Sustainable Synthesis Research Articles

Sustainable synthesis of indium oxide nanoparticles via Aloe Vera for gas sensing applications

A green synthesis approach was used to produce nanocrystalline indium oxide (In2O3) nanoparticles from the Aloe Vera Barbadensis Miller species. The obtained In2O3 powder was subsequently employed as a functional material to build thick film resistors (TFR) as a sensor on a porous alumina substrate using screen printing method. The TFR samples were sintered at three different temperatures: 600, 700, and 800 °C. A variety of analytical techniques was used to characterize the nanocrystalline In2O3 powder, including Fourier Transform Infrared (FTIR), Ultraviolet–Visible–Near Infrared (UV–Vis–NIR) spectroscopy, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and X-Ray Diffraction (XRD). Additionally, electrical properties and sensor performance were evaluated. The results showed that the electrical resistivity of the thick film sensor created using the green synthesis method was much higher than that of traditional synthesis techniques. The green synthesis of nanocrystalline In2O3 with Aloe Vera not only benefits the environment, but it also improves the material’s sensitivity and function as an ethanol sensor. This investigation demonstrates the promise of green synthesis techniques for creating high-performance sensing materials and devices.

Sustainable synthesis of NaX by quasi-solid phase conversion from coal fly ash

Converting coal fly ash (CFA) into zeolite is an alternative way to reduce the solid waste and produce high value-added products because CFA contains a large amount of Si and Al elements. Here we provide a novel method to synthesize NaX from CFA via a quasi-solid phase (QSP) conversion rather than classical hydrothermal method, in line with the principle of using and discharging as little water as possible. The pretreatment by HCl and NaOH, the effects of some important factors such as molar ratio of H2O to SiO2, seed amount, crystallization temperature and time were investigated to optimize the process. It’s exciting that the NaX with high crystallinity was obtained under optimal conditions when the molar ratio of H2O to SiO2 was only 8. In addition, the water retention performance of NaX in sand was studied, showing a possibility of desertification control using synthesized zeolite from CFA.

Microwave fostered sustainable synthesis of Nb2O5 – ZnO nanomaterial for efficiency amplification in high performing energy systems

This study presents the first report on the microwave approach combined with improved sustainable synthesis of zinc oxide (ZnO) and niobium oxide (Nb2O5) to generate Nb2O5 – ZnO nanospheres. Following the development of nanospheres, the band gap energy decreased to 3.25 eV, and the average crystallite size was found to be 62.49 nm. The nanospheres had a mixed crystalline phase of hexagonal and orthogonal crystals. This material has demonstrated a predisposition towards hydrogen production in the electro-catalytic tests, with a minimal overpotential (ηHER) and a Tafel slope values of 127 mV and 125.6 mV dec-1. Furthermore, nanospheres decorated electrode remained intact in electrolyte environment for 1500 min and exhibited profound charge storage of 204.93 F g-1. 15% PV efficiency was attained by the air-processed perovskite solar cell thanks to the interface passivation functionality. The commendable performance of the binary Nb2O5 – ZnO nanospheres have validated their prospects for practical applications.

Flux-Screened Copper/Electric Dual-Catalyzed Chemo- and Enantioselective Ullmann-Type C-C Coupling Reactions.

This study introduces an innovative copper/electric dual-catalyzed approach to Ullmann coupling reactions. Our research delineates a series of chemoselective cross-couplings among various halogenated aromatics and enantioselective couplings involving halogenated aryl aldehydes. We employed a flux screening technique to refine the reaction parameters, which is rarely reported in the field of electrochemical synthesis. This advancement accelerates the determination of optimal reaction conditions and affords some inspiration for developing sustainable and ecofriendly chemical synthesis.

Sustainable Synthesis of Rare Earth Metal Tungstates (REWO, RE = Ce, SM, Gd) for Electrochemical Detection of 4-Nitrotoluene

Sustainable Synthesis of Rare Earth Metal Tungstates (REWO, RE = Ce, SM, Gd) for Electrochemical Detection of 4-Nitrotoluene

A Sonochemical and Mechanochemical One-Pot Multicomponent/Click Coupling Strategy for the Sustainable Synthesis of Bis-Heterocyclic Drug Scaffolds.

