Green Chemical Synthesis Research Articles

Cyanobacterial hydrothermal carbonization carbon as photocatalyst for selective aerobic oxidation of cyclohexane

The exploration of catalyst preparation techniques that incorporate environmental-friendly methodologies has consistently been the focus of scientific inquiry within the field of green synthesis of oxygen-containing organic chemicals. Herein, a metal-free hydrothermal carbonation carbon (HTCC) has been prepared utilizing cyanobacterial biomass produced during a water bloom in a freshwater lake. The HTCC produced is capable of performing photocatalytic selective oxidation of cyclohexane to cyclohexanol and cyclohexanone (KA oil) under ambient conditions. The use of cyanobacterial biomass allows for the efficient preparation of HTCC, which exhibits a conversion rate of cyclohexane that is 4.1 times of HTCC prepared with alternative carbon sources (glucose). The selectivity to KA oil over the samples are almost 100%. Characterizations and analysis reveal that cyanobacteria can lead to self-doping of nitrogen and hydrophobicity of the resulting HTCC, while sulfuric acid etching endow it with more photoactive sp2 hybridized structure units that contribute to a higher photogenerated carrier separation efficiency. The suitable band structure enables the cyanobacterial HTCC to produce superoxide radicals to oxidize cyclohexane. These findings are of great significance for the development of eco-friendly photocatalysts and the utilization of biomass resources.

Visible Light-Driven Metal- and Photocatalyst-Free Synthesis of β-Trifluoromethylated Enamines via Trifluoromethyl Thianthrenium Salts.

A novel protocol for the visible-light-driven synthesis of β-trifluoromethylated enamines has been developed, which operates without the use of transition metals or any photocatalysts, utilizing trifluoromethylthiosulfonium salts as the source of trifluoromethyl groups under mild conditions. According to this new protocol, more than 40 products have been prepared in moderate to good yields. In addition to eliminating the need for expensive or toxic transition metals and photocatalysts, this new methodology proves its potential scalability through air-stability, the use of safe and readily available reagents, a two-step one-pot procedure, and effective gram-scale reactions. This innovative approach not only demonstrates promise for green chemical synthesis but also offers a new pathway for the advancement of fluorine chemistry in sustainable organic synthesis.

Bi2Te3/Carbon Nanotube Hybrid Nanomaterials as Catalysts for Thermoelectric Hydrogen Peroxide Generation

Harnessing waste heat from environmental or industrial sources presents a promising approach to eco-friendly and sustainable chemical synthesis. In this study, we introduce a thermoelectrocatalytic (TECatal) system capable of utilizing even small amounts of heat for hydrogen peroxide (H2O2) production. We developed a nanohybrid structure, combining carbon nanotubes (CNTs) and Bi2Te3 nanoflakes (Bi2Te3/CNTs), through a one-pot synthesis method. Bi2Te3, as a thermoelectric (TE) material, generates charge carriers under a temperature gradient via the Seebeck effect, enabling them to participate in surface redox reactions. However, the rapid recombination of these charge carriers greatly limits the TECatal activity. In the Bi2Te3/CNTs nanohybrid system, the introduction of CNTs substantially enhances the efficiency of H2O2 production, as the strong bonding between CNTs and Bi2Te3, along with the excellent conductivity of CNTs, facilitates charge carrier separation and transport, as confirmed by TE electrochemical tests. This study underscores the significant potential of thermoelectric nanomaterials for converting waste heat into green chemical synthesis.

Green Chemistry in Pharmaceutical Synthesis: Sustainable Strategies for Drug Production

The world is shifting from traditional synthetic or chemical technologies towards greener methods due to increasing concerns about maintaining a clean and sustainable environment. The development of eco-friendly products through processes that support environmental sustainability is referred to as a "green approach." In the pharmaceutical industry, there is growing attention to green synthesis of chemicals and materials, both in research and applied science, because green chemistry eliminates harmful processes and materials while promoting innovation in drug and therapeutic agent development. Green chemistry encompasses chemical reactions that minimize environmental impact and reduce toxicity. This field is rapidly evolving within pharmaceutical synthesis, focusing on the creation of sustainable medicines. This review explores the principles and practical applications of this innovative strategy within the pharmaceutical sector. By using environmentally friendly chemical processes, green chemistry reduces hazardous materials and pollution. Its aim is to mitigate the environmental footprint of drug production without compromising the quality and effectiveness of medicines. The approach also emphasizes the use of renewable and sustainable resources, such as shifting from petrochemical-based to bio-based feedstocks, allowing pharmaceutical companies to reduce their greenhouse gas emissions

Green Chemical Synthesis of Cube‐Shaped CuFe2O4 Nanoparticles for Use as Magnetically Retrievable Catalysts in A3 Coupling Reactions

