were carried out in an environmentally benign aqueous medium. [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]

Study of chitosan modification to MgAl-LDH to increase surface basicity for improving biodiesel production from palm oil has been performed. Modification was conducted by chitosan gel impregnation onto prepared MgAl-LDH. Furthermore, the physicochemical character of material was evaluated by X-ray diffraction (XRD), scanning electron microscope, transmission electron microscope, gas sorption analysis, and determination of solid basicity. The XRD, specific surface area, pore distribution, and TEM analyses confirmed the reduced specific surface area due to the exfoliated LDH conformation. However, the increased surface basicity aroused from the modification leads to improved catalytic activity and yield. The maximum biodiesel yield of 92.8 % was achieved by the methanol to oil ratio of 10:1 at 90 ℃ for 2 h. The prominent reusability until the 5th cycle of usage without significant activity change is a potency for advocating the suitability of the low-cost catalysis technology for commercial biodiesel production. [ABSTRACT FROM AUTHOR]

The commercially available 3,4,9,10‐perylenetetracarboxylic diimide (PTCDI) acted as a heterogeneous catalyst to catalyze aerobic oxidative synthesis of benzimidazoles, benzothiazoles, and quinoxalines from o‐substituted aniline derivatives and primary amines in high yields with oxygen as the terminal oxidant. The gram scale reaction and reusability (up to six cycles) of the PTCDI catalyst were also successful and would greatly benefit industrial applications. [ABSTRACT FROM AUTHOR]

In this present work, a newly designed metal‐oxide nanoparticle incorporated Covalent organic framework (COF), CuxOy@TFP‐ODA has been successfully synthesized and used for the effective synthesis of Oxazolidinones and a‐hydroxy ketones under mild conditions utilizing CO2. Initially, imine‐linked 2D COF, TFP‐ODA was synthesized by simple solvothermal method followed by the embedment of copper oxide nanoparticles (NPs) into the skeleton of the as‐synthesized COF. Different characterization techniques were employed to establish the physical and chemical characteristics of both CuxOy@TFP‐ODA and TFP‐ODA COF materials. To study the catalytic efficiency of the highly porous CuxOy@TFP‐ODA, three components coupling reaction involving primary amine, propargyl alcohol and CO2 to synthesize a series of 2‐Oxazolidinone and synthesis of α‐hydroxy ketones using CO2 as a Co‐catalyst were carried out over the as‐prepared catalyst under green and sustainable conditions which illustrated excellent yields and selectivity of the corresponding products. The synthesized catalyst was proved to be completely heterogeneous and especially, the catalyst material demonstrated significant potential for reuse across several catalytic cycles. [ABSTRACT FROM AUTHOR]

ABSTRACT This study reports the synthesis and application of a polythiophene–iron oxide (PTh‐Fe0‐Fe2O3) nanocomposite as a highly effective catalyst for the selective reduction of nitro aromatics in an aqueous environment. The nanocomposite was synthesized using in situ chemical polymerization, with Fe0‐Fe2O3 nanoparticles created from ferric chloride solution using Camellia sinensis leaf extract as a reducing and stabilizing agent at room temperature. Characterization techniques, including XRD, FTIR, SEM–EDX, TEM, XPS, and UV–Vis spectroscopy, confirmed the successful integration of Fe0‐Fe2O3 into the polythiophene matrix. The nanocomposite demonstrated higher electrical conductivity compared to PTh alone, ranging from 20 S/cm at 313 K to 53 S/cm at 373 K. Magnetic studies indicated a saturation magnetization of 23.1 emu/g, lower than the 42.6 emu/g of Fe0‐Fe2O3 nanoparticles, attributed to the non‐magnetic nature of PTh. Under optimal conditions (4‐nitrobenzaldehyde [1 mmol], catalyst [0.04 g], and water [5 mL] in air), the catalyst achieved a 94% yield in the reduction of nitrobenzenes within 7 h, demonstrating broad applicability and retaining significant catalytic activity over six cycles. Furthermore, the PTh‐ Fe0‐Fe2O3 nanocomposite exhibited notable methanol gas sensing capabilities, with a sensitivity of 52.6 at 200‐ppm methanol. The sensor exhibited a response time of 60 s and a recovery time of 80 s, attributed to its n‐type semiconductor characteristics and abundant oxidative‐reductive sites. Computational studies supported the methanol sensing mechanism, highlighting significant O… S interactions and stable non‐covalent interactions between methanol and the nanocomposite. This study is the first to introduce a novel magnetic nanocatalyst for the cost‐effective and eco‐friendly reduction of nitroarenes, while also demonstrating its applicability in gas sensing. The research highlights an environmentally sustainable synthesis process and enhanced material properties, showcasing the nanocatalyst's potential for diverse applications. [ABSTRACT FROM AUTHOR]

AbstractThis work aims to develop a comprehensive kinetic and simulation study of biodiesel production using waste cooking oil (WCO) catalyzed by blast furnace slag geopolymer (BFSG) as a heterogeneous catalyst. The kinetic investigation was established following the pseudo-first and second-order model using three reaction parameters, namely, the reaction temperature (40–60 °C), reaction time (4–8 h) and catalyst ratio (6–14 wt.%), while maintaining a constant methanol-to-oil composition of 40 wt.%. The geopolymer-catalyzed transesterification process was simulated using ChemCAD version 8.1.0, which incorporates the four major triglycerides (triolein, tripalmitin, tristearin and triolein) of WCO. The results of the transesterification reaction of WCO in a kinetic plug flow reactor (PFR) demonstrated a good fit of the data, with an R2 above 0.96 in both cases. The pseudo-first-order (PFO) model revealed a more favorable reaction pathway, with an activation energy of 58.876 kJ.mol−1, as opposed to the value of 131.369 kJ.mol−1 obtained from the pseudo-second-order (PSO) analysis. The catalytic activity of BFSG yielded a maximum conversion of 99.18% at a 12 wt.% catalyst ratio. The study results demonstrated the effectiveness of the transesterification process catalyzed by BFSG as a promising low-cost technology for the biodiesel industry. [ABSTRACT FROM AUTHOR]