Bis-heterocycles were synthesized via a consecutive one-pot process by a Groebke-Blackburn-Bienaymé reaction (GBB-3CR) followed by Copper-catalyzed Alkyne-Azide Cycloaddition (CuAAC) assisted by alternative sustainable energies (ASE) such as ultrasonic and mechanical. These efficient and convergent strategies allowed the in situ generation of complex azides functionalized with imidazo[1,2-a]pyridines (IMPs), which was used as a synthetic platform. The target molecules contain two privileged scaffolds in medicinal chemistry: IMPs and the heterocyclic bioisostere of trans-amide bond, the 1,4-disubstituted 1H-1,2,3-triazoles (1,4-DS-1,2,3-Ts).

Sustainable synthesis of multifaceted copper oxide nanoparticles from Euphorbia tirucalli: Unveiling antimicrobial and catalytic potential

This work presents Euphorbia tirucalli mediated green synthesis of multi-purpose copper oxide nanoparticles (ET@CuO-NPs) exhibiting enhanced antimicrobial activity. These plant extract capped nanoparticles were characterized using sophisticated techniques such as FTIR, Raman, UV–Vis, SEM, HR-TEM, DLS, zeta potential, XPS and XRD. A uniform rod-shaped morphology was observed in HR-TEM images with size around 50 nm. Antibacterial and antifungal activity was investigated by agar well diffusion method. The bactericidal action was confirmed by zone of inhibition of 28 mm and 34 mm respectively against gram-negative and a gram-positive bacterium. The nanoparticles also show excellent antioxidant activity via free radical scavenging by DPPH. The scope of ET@CuO-NPs was extended to catalytic reduction of nitroaromatic compounds into their corresponding amino derivatives. The reduction of 4-nitrophenol, a model nitroaromatic pollutant could be completed within just 6 min with a recycling efficiency of 8 cycles. Thus, the multifaceted ET@CuO-NPs exhibited diverse therapeutic and catalytic potential.

A Urease-Catalyzed Three-Component Reaction for the Efficient and Sustainable Synthesis of Highly Substituted 4H-Pyrans in Water as the Solvent

AbstractAn efficient urease-catalyzed approach for the synthesis of highly substituted 6-amino-4H-pyran-3-carbonitriles based on the formation of three bonds in one step is developed. This unprecedented three-component reaction between one molecule of an aromatic aldehyde and two molecules of an aroylacetonitrile proceeds by employing commercially available urease from jack bean (Canavalia ensiformis) as the catalyst in water at 65 °C to deliver the desired 4H-pyrans in yields of up to 92%. The transformation is proposed to occur via a domino Knoevenagel condensation/1,4-addition/O-cyclization/tautomerization sequence, providing a practical and sustainable approach to 6-amino-4H-pyran-3-carbonitriles from commercially available substrates. Full and unambiguous structural elucidation of all the products is achieved by means of NMR spectroscopy and X-ray crystal structure analysis.

Study of Fe3O4 and Cu2+ doped modified Fe3O4 nano catalyst for photocatalytic degradation of methylene blue and eriochrome black-T dyes: Synthesis, characterization, and antimicrobial assessment