ABSTRACTA3 coupling reaction is a multicomponent reaction (MCR) involving aryl aldehydes, phenyl acetylenes and amines to synthesize a variety of biologically active propargylamine derivatives. Herein, we report the preparation of cube‐shaped CuFe2O4 nanoparticles (NPs) via the hydrothermal method in the presence of Lantana camara flower (LCF) extract to use them as catalysts to synthesize propargylamine derivatives. X‐ray diffraction study confirms the formation of CuFe2O4 NPs with cubic spinel structures. In the presence of LCF extract, cube‐shaped CuFe2O4 NPs are formed predominantly irrespective of the type of alkali used as the hydrolyzing agent. However, a mixture of nearly spherical and cube‐shaped particles has been formed in the absence of additives. The synthesized CuFe2O4 NPs exhibit superparamagnetic behaviour and are magnetically ordered. The synthesized cube‐shaped CuFe2O4 NPs exhibit excellent catalytic activity in the A3 coupling reaction between benzaldehyde, piperidine and phenylacetylene to give propargylamine with a yield of 90% under the optimum conditions. The catalyst is highly stable and magnetically retrievable facilitating reusability for up to five cycles without considerable loss of catalytic activity. The protocol is suitable for the synthesis of a diverse range of propargylamine derivatives with moderate to excellent yield.

Graphene oxide dispersed rose-petals based green chemistry synthesis of hybrid composite for novel spectroscopic applications

Rosa Santana family includes the rose, a highly prized decorative plant having symbolic, cultural, and commercial value. The exploration of graphene-based nanocomposites has expanded significantly, with recent research focusing on integrating these materials into natural and sustainable matrices. This study investigates the dispersion of graphene oxide (GO) within the biological structure of rose-petals, representing a novel approach to developing eco-friendly nanocomposites. The rich colours of the roses are ascribed to pigments such as flavanols, carotenoids, and anthocyanin. Carotenoids, which are found in natural colours including yellow, orange, violet, as well as another ingredient found in rose petals. By leveraging the inherent properties of rose petals, such as their unique properties and surface morphology and biocompatibility, this work highlights the potential of GO to enhance the mechanical, electrical, and optical characteristics of the composite. Advanced characterization techniques, including scanning electron microscopy (SEM), and electrochemical analysis, are employed to understand the interaction between GO and the rose petal substrate. The techniques of FT-IR, EDS, XRD, SEM, energy band gap, and CV were used in characterize the synthesis of doped graphene using rose petals extract. The findings underscore the synergistic effects of this natural-synthetic hybrid system, opening pathways to innovative applications in flexible electronics, biosensors, and sustainable material design. The novelty of this research lies in its foundational exploration of integrating graphene oxide with organic substrates like rose petals, offering a new direction for the development of environmentally benign graphene nanocomposites. Green chemistry based novel nanocomposite may open up new avenues for production of graphene oxide homogenious dispersion with rose-petal extract.

Synthesis of carboxamide sensors for neurotoxic Cu2+ ions in safer green solvents and reaction conditions

Green amidation is simple and efficient for the synthesis of drugs and biomolecules. Green chemistry synthesis is always directed at achieving sustainability. Neurotoxins are critical targets for metabolic medicines to capture and eliminate from the body. Copper is a fatal brain neurotoxin. The C1-C4 probes were synthesized by reacting 3-coumarin carboxylic acid with 4-phenyl butyl amine, N-ethyl benzylamine, 4-dodecylaniline, and 3,3 - diphenyl propylamine in polar green solvent ethanol. These were tested for their metal-binding ability in environmentally safe aqueous acetonitrile with hyphenated techniques. The probes show significant binding with Cu2+ ions in the aqueous acetonitrile. The ascending order of anti-neurotoxin action is C3>C4>C2>C1 seen in the Limit of detection (Lod) values. Also, molecular mechanics (MM2) descriptors firmly point towards their use as drugs.

Superior photocatalytic degradation of pharmaceuticals and antimicrobial Features of iron-doped zinc oxide sub-microparticles synthesized via laser-assisted chemical bath technique

Addressing the dual challenges of antimicrobial resistance and pharmaceutical contamination in wastewater is crucial for global health and environmental preservation. Predictions estimate up to 10 million annual deaths by 2050 due to antimicrobial resistance, underscoring the urgent need for innovative solutions. This study explores the potential of zinc oxide Sub-Microparticles (ZnO SMPs) doped with iron (Fe) to enhance the photocatalytic degradation of pharmaceutical compounds in water and improve antimicrobial efficacy. A green laser-assisted chemical bath synthesis method created ZnO SMPs with varying Fe dopant concentrations (1 %, 1.5 %, and 3 %). The synthesized Sub-Microparticles underwent rigorous structural analysis using X-ray diffractometry, SEM, EDX, FTIR, and UV–visible spectrophotometry techniques. Their photocatalytic performance was evaluated in the degradation of paracetamol under blue laser light, and their antimicrobial properties were assessed following CLSI guidelines. Structural analyses confirmed the hexagonal wurtzite structure of ZnO SMPs, with noticeable changes due to Fe doping, including a transition from sub-microrods to sub-microsheets and a redshift in the optical band gap. Photocatalytic tests revealed a significant enhancement in paracetamol degradation efficiency, increasing from 53.41 % with pure ZnO to 98.99 % with 3 % Fe-doped ZnO in 50 min. Antimicrobial assays demonstrated an increased inhibitory effect against pathogens, with Fe-doped ZnO outperforming control discs. This study substantiates the potential of Fe-doped ZnO SMPs in wastewater treatment and antimicrobial applications, showcasing significant improvements in photocatalytic degradation of pharmaceutical compounds and antimicrobial efficacy. The findings underscore the importance of continuing research in this domain for environmental and public health benefits.