ABSTRACT Concerning the objectives of green chemistry, silica‐coated magnetite nanoparticles provide a new way to implement an efficient and effective system for assisting catalyst recovery across multiple organic reactions. With Fe3O4 spheres serving as the core shell, the synthesis of sulfonic acid‐functionalized silica‐coated magnetic nanoparticles is presented in this paper. FTIR, PXRD, SEM, TEM, EDX, TGA, XPS, and VSM techniques were used to assess the prepared catalyst. The proposed nanocatalyst was employed to produce biological relevance 2‐substituted benzimidazole and bis indole methane derivatives. High yield, quick reaction time, soothing reaction conditions, extended functional group tolerance, and an accessible workup approach are the main advantages of synthesized nanoparticles. Furthermore, the present nanocatalyst may be recovered using an external magnet and retaining its effectiveness for up to six cycles. These are distinctive functions of the present approach. [ABSTRACT FROM AUTHOR]

A heterogeneous zirconium catalyst was grafted on a ceria‐coated silica support, denoted as Zr(OEt)x/CeO2/SiO2. It exhibited higher catalytic activity compared to its homogeneous counterpart, Zr(OEt)4, in the conversion of carbon dioxide to diethyl carbonate using tetraethyl orthosilicate as a regenerable agent in the absence of any dehydrating agents under non‐protic conditions. We found that the ceria‐coated silica (CeO2/SiO2) support not only improved the catalytic activity of Zr(OEt)4 but also inhibited catalyst deactivation during catalyst recycling tests. Furthermore, we analyzed the surface of the Zr(OEt)x/CeO2/SiO2 catalysts by FE‐SEM and EDX. [ABSTRACT FROM AUTHOR]

ABSTRACT Catalyst design and fabrication with safe and affordable components and methods is a high‐value‐added business. In this work, a vitamin‐based hybrid nanomaterial (PMoB1) is prepared by simple stirring of thiamine hydrochloride (vitamin B1, VB1) as an inexpensive commercially available biologically active compound with phosphomolybdic acid (PMo12) in acidic aqueous solution to catalyze selective oxidation of sulfides using aqueous H2O2. A small amount of this heterogeneous catalyst drives rapidly the sulfoxidation reaction under mild and solvent‐free conditions facilitating the product separation and reducing significantly the environmental impacts. The main factors of the catalytic reaction were optimized by the central composite design (CCD) method. The solid catalyst tolerates a wide range of pH and retained its structural integrity even at alkaline solution (pH = 11). PMoB1 composed of two VB1 and one PMo12 was found to be partially reduced based on 13P NMR and UV–Vis spectra. An amorphous structure with aggregated nanoparticles with sizes ranging between 50 and 70 nm and a specific surface area of 35 m2/g are important reasons for enhanced catalytic activity and selectivity. Nevertheless, non‐covalent interactions such as hydrogen bonding and the π–π stacking can also significantly affect the catalyst performance. Given the scavenging tests and spectral evidences, a non‐radical mechanism involving peroxo species is postulated. The catalysis is shown to be truly heterogeneous while the solid catalyst largely maintains its structural integrity during the recycling test. [ABSTRACT FROM AUTHOR]

The catalytic behavior of K/Fe catalyst in biodiesel synthesis by ethanolic transesterification of sunflower vegetable oil was investigated. The catalysts were prepared according to the conventional precipitation, impregnation, and calcination methods. The catalysts were characterized by X-ray diffraction (XRD), FT-IR spectroscopy, thermogravimetric analysis (TGA), and Hammett-Benzoic acid indicator titration. Catalytic tests for biodiesel production revealed an excellent activity of the K/Fe3-800 catalyst, which is consistent with the number of basic sites (1.50 mmol/g) in bulk. Potassium polyferrite phases K1.55Fe11O17/K2Fe10O16 as basic active sites on the catalyst surface were generated, increasing the catalytic ability for biodiesel synthesis. The optimum conditions for transesterification reaction were catalyst amount of 5%, ethanol-to-oil molar ratio of 9:1, reaction temperature of 70 °C, and reaction time of 45 min. The maximum conversion of oil to ethyl esters reached 98.2%. The catalyst can tolerate free fatty acid and moisture up to 0.5% and 1%, respectively. K/Fe3-800 catalyst was successfully reused at least three times without post-treatment, and the obtained yield was higher than 92.3%. The XRD and TGA characterizations showed that poisoning of the active sites and pore fouling are the main reasons for the K/Fe3-800 deactivation. This finding indicates that the potassium loading on iron oxide catalysts provides valuable advantages such as low reaction time, easy recovery, and reuse in the transesterification reaction of sunflower oil. [ABSTRACT FROM AUTHOR]

In this study, a Life Cycle Cost (LCC) is integrated within a life cycle assessment (LCA) model to comprehensively evaluate the energy, environment, and economic impacts of the Jatropha biodiesel production in China. The total energy consumption of producing 1 ton of Jatropha biodiesel is 17566.16 MJ, in which fertilizer utilization and methanol production consume 78.14% and 18.65% of the overall energy consumption, respectively. The production of 1 ton of Jatropha biodiesel emits a number of pollutants, including 1184.52 kg of CO2, 5.86 kg of dust, 5.59 kg of NOx, 2.67 kg of SO2, 2.38 kg of CH4, and 1.05 kg of CO. By calculating and comparing their environmental impacts potentials, it was discovered that NOx and dust emissions during the fertilizer application, combustion of Jatropha shells, and methanol production urgently require improvement, as they contribute to serious global warming and particulate matter formation issues. LCC study shows that the cost of Jatropha biodiesel is 796.32 USD/ton, which is mostly contributed by Jatropha oil cost (44.37% of the total cost) and human input (26.70% of the total cost). Additional profits are generated by the combustion of Jatropha shells and glycerol by-product, which can compensate 16.76% of the cost of Jatropha biodiesel. [ABSTRACT FROM AUTHOR]