This study presents the synthesis and characterization of undoped Fe3O4 and 3% Cu-doped Fe3O4 nanoparticles via a cost-effective and environmentally friendly co-precipitation method. A comprehensive suite of nanomaterial characterization techniques, including energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), and X-ray photoelectron spectroscopy (XPS), was employed to confirm the elemental composition, structural parameters, and chemical states of the prepared materials. Additionally, fragmentation analysis using LC–MS illustrated the structural stability and breakdown of the nanoparticles under specific conditions. Both the materials were characterized by vibrating sample magnetometer (VSM), Brunauer-Emmett-Teller (BET) for investigating the magnetic, and surface characteristics respectively. Furthermore, the synthesized nanoparticles were evaluated for their photocatalytic degradation efficiency towards methylene blue and eriochrome black T dyes. A systematic investigation of various parameters, including the pH of the dye solution, dye concentration over time, catalyst dose, dye concentration versus degradation, catalyst reusability, and kinetic study, was conducted to understand the factors influencing the photocatalytic activity of both undoped and Cu-doped Fe3O4 nanoparticles. The LC-MS analysis predicted the probable degradation pathways of MB and EBT dyes. This work provides insights into the sustainable synthesis, comprehensive characterization, and practical application of Fe3O4-based nanoparticles for water treatment applications, highlighting their potential as efficient and environmentally benign Photocatalyst for wastewater remediation. An investigation was conducted to investigate the antimicrobial properties of both undoped and doped nanoparticles. The minimum inhibitory concentration (MIC) of the synthesized nanoparticles were determined against the bacterial strains E. coli, P. aeruginosa, S. aureus, and S. pyogenes, as well as the fungal strains C. albicans, A. niger, and A. clavatus.

P‐Block Metal Based Single‐Atom Catalysts Surpass Transition‐Metal Counterparts in Photocatalytic H2O2 Production

Growing interest in p‐block metal single‐atom catalysts (PM‐SACs) is driven by their low toxicity, economic viability, and transition metal‐like catalytic properties. However, selection criteria for p‐block single‐atom species and catalytic mechanisms of PM‐SACs remain unclear. This study explores the catalytic abilities of PM‐SACs and their transition metal counterparts (TM‐SACs) based on polymetric carbon nitride (PCN) for photocatalytic hydrogen peroxide (H2O2) production. Using thermodynamic barriers as a key descriptor, it was found that PM‐SACs can surpass TM‐SACs in H2O2 production due to a lower energy barrier for *OOH intermediate formation resulting from optimized p‐p hybridization. Specifically, Sb‐SAC based on PCN shows the highest apparent quantum yield of 35.3% at 400 nm. This study offers a rationale for the utilization of p‐block SACs in the context of sustainable chemical synthesis.

Single-Atom Catalysts with p-Block Metals Surpass Transition-Metal Counterparts in the Photocatalytic H2O2 Production.

Growing interest in p-block metal single-atom catalysts (PM-SACs) is driven by their low toxicity, economic viability, and transition metal-like catalytic properties. However, selection criteria for p-block single-atom species and catalytic mechanisms of PM-SACs remain unclear. This study explores the catalytic abilities of PM-SACs and their transition metal counterparts (TM-SACs) based on polymetric carbon nitride (PCN) for photocatalytic hydrogen peroxide (H2O2) production. Using thermodynamic barriers as a key descriptor, it was found that PM-SACs can surpass TM-SACs in H2O2 production due to a lower energy barrier for *OOH intermediate formation resulting from optimized p-p hybridization. Specifically, Sb-SAC based on PCN shows the highest apparent quantum yield of 35.3 % at 400 nm. This study offers a rationale for the utilization of p-block SACs in the context of sustainable chemical synthesis.

From dairy waste to value-added bio-based surfactants

Cheese whey permeate, the main waste stream of dairy industry, was used as a starting material for the production of bio-based surfactants (SFAEs). Specifically, the first step in the sustainable chemoenzymatic synthesis of n-butyl 6-O-palmitoyl-D-glycosides (Fischer glycosylation followed by enzymatic esterification) was optimized by a chemometric study. The surfactancy of the prepared isomeric mixtures was deeply investigated in terms of static and dynamic interfacial tension and emulsifying capability over time.

Solvent-free synthesis of hierarchical tungsten-doped MFI zeolite for cyclohexene epoxidation reaction

Solvent-free synthesis method in zeolite preparation can largely decrease the generation of wastewater and improve the zeolite yield by simply grinding and hydrothermal treatment for the solid raw materials, and accordingly is considered as one of the most promisingly green and sustainable synthesis strategy for the metal-doped zeolite materials. However, there are scarcely any reports on the solvent-free synthesis and catalytic application of tungsten-doped zeolite materials. In this work, tungsten-doped MFI zeolites were prepared with solvent-free synthesis method and used as heterogeneous catalyst for cyclohexene epoxidation reaction. The synthesized tungsten-doped MFI zeolites displayed a monoclinic (P21/n) space group attributed to the successful incorporation of tungsten atom into MFI framework and meanwhile possessed an enormous number of irregular mesopores ranging from 2 nm to 50 nm. The influence of TPAOH addition amount on the mesopore structure and properties of tungsten-doped MFI zeolite was further investigated. In addition, the crystallization process of tungsten-doped MFI zeolite sample was tracked and analyzed with SEM, XRD and BET characterizations, and accordingly possible formation process for hierarchical zeolite was proposed. Furthermore, the prepared hierarchical tungsten-doped MFI zeolite displayed eminent cyclohexene epoxidation performance and re-usability for more than five times. This work provides some guidance for the solvent-free synthesis of metallosilicate zeolites, decreasing the generation of wastewater and improving the zeolite yield.

Synthesis and application of biomass-based graphene oxide using microwave-assisted pyrolysis method

Graphene and related materials have excellent potential to revolutionise many emerging fields, but the large quantity synthesis using environmentally sustainable methods is still challenging. This work studies the synthesis of graphene oxide from food waste biochar with negatively charged properties, which is initially produced using microwave pyrolysis. The synthesised graphene oxide achieved 64.53 % carbon content, 345.79 m2/g surface area, 0.074 cm3/g micropore volume, large reactive surface area, and ribbon/banded organisation. The performance of carbon-based material is evaluated in the fabrication of a modified screen-printed carbon electrode (SPCE) for selective dopamine (DA) detection in the coexistence of ascorbic acid (AA) and uric acid (UA). The electrostatic interactions between the negatively charged biochar-based graphene oxide (BBGO) on the surface SPCE and opposite-charged dopamine assisted the oxidation potential with interfering species by electrostatic repulsion of AA and UA. This manuscript substantiates the resource recovery from organic materials and sustainable graphene oxide synthesis, underscoring their application in detecting positively charged species.

Sustainable synthesis of benzimidazoles catalyzed by recyclable functionalized organosilica

A highly efficient protocol is herein reported for the preparation of benzimidazole compounds from o-phenylenediamine and various benzaldehyde derivatives in the presence of heterogeneous pyridinium protic ionic liquids supported on periodic mesoporous organosilica (PMO) in water. The synthesis of three novel benzimidazole derivatives is also reported. The proposed approach successfully afforded products in good yield under mild reaction conditions. PMO-Py-IL exhibited excellent catalyst activity and reusability for at least ten reaction cycles with no significant activity loss.

Sustainable synthesis of ZnO and FexOy nanoparticles and their nanocomposite ZnFe2O4: Comprehensive characterization and applications in antioxidant activity and antibiotics degradation efficiency

This study focuses on developing and evaluating eco-friendly nanoparticles, specifically FexOy NPs, ZnO NPs, and a ZnFe2O4 nanocomposite (NC), for potential applications in environmental remediation and biomedicine. The nanoparticles were synthesized and characterized using X-ray diffraction (XRD), which revealed their crystalline structures with sizes of 20.3 nm for FexOy NPs, 22.1 nm for ZnO NPs, and 10.9 nm for ZnFe2O4 NC. Fourier-transform infrared (FTIR) spectroscopy identified functional groups, while UV–visible spectroscopy determined band gap energies of 2.35 eV, 3.38 eV, and 2.68 eV for FexOy NPs, ZnO NPs, and ZnFe2O4 NC, respectively. Morphological analysis via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that FexOy NPs have cubic, hexagonal, and tetragonal forms, ZnO NPs are hexagonal nanorods, and ZnFe2O4 NC has a hexagonal-faced cubic structure. Antioxidant activity, assessed through the DPPH assay, revealed that ZnFe2O4 NC had the highest potency. Additionally, under sunlight irradiation, ZnFe2O4 NC demonstrated superior degradation of the antibiotic cephalexin (96 % within 30 min) compared to FexOy NPs (58.2 %) and ZnO NPs (52 %), with respective kinetic rate constants of 0.109 min−1, 0.029 min−1, and 0.025 min−1. These results highlight the nanoparticles’ potential for environmental and biomedical applications.