Complexes of first row transition metals are a promising class of inexpensive catalysts for oxidation reactions. In this work, we studied the influence of covalent immobilization of Mn-porphyrin onto the surface of activated carbon in the green oxidation of various olefins. meso-tetrakis(4-carboxyphenyl)porphyrinatomanganese(III) acetate (MnTCPP) immobilized onto hydroxylated activated carbon (AC-OH). The anchored catalyst was characterized using FTIR, UV–VIS, atomic absorption and EDX spectroscopies. TGA analysis and BET-BJH method were employed to determine thermal behavior and surface properties of complex respectively. Then, catalytic performance of MnTCPP@AC-OH was investigated in the green oxidation of olefins with molecular oxygen and hydrogen peroxide. A comparison between two green oxidants (molecular oxygen and hydrogen peroxide) shows that although more product is obtained with hydrogen peroxide, more recyclability is obtained with molecular oxygen. The separation and recovery of the nanocatalyst was simple, effective and economical in this green oxidation method and the supported catalyst can be reused at least five times without significant loss of activity. [ABSTRACT FROM AUTHOR]

In this research, microorganisms were used to produce Gd2ZnMnO6 NFs in a biological process instead of a chemical method as a nanocatalyst. Considering the capability of the microorganisms to synthesize nanofibrous (NFs) upon exposure to metal ions, microorganisms were employed to produce Gd2ZnMnO6 NFs through a biological process. The utilization of chemical modification to fabricate environmentally friendly heterogeneous nanocatalysts has proven to be highly appealing in the context of synthesizing 3-aryl-2-oxazolidinones using alkenes, carbon dioxide, and amines in an aqueous solution. The role of diverse variables in the creation of 3-aryl-2-oxazolidinones has been thoroughly investigated. Notably, Gd2ZnMnO6 NFs demonstrates remarkable efficiency in the production of 3-aryl-2-oxazolidinones due to its unique morphology. The morphology of Gd2ZnMnO6 NFs contributed to the creation of a desirable outer layer for the creation of 3-aryl-2-oxazolidinones. The findings demonstrated that the utilization of Gd2ZnMnO6 nanofibers positively impacts the effectiveness of the creation of 3-aryl-2-oxazolidinones. This can be attributed to the nanofibers' impressive mechanical and ionic internal characteristics, as well as their exceptional thermal sustainability and persistent colloidal sturdiness. Consequently, employing the host–guest method, the system could be regarded as an exemplary nanocatalyst. A diverse array of olefins was successfully transformed into desirable products, independent of the electronic nature of the substitutes. The involvement of heterogeneous mixtures did not impede the progression of the reaction. Moreover, the 3-aryl-2-oxazolidinones were easily distinguished from the Gd2ZnMnO6 nanofibers, and the medium exhibited the ability to undergo multiple cycles of usage without experiencing a notable decline in their catalytic activity and selectivity. This approach offers notable advantages, including a strong economic capability and the potential to withstand functional groups. Synthesis of biogenic Gd2ZnMnO6 nanofibrous for creation of 3-Aryl-2-oxazolidinones from alkenes, carbon dioxide, and aminesSynthesis of biogenic Gd2ZnMnO6 nanofibrous for creation of 3-Aryl-2-oxazolidinones from alkenes, carbon dioxide, and amines [ABSTRACT FROM AUTHOR]

In an attempt to expand the utility of natural compounds in catalysis, a novel heterogeneous catalyst derived from Gum Arabic, a natural polysaccharide, was synthesized by its modification with chlorosulfuric acid and subsequent magnetization. Material characterization confirmed the successful modification and magnetization of GA. Hammet method also approved increase of acidity of gum upon functionalization with chlorosulfuric acid. According to Response Surface Methodology optimization, this catalyst exhibited high activity for the conversion of fructose to 5-hydroxymethylfurfural under mild conditions, achieving a 96% yield at 85 °C within 73 min using 30 wt% catalyst loading. The kinetic study indicated an activation energy of 89 kJ/mol. Thermodynamic parameters were determined, with enthalpy, entropy, and Gibbs free energy values of 86.11 kJ/mol, − 29.45 J/mol, and 96.65 kJ/mol, respectively. Furthermore, the catalyst displayed excellent recyclability, retaining over 87% activity for five consecutive cycles, and a heterogenous nature as confirmed by hot filtration test. This study demonstrates the potential of the as-prepared catalyst for sustainable 5-hydroxymethylfurfural production, highlighting its high activity, recyclability, and environmentally friendly nature. [ABSTRACT FROM AUTHOR]

In this work, NiCo2O4 was synthesized from bimetallic oxalate and utilized as a heterogeneous catalyst to active peroxymonosulfate (PMS) for the degradation of tetracycline (TC). The degradation efficiency of TC (30 mg/L) in the NiCo2O4 + PMS system reached 92.4%, with NiCo2O4 exhibiting satisfactory reusability, stability, and applicability. Radical trapping test and electron paramagnetic resonance (EPR) results indicated that SO4•−, •OH, O2•−, and 1O2 were the dominating reactive oxygen species (ROS) for TC degradation in the NiCo2O4 + PMS system. Seven intermediates were identified, and their degradation pathways were proposed. Toxicity assessment using T.E.S.T software (its version is 5.1.1.0) revealed that the identified intermediates had lower toxicity compared to intact TC. A rice seed germination test further confirmed that the NiCo2O4 + PMS system effectively degraded TC into low-toxicity or non-toxic products. In conclusion, NiCo2O4 shows promise as a safe and efficient catalyst in advanced oxidation processes (AOPs) for the degradation of organic pollutants. [ABSTRACT FROM AUTHOR]

Herein, the development of a niobium-based metal–organic framework (Nb-MOF) designed to serve as a catalytic support for the production of hydrogen (H2) from sodium borohydride (NaBH4) is reported. The Nb-MOF was synthesized via a solvothermal method using niobium ammoniacal oxalate (AmOxaNb) as the metal source and 1,4-benzenedicarboxylic acid (BDC) as the ligand. The resulting MOF was characterized by Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The characterization study confirmed the successful synthesis of Nb-MOF. The catalytic activity was optimized by examining five key factors: (i) platinum (Pt) and cobalt (Co) bimetallic compositions (ranging from 1:0 to 0:1 mmol), (ii) NaBH4 concentration (0.2, 0.3, 0.4, and 0.5 mol L−1), (iii) the Nb-MOF/Pt–Co catalyst dose (0.05, 0.10, 0.20, and 0.40 mmol), (iv) sodium hydroxide (NaOH) concentration (0.01, 0.05, 0.1, and 0.2 mol L−1), and (v) system temperature (293.15, 298.15, 303.15, 313.15, and 323.15 K). The optimal catalyst was identified as Nb-MOF supporting a Pt-Co bimetallic composition in a 0.4:0.6 mmol ratio, achieving a hydrogen generation rate (HGR) of 1473 mL min−1 gcat−1 and an activation energy of 19.2 kJ mol−1. Furthermore, this catalyst maintained its efficiency over 20 cycles, demonstrating significant potential as a sustainable solution for H2 evolution from NaBH4. [ABSTRACT FROM AUTHOR]

Amorphous mesoporous materials are promising as catalysts for processes involving or forming bulk molecules. In a reaction such as acetone condensation to form mesitylene, an effective catalyst should not only have a developed porous structure but also have active centers of acidic and basic types. The sol–gel approach allows one to obtain titanosilicates with such characteristics. This work demonstrates the possibility of controlling their properties by varying the conditions for the synthesis of titanosilicate gels. It has been established that controlling hydrolysis allows one to increase the activity of amorphous mesoporous titanosilicates by 10 times: from acetone conversion of 6% to 60%. It has been shown that the use of titanium acetylacetonate complexes in the synthesis of gels leads to an increase in the content of tetracoordinated Ti in the structure and contributes to an increase in the acidity of titanosilicates. During the condensation of acetone on the obtained mesoporous titanosilicates, high acetone conversion (60–79%) and mesitylene selectivity of up to 83% were achieved. [ABSTRACT FROM AUTHOR]

The current study describes the fabrication of nano-catalyst by embedding the magnetic nanoparticles as a core in silica shell to obtain the structure of Fe3O4@SiO2 and then functionalized with sulfonyl groups. The intrinsic properties of nano-catalysts were scrutinized for morphological, crystal structure, elemental and chemical bonding analysis using SEM, XRD, EDS and FT-IR, respectively. The acid density and saturation magnetization were observed to be 0.20 mmol g−1 and 56 emu g−1, respectively. In this study, banana peel waste was pre-treated and hydrolyzed into total reducing the sugar by sulfonated silica magnetic catalyst. A single-factor optimization method has also been used to investigate the influence of catalyst/solid quantity, reaction temperature and time on reducing sugar. The optimum sugar-reducing yield of about 73% was achieved with 0.3% (w/v) of catalyst loading at 140 °C for 2 h. In addition, the spent sulfonated silica catalyst was regenerated and reused up to 3 times. The fermentation by Saccharomyces cerevisiae was conducted with banana peel hydrolysate, and fermentation efficiency reached 83% after 48 h. [ABSTRACT FROM AUTHOR]

Pittosporum resiniferum oil was extracted from the seed and the oil together with methanol was use for the production of biodiesel through transesterification process using novel solid base catalyst (K2CO3 supported on MgO). 0.6:5 (K2CO3 loaded on MgO), a 5 h calcination time, 600°C calcination temperatures were the optimum conditions under which the catalyst was prepared. FTIR, SEM, CO2‐TPD, XRD, N2 adsorption‐desorption, Hammett indicators and other techniques were used to characterize the catalyst. The molar ratio of methanol‐to‐oil, the catalyst amount, time of the reaction as well as the temperature of the reaction were examined. The study found that 16:1 methanol‐to‐oil molar ratio, 5% catalyst loading amount, a reaction time of 2.0 h, and a reaction temperature of 60°C were sufficient for a maximum yield of 97.4%. With relative high activity, the catalyst can perhaps be used again possibly for five times. The characteristics of the biodiesel produced were consistent with international standards. [ABSTRACT FROM AUTHOR]

The new Mn (II) complex of the "salamo" salen ligand of unsymmetrical oxime was synthesized and immobilized on MCM-41 by the multi-grafting method. The immobilized unsymmetrical salamo complex of manganese (MCM-41-Mn salamo) was used as a catalyst in the epoxidation of the alkenes with H2O2. The effect of various reaction parameters which may affect the conversion such as reaction time, temperature, amount of catalyst, oxidant and imidazole was investigated. The prepared Mn catalyst exhibited excellent reusability and could be reused at least five times without significant leaching or loss of activity. [ABSTRACT FROM AUTHOR]

An atom‐economical sequential‐flow synthesis of donepezil, a widely prescribed drug for Alzheimer's disease, was accomplished using inexpensive, commercially available precursors. This achievement was made possible by reconfiguring the synthetic route to include only heterogeneous catalytic addition and condensation reactions, with a particular emphasis on skeletal transformation and bond formation through hydrogenation processes. Notably, water was the sole byproduct in this synthesis. A crucial aspect of this work was the development of appropriate continuous‐flow processes to achieve a one‐flow synthesis. This was accomplished by implementing in‐line treatments of the main reaction stream to eliminate inhibitory factors that could affect catalyst performance in the hydrogenation steps. [ABSTRACT FROM AUTHOR]