Application of Fe3O4@MCC Nanoparticles as a Heterogeneous Catalyst for Sustainable Multicomponent Synthesis of 2,3′‐Biindoles

AbstractDeveloping innovative methods for synthesizing unique 2,3'‐biindole derivatives is crucial for the progression of drug and material discovery. The use of transition‐metal‐catalyzed coupling improves the efficiency and structural diversity in the synthesis of biindoles. Among these methods, heterogeneous catalysis, particularly using Fe3O4 nanocatalyst supported by microcrystalline cellulose (MCC), is promising for green chemistry applications. In the present work, sixteen 2,3'‐biindole derivatives (4a‐p) were prepared using Fe3O4@MCC nanocatalyst which demonstrated enhanced performance, cost‐effectiveness, and reusability. The magnetic properties of the catalyst enable easy separation, simplifying purification processes, and enhancing overall reaction efficiency to 78%–93%. This method aligns with sustainable chemical practices and offers practical benefits for various industrial applications. This environment friendly method boasts several advantages and demonstrates excellent green chemistry metrics, including process mass intensity, environmental impact factor, atom economy, and reaction mass efficiency, atom economy, carbon efficiency, chemical yield, and optimum efficiency.

Recent Advances in Ammonia Synthesis Modeling and Experiments on Metal Nitrides and Other Catalytic Surfaces

In this review, we explore the recent progress in catalytic materials for the ammonia syntheses that are based on metal nitrides and other catalytic surfaces. It comprises a detailed overlook of the various techniques used in ammonia synthesis research and the state-of-the-art modeling techniques employed to investigate new reaction mechanisms and more efficient processes for sustainable ammonia synthesis production. The review is discussed in the context of the reaction mechanisms developed and the recent progress that has been made with respect to thermal, electrochemical, and photocatalytic ammonia synthesis.

Continuous Flow Microreactors for the High-efficiency Enzymatic Synthesis of 10-Hydroxystearic Acid from Oleic Acid.

Converting fatty acids into specialty chemicals is sustainable but hindered by the low efficiency and thermal instability of current oleic acid hydratases, along with mass transfer limitations in emulsion reactions. This study introduces an optimized continuous flow micro-reactor (CFMR) that efficiently transforms oleic acid at low (15 g L-1) and high (50 g L-1) concentrations, improving reaction efficiency and overcoming key conversion barriers. The first CFMR model showed reaction speeds surpassing traditional batch stirred tank reactors (BSTR). Optimizations were performed on three key components: liquid storage, mixer, and reaction section of the CFMR, with each round's best conditions carried into the next. This achieved a space-time yield of 597 g L-1 d-1 at a 15 g L-1 oleic acid load. To further enhance the yield, we optimized the emulsifier system to solve incomplete emulsification and developed a two-component feed microreactor (TCFMR) that addressed mass transfer limitations caused by the product at high substrate loads, reaching a 91 % conversion of 50 g L-1 oleic acid in 30 minutes, with a space-time yield of 2312 g L-1 d-1. These advancements represent significant progress in utilizing fatty acids and advancing sustainable chemical synthesis.

Switchable Deep Eutectic Solvents for Sustainable Sulfonamide Synthesis.

A sustainable and scalable protocol for synthesizing variously functionalized sulfonamides, from amines and sulfonyl chlorides, has been developed using environmentally responsible and reusable choline chloride (ChCl)-based deep eutectic solvents (DESs). In ChCl/glycerol (1 : 2 mol mol-1) and ChCl/urea (1 : 2 mol mol-1), these reactions yield up to 97 % under aerobic conditions at ambient temperature within 2-12 h. The practicality of the method is exemplified by the sustainable synthesis of an FFA4 agonist and a key building block en route to anti-Alzheimer drug BMS-299897. A subtle interplay of electronic effects and the solubility characteristics of the starting materials in the aforementioned DESs seem to be responsible for driving the reaction successfully over the hydrolysis of sulfonyl chlorides. The procedure's eco-friendliness is validated by quantitative metrics like the E-factor and the EcoScale, with products isolated by extraction or filtration after decantation.