The catastrophic ramifications of fossil fuels on the environment have prompted the search for renewable energy sources. Over the recent decades, biodiesel has garnered attention as a promising direct alternative to diesel fuel; however, reliance on homogeneous catalysts and the requirement for refined vegetable oil feedstocks present financial and sustainability concerns. Thus, there exists a need for the development of sustainable and cost‐effective catalytic solutions. Herein, the application of lignin, an abundant and renewable biomass, as an effective heterogeneous catalyst is reported for biodiesel production via the esterification of oleic acid. Lignin is extracted from corn straw using sulfuric acid, which endows sulfonic acid groups (0.85 mmol g−1) to its structure allowing it to act as an acid catalyst without additional post‐treatments. Conversion of oleic oil to biodiesel is achieved at 97% using a 1:3 oleic acid to methanol molar ratio with a 5 wt.% catalyst loading at 90 °C after only 30 min. Moreover, the catalyst exhibits a remarkable turnover frequency of 2.61 min−1 proving its efficiency. These findings demonstrate that heterogeneous catalysts can be prepared from biomass waste offering a significantly cheaper and less intensive synthesis process and allowing for a paradigm shift to non‐edible and waste cooking oils. [ABSTRACT FROM AUTHOR]

The pursuit of sustainable practices through the chemical recycling of polyamide wastes holds significant potential, particularly in enabling the recovery of a range of nitrogen‐containing compounds. Herein, we report a novel strategy to upcycle polyamide wastes to tertiary amines with the assistance of H2 in acetic acid under mild conditions (e.g., 180 °C), which is achieved over anatase TiO2 supported Mo single atoms and Rh nanoparticles. In this protocol, the polyamide is first converted into diacetamide intermediates via acidolysis, which are subsequently hydrogenated into corresponding carboxylic acid monomers and tertiary amines in 100 % selectivity. It is verified that Mo single atoms and Rh nanoparticles work together to activate both amide bonds of the diacetamide intermediate, and synergistically catalyze its hydrodeoxygenation to form tertiary amine, but this catalyst is ineffective for hydrogenation of carboxylic acid. This work presents an effective way to reconstruct various polyamide wastes into tertiary amines and carboxylic acids, which may have promising application potential. [ABSTRACT FROM AUTHOR]

The escalating demand for plastic presents an immense peril to both the environment and humanity. Not only have there been notable advancements in the creation of advanced biodegradable polymers, but there has also been a lack of attention towards tackling the current issue of plastic waste. Processing fuels via plastic waste valorization provides a feasible approach to recycle plastics and mitigating pollution for the improvement of society. This review addresses a comprehensive analysis of various heterogeneous catalysts in the context of plastic pyrolysis to produce fuel, intending to identify an eco-friendly method for recycling garbage. The choice of catalyst has a substantial effect on the disintegration process of waste plastic, dictating the properties of the resulting fuel, encompassing both the amount and the quality. Pyrolysis, an alternative method for addressing the increasing waste disposal issue, is a non-toxic process that does not release hazardous pollutants, in contrast to incineration. The waste plastic serves as a feedstock for pyrolysis process, employing innovative, environmentally friendly catalysts derived from natural and other sources, to generate fuel oil that possesses similar physical characteristics to the diminishing petroleum-based fuels. This critical review analyzes the impact of different heterogeneous catalysts on the process of transforming waste plastic to produce fuel through pyrolysis. Heterogeneous catalysts are crucial to the process of turning discarded plastics into oil, offering significant potential for improving not only economic and environmental conditions but also benefiting both industry and society. [ABSTRACT FROM AUTHOR]

The design and development of bifunctional heterogeneous catalysts via interface engineering are a very promising and necessary strategy for constructing highly efficient water electrolyzers. Nevertheless, it remains a great challenge to devolve active catalyst centers for simultaneous activities of oxygen/hydrogen evolution reactions (OER/HER). Herein, an amorphous FeOOH ultrathin nanosheet is grown over crystalline NiCo2S4/Ni3S2 vertically aligned nanosheets (NS) onto a nickel foam (NF) substrate (denoted as FeOOH/NCS/NS/NF) using facile wet chemical approaches. The developed heterogeneous catalyst exhibits superior bifunctional electrocatalytic activities with the lowest overpotentials of 285 mV (OER) and 226 mV (HER) to realize 50 mA cm–2 in alkaline conditions. Consequently, coupling of amorphous FeOOH and crystalline NiCo2S4/Ni3S2 promotes the surface adsorption of oxygen intermediate species along with water dissociation on catalytic active centers and mass transport with electron transfer at the interface. In the alkaline electrolyzer system, the obtained heterogeneous electrode delivers a substantial overall water splitting performance with a small cell voltage of 1.55 (1.70) V to reach 10 (50) mA cm–2, where FeOOH/NCS/NS/NF is used as an anode and cathode. Thus, the proposed heterogeneous catalyst strategy validates the effective pathway to design a competent electrode for water electrolysis applications. [ABSTRACT FROM AUTHOR]

In this work, we applied commercially available 2-pyridinecarboxylic acid to modify cellulose by simple manipulations, and then anchored low-toxicity metal nickel onto the modified cellulose to prepare the heterogeneous catalyst (CL-AcPy-Ni). The obtained catalyst was characterized by FT-IR, TG-DSC, BET, XRD, SEM-EDS, ICP-OES, XPS, and GPC. The catalytic performance of CL-AcPy-Ni in the Suzuki cross-coupling reaction was investigated using 4-methyl iodobenzene and phenylboronic acid as the model substrates reacting in THF under 120 °C for 24 h. The catalytic ability of CL-AcPy-Ni for various halobenzenes and phenylboronic acid derivatives was also further investigated under optimal conditions and demonstrated good catalytic activity, and a series of diaryls were successfully synthesized. Finally, this green nickel-based catalyst could be reused for five successive cycles by simple centrifugation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Tiangong University is the property of Journal of Tianjin Polytechnic University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Waste oyster shells and waste cooking oil (WCO) were used to develop biodiesel, which may be less expensive than fossil fuels. The effect of %catalyst, reaction temperature, ratio of WCO to methanol, and reaction time were experimentally determined using Taguchi-grey (GRA) multi-response analysis. The percentage biodiesel yield, acid number, and water and sediment content were selected as the multi-response. The results suggest an ideal point of 1.5% catalyst, 60 °C reaction temperature, 1:9 oil-to-methanol ratio, and contact time of 6 h to produce 96% biodiesel yield, 0.48 mg KOH/g acid number, and 0.032 vol% water and sediment content. At a 95% confidence level, the projected GRA was fairly close to the experimental GRA. This demonstrated that the optimal processing parameters found were successful. Waste oyster was revealed to be capable of transesterifying WCO, resulting in higher biodiesel yield, reduced acid number, and less water and silt. [ABSTRACT FROM AUTHOR]

A number of water pollution issues caused by antibiotic effluent must be addressed immediately. The persulfate (PS) method is a sort of advanced oxidation process that has the advantages of a quick reaction time and a high oxidation capacity. However, in order to be used efficiently for wastewater treatment, PS must be activated in water. In this study, PS was directly loaded onto the precursor to produce an oxidant that could destroy organic contaminants in water synergistically with O3. The effects of oxidant production circumstances, oxidant dosage, O3 flow rate, PS dose, and pH value on diclofenac (DCF) degradation efficiency were investigated. The results showed that when the initial concentration of DCF was 100 mg/L, the O3 flow rate was 0.4 m3/h, the pH value was 3, and the oxidant dosage was 1 g/L, the S2O82−/Fe2O3-zeolite/O3 system basically completely degraded DCF within 60 min. The EPR and free radical quenching experiments were used to explore the synergistic degradation of DCF by the S2O82−/Fe2O3-zeolite/O3 system. The three possible degradation pathways of DCF were also proposed based on analysis intermediate products analysis with LC–MS. This study identifies potential DCF breakdown pathways and offers a cost-effective and practical multiphase catalyst for the treatment of organic wastewater. A new sulfur-containing catalyst produces both •OH and SO4•− under the action of ozone for efficient removal of diclofenac. [ABSTRACT FROM AUTHOR]

Abstract The synthesis of efficient organic compounds from simple substrates is both noticeable and important. However, it can be challenging to achieve this target using suitable strategies. To address this issue, pyrazinium chlorochromate (PCC) was used to modify carbonitride nanosheets (CNs) and applied as a heterogeneous catalyst in the oxidation of benzyl alcohols. That can be regarded as innovation in ingenious synthesis of the PCC on the CNs. Then, it was identified by varied techniques such as EDS, FT-IR, XRD, STA and FE-SEM. This process resulted in in-situ synthesis of 1,4-dihydropyridine and 3,4-dihydropyrimidin-2-(1H) one derivatives with excellent yield.

This study investigates the thermal conversion of waste coral and its utilization as a heterogeneous catalyst for biodiesel production from soybean oil. In this work, waste coral is calcined at varied temperatures of 800, 900, and 1000°C, and the effect of the calcination temperature on the physicochemical character of the solid is evaluated through Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and basicity measurement. The results show that the higher temperature facilitates the conversion of CaCO3 of the aragonite and calcite phases in raw waste coral into CaO, achieving a complete conversion at the temperature of 1000°C. Thermal conversion influences the increased surface basicity of the solid, which is associated with the higher activity for biodiesel production. Further studies on the obtained CaO as a catalyst demonstrate the catalyst dosage and the methanol-to-oil ratio as significant factors for fatty acid methyl ester production. The highest yield of 98.7% is achieved after a 3 hours reaction with 8 wt.% catalyst dosage and 9:1 methanol-to-oil ratio. The catalyst exhibits stability with an insignificantly decreased yield until the fifth usage cycle. The optimum conditions and reusability features of the calcined waste coral suggest that waste coral is a favorable CaO catalyst source for biodiesel production.

Empty Fruit Bunch (EFB) resulted from oil palm plantations and mills can be converted into ash through open combustion. The EFB ash then treated by simple calcination and used as a heterogeneous catalyst for biodiesel production. The characteristics of EFB ash were identified based on its elemental composition, porous structure, and active site size. The effectivity of the EFB ash as a catalyst was tested in a transesterification reaction of Refined Bleached Deodorized Palm Oil (RBDPO) with excess methanol (30 %-w) in various catalyst loads (in%-wt). The lab-scale experiments were conducted in a three-neck glass reactor, which was put on the hot plate stirrer at 450 rpm. The EFB ash performed the best as a catalyst by attaining optimal conversion at 65 °C for 1 h with a 16 %-wt of catalyst load. In this condition, most of the standard quality of biodiesel were complied with total glycerol under 0.24% and ester methyl contents up to 98.9 %. The characteristics tests showed that the properties and active side of the EFB ash are excellent after calcination at 600 for 5 h. The recyclability test of EFB ash as a catalyst showed high performance in two repetition cycles, each showing an increase in the yield of biodiesel, which was 92.21 % in cycle 2 and 91.23 % in cycle 3.

Advanced Oxidation Processes (AOP), such as persulfate oxidation is a promising contaminant removal agent for treating wastewater. In this study, Sidoarjo volcanic mud (VM) was applied as heterogeneous catalyst to support the persulfate oxidation process for Congo Red (CR) dye removal. The Sidoarjo volcanic mud is known to have a high iron content, making it a potential catalyst in AOP. This study was conducted under conditions of pH 2, CR 50 mg/L, and catalyst dosage 0.5 g/L and effective reaction volume of 300 mL. This experiment was conducted by comparing three types of catalysts: unmodified volcanic mud (UVM), impregnated volcanic mud (Fe-IVM), and calcined volcanic mud (CVM). The methods were carried out by comparing two methods, namely simultaneous and sequential. The obtained CR removal values for UVM, Fe-IVM, and CVM catalysts were 83.73%, 78.86%, 51.96% for simultaneous and 84.75%, 81.72%, and 87.69% for sequential method. Whereas the UVM catalyst has the highest CR removal value with a lower adsorption value of 16.89%. The production of sulfate radical analyzed by comparing the oxidation process of homogeneous and heterogeneous catalysts. It was shown that the application of VM catalyst as heterogeneous catalyst is very promising for dye removal in wastewater treatment.

AbstractIn this study, CuO@HNTs-SO3H was investigated as a novel eco-friendly heterogeneous solid acid catalyst prepared by straightforward co-precipitation method. Thus, the cost-effective CuO NPs was used to modify halloysite nanotubes initially, which were subsequently further functionalized with sulfonic acid. The prepared catalyst was analyzed by means of FT-IR, XRD, EDX, SEM and TGA methods. Its catalytic activity is investigated in the solvent-free one-pot condensation of various aromatic aldehydes, dimedone, and β-naphthol to produce tetrahydrobenzo[a]xanthen-11-one derivatives. A few benefits of the discovered method are its simple process, quick reaction time, high yields (96%), affordable cost, and the catalyst ability to be reused without losing its activity. [ABSTRACT FROM AUTHOR]

This review is focused on various reports in recent years on catalytic Wittig reactions and Knoevenagel condensation reactions in the presence of heterogeneous catalyst. The one-pot, cost-effective stereoselective catalytic Wittig reaction, is the reaction countering components generated by oxidation of primary alcohols without addition of base. Some reactions were reportedly performed under mild conditions, green and efficient approach providing the corresponding products in good to excellent yields within short times. The catalytic behavior over various catalysts for the Tandem oxidation reactions (TORs) was also summarized in this review. [ABSTRACT FROM AUTHOR]

Hydrogen obtained from natural gas pyrolysis is valuable in transitioning to cleaner energy sources, as it provides a cost-effective and environmentally sound alternative to other processes. Utilizing activated carbon particles as catalysts enhances methane conversion rates and helps reduce pyrolysis temperatures while avoiding the high costs and metal contamination risks associated with metal catalysts. This study presents a model for the decomposition of methane over carbon catalysts using a comprehensive kinetic approach. The model includes heterogeneous surface reactions for methane dissociation and carbon depositions. It also introduces a novel method that utilizes the relationship between pore structure and specific surface area to explain the long-term deactivation process of the particles. The results demonstrate good agreement with various deactivation experiments, showing how methane conversion rates decrease as the specific surface area of the particles decreases during the pyrolysis process. Importantly, the simulations confirm the catalytic role of these particles in the pyrolysis process and how their presence in the reactor fundamentally alters the dynamics of the process compared to an empty reactor. The proposed model takes into account the catalytic effects of activated carbon while addressing the challenges posed by its complex pore structures. The findings offer insights into optimizing catalytic methane pyrolysis, providing a pathway to more efficient hydrogen production while harnessing valuable solid carbon by-products. [Display omitted] • The catalytic role of activated carbon in methane pyrolysis is investigated. • Heterogeneous dissociation of CH4 over the surface is key to modelling the process. • Considering the initial pore structure allows for predicting the catalyst stability. • Accurate rates allow for obtaining good results using realistic site density values. • The model aids the efforts in finding a better activated carbon catalyst. [ABSTRACT FROM AUTHOR]

In the realm of solar energy utilization, there is a growing focus on designing and implementing effective photocatalytic systems, for the conversion of solar energy into valuable chemical fuels. The potential of Covalent Organic Polymers (COPs) as photocatalysts for visible‐light‐driven organic transformation has been widely investigated, positioning them as promising candidates in this field. In the design of COPs, introducing a donor‐acceptor arrangement facilitates the transfer of electrons from the donor to the acceptor, creating a charge transfer complex and leading to enhanced conductivity and improved charge separation. Here we present a novel hydrazone‐linked covalent organic polymer ETBC‐PyHz containing TPE donor and pyridine acceptor. Utilizing this, an efficient method has been developed for an oxidative cross‐coupling reaction involving C−S bond formation. This process involves arylhydrazines and arenethiols, and results in the production of unsymmetrical diaryl sulfides via the formation of aryl and thioarene radicals. This conversion holds significant importance because the byproducts produced during the process are nitrogen and water, making it environmentally benign. [ABSTRACT FROM AUTHOR]

The synthesis of 2,5‐diformylfuran (DFF) through photocatalytic oxidation of 5‐hydroxymethylfurfural (HMF) is an attractive approach. In this manuscript, a photocatalytic selective oxidation strategy for HMF was developed, using Ag/Ag3PO4 as the photocatalyst and O2 as the oxidizing agent. The prepared catalyst was characterized systematically by SEM, XRD, XPS, UV‐Vis, PL spectra, and so on. In contrast to previous photocatalytic oxidation strategies for HMF conversion, this catalytic system could efficiently generate 1O2 without other reactive oxygen species (ROS) under visible light irradiation. DFF would be obtained with about 90 % selectivity. Moreover, the exclusive formation of 1O2 was linked to the more positive conduction band potential (+0.90 eV) of Ag/Ag3PO4, confirmed by an array of characterization techniques. Additionally, the stability of the catalyst was assessed through cyclic testing and analyses including XRD, and XPS. Nonetheless, this catalytic system could potentially serve as a robust platform for various selective oxidation reactions in the future, due to its exclusive presence of 1O2 without the involvement of other ROS. [ABSTRACT FROM AUTHOR]

An optimised synthesis of the metal‐organic framework (MOF) UiO‐66(Ce) is reported using a modulator‐free route, yielding ~5 g of material with high crystallinity and 22 % ligand defect. Two methods are developed for loading gold nanoparticles onto the MOF. The first uses a double‐solvent method to introduce HAuCl4 onto UiO‐66(Ce), followed by reduction under 5 % H2 in N2, while the second is a novel one‐pot method where HAuCl4 is added to the synthesis mixture, forming Au nanoparticles within the pores of the UiO‐66(Ce) during crystallisation. Analysis using powder X‐ray diffraction (PXRD), nitrogen adsorption isotherms, transmission electron microscopy and small‐angle X‐ray scattering (SAXS) reveals that the two‐step double‐solvent method yields gold crystallites on the external surface of the MOF particles that are visible by PXRD. In contrast, the one‐pot method forms smaller gold crystallites, with a distribution of sizes centred on ~4 nm diameter as seen by SAXS, with evidence from PXRD for the smallest particles being present within the MOF structure. The Au‐loaded UiO‐66(Ce) materials are evaluated for the catalytic oxidation of vanillyl alcohol to vanillin at 60 °C. Our findings indicate that incorporating Au nanoparticles via the one‐pot synthesis method, enhances redox activity, achieving 43 % conversion and 90 % selectivity towards vanillin. [ABSTRACT FROM AUTHOR]

Aerobic oxidation of olefins without any co‐reductant and high temperature was studies in the presence of nano and bulky Fe‐porphyrin in a comparative manner. Nano‐particles of Fe‐porphyrin were obtained via ultrasound irradiation. The results show higher catalytic efficiency of nano‐catalyst (turnover number of 1300) with respect to the bulk catalyst (turnover number of 600) in the oxidation of cyclohexene with molecular oxygen at room temperature. [ABSTRACT FROM AUTHOR]

Catalytic transformation of CO2 into value‐added chemical products can provide an appropriate solution for the raising environmental issues. To date, various metal‐organic frameworks (MOFs) with transition metal ions have been explored for CO2 capture and conversion, but alkaline earth metal‐based MOFs are comparatively less studied. Metal ions like Sr(II) having relatively large radius give rise to a high coordination number resulting in higher stability of the MOFs. Moreover, the introduction of N‐rich functional group in organic linker like −NH2, −CONH− and triazole into MOF backbone enhance their CO2 capture and conversion efficiency. Herein, the effect of amine group on the catalytic efficiency of MOFs for CO2 cycloaddition with epoxides under solvent free and ambient conditions are presented. The di‐carboxylates, such as 5‐aminoisophthalate (AmIP) and 5‐bromoisophthalate (BrIP) were utilized to synthesize Sr(II) based MOFs. The Zn(II) MOF was synthesized using tetra‐carboxylate containing amide spacer (OAT) and 4‐amino‐4H‐1,2,4‐triazole (AMT). All three MOFs exhibited porous networks with guest available volume ranging from 15 to 58 %. The catalytic efficiency of the MOFs towards carbon dioxide fixation reaction was explored. The catalytic performances revealed that the presence of amine group in the channels enhances the catalytic efficiency of the MOFs. [ABSTRACT FROM AUTHOR]

SBA-15 and organic ionic liquid were incorporated in a post-grafting technique for generating a bifunctional ionic liquid embedded mesoporous SBA-15. The prepared heterogeneous catalyst was employed for the first time to synthesize N-alkylated indoline-2,3-dione at mild conditions to afford excellent yields in a short reaction time. The synthesized DABCOIL@SBA-15 catalyst was meticulously characterized by various techniques, such as FT-IR, solid-state 13C NMR, solid-state 29Si NMR, small-angle X-ray diffraction (XRD), and N2 adsorption–desorption. Further, the morphological behavior of the catalyst was studied by SEM and TEM. The thermal stability and number of active sites were determined by thermogravimetric analysis (TGA). The Hammett equation was used to analyze the synergetic effect of the catalyst and substituent effects on the N-alkylated products of 5-substituted isatin derivatives, which resulted in a negative slope. This negative slope indicates a positive charge in the transition state. Notably, the DABCOIL@SBA-15 catalyst demonstrated its practicality by being reused for seven cycles with consistently high catalytic activity. [ABSTRACT FROM AUTHOR]

An organic–inorganic hybrid polyoxometalate (POM) CoPMoV [PMoVI8VIV4VV2O42][Co(Phen)2(H2O)]2[TEA]2•H3O•3H2O (Phen = 1,10-phenanthroline, TEA = triethylamine) prepared by hydrothermal synthesis was explored as a heterogeneous catalysts to remove methylene blue (MB) through Fenton-like reaction and catalytic reduction. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) were employed to characterize CoPMoV. The MB removal rates for the Fenton-like reaction and the catalytic reduction were 91.6% (120 min) and 97.5% (2 min), respectively, under optimum conditions. CoPMoV demonstrated excellent stability and recyclability in the Fenton-like reaction and catalytic reduction, which was confirmed by 5 cycle tests. Plausible mechanisms for MB degradation and reduction have also been proposed. Benefiting from the excellent redox properties of cobalt and [PMoVI8VIV4VV2O42]5− anion, CoPMoV could act as a Fenton-like and reductive catalyst for the removal of MB. This study provides a green and facile strategy to design POM-based organic–inorganic material for dye wastewater treatment via oxidation and reduction. [ABSTRACT FROM AUTHOR]