Photocatalyzed Synthesis of a Schiff Base via C-N Bond Formation: Benzyl Alcohol as Sustainable Surrogates of Aryl Aldehydes.

The advancement of photocatalytic techniques has enabled green chemical synthesis through visible-light-mediated photochemical oxidation under mild conditions. A novel approach under visible-light conditions was facilitated by eosin-Y for the reaction between substituted benzyl alcohols and anilines, resulting in the synthesis of diverse Schiff bases. This innovative method is emphasized for its environmentally friendly nature, lack of metal catalysts, cost-effectiveness, and nontoxic characteristics.

Sustainable Synthesis of Silver Nanoparticles Using Plant-Based Waste Biomass for the Removal of Cationic Dyes-A Review

Silver nanoparticles (AgNPs) have been the subject of researchers due to their unique properties such as optical, antimicrobial, and electrical properties depending on size and shape. This review focuses on their green synthesis of nanoparticles, metal nanoparticles and mainly AgNPs. Green chemistry synthesis method has attracted great attention as an alternative method in recent years because it is more energy efficient, safer and less toxic. At the same time, this study gives a general idea about the preparation of AgNPs by green synthesis method using lignocellulosic biomass. One of the main uses of lignocellulosic wastes in a circular economy is to introduce renewable resources into the market and on the other hand, to promote the valorization of waste. Moreover, lignocellulosic raw materials expand the sustainability possibilities of industrial processes as a result of their low cost and low environmental impact. On the other hand, dyes, which are wastes from different industries such as textile, plastic, food and paper, are the main cause of water pollution. This study provides a detailed investigation of the removal performance of AgNPs obtained using different lignocellulosic biomass for environmentally harmful cationic dyes.

A Ride on The Current State of Silver Nanoparticles in Health: What is The Next Stop?

Silver nanoparticles (AgNPs) are known for their broad scientific and technological applications, among which those related to their bioactivity stand out the most. Its antimicrobial, antioxidant, anti-inflammatory, anti-obesity, antifouling, and biosorption properties have been widely studied and analyzed. Furthermore, numerous strategies are being investigated to overcome the main limitation of AgNPs, their cytotoxicity, such as the development of green chemistry synthesis methods using plant extracts or the use of support materials for controlled release of nanoparticles. However, the methodologies currently used in this line of research limit these nanomaterials from eventually being used in the clinic. It is necessary to implement animal models and interdisciplinary collaboration with biomedical research groups to develop therapies based on AgNPs that may be able to have an impact on the health of patients.

Biosynthesized and chemically synthesized Ag/TiO2 nanocomposites: Effect of reaction parameters on synthesis using watermelon rind extract and comparative analysis

This work synthesized Ag/TiO2 nanocomposite via an aqueous reduction method using a green and chemical reducing agent. Citrullus lanatus (watermelon) rind extract (WMRE) and sodium borohydride (NaBH4) were used as the reducing agents during green synthesis and chemical synthesis, respectively. During green synthesis, a pH of 12, a reaction time of 45 min, and an operating temperature of 100 °C yielded the best visible light activity. The biosynthesized and chemically-synthesized Ag/TiO2 were compared using UV–Vis spectroscopy, X-ray fluorescence spectroscopy (XRF), X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive spectroscopy-scanning electron microscopy (EDS-SEM) and transmission electron microscopy (TEM). Synthesis using WMRE yielded spherical Ag nanoparticles modified on the surface of TiO2 nanoparticles. The Ag nanoparticles had enhanced monodispersity with an average diameter of 7.48 ± 4.06 nm. Therefore, the developed WMRE green synthesis method provides a simple, less chemical-intensive, and effective alternative to chemical synthesis.

Biosynthesis of Indigo Dyes and Their Application in Green Chemical and Visual Biosensing for Heavy Metals.

Fermentative production of natural colorants using microbial strains has emerged as a cost-effective and sustainable alternative to chemical synthesis. Visual pigments are used as signal outputs in colorimetric bacterial biosensors, a promising method for monitoring environmental pollutants. In this study, we engineered four self-sufficient indigo-forming enzymes, including HbpAv, bFMO, cFMO, and rFPMO, in a model bacterium E. coli. TrxA-bFMO was chosen for its strong ability to produce indigo under T7 lac and mer promoters' regulation. The choice of bacterial hosts, the supplementation of substrate l-tryptophan, and ventilation were crucial factors affecting indigo production. The indigo reporter validated the biosensors for Hg(II), Pb(II), As(III), and Cd(II). The biosensors reported Hg(II) as low as 14.1 nM, Pb(II) as low as 1.5 nM, and As(III) as low as 4.5 nM but increased to 25 μM for Cd(II). The detection ranges for Hg(II), Pb(II), As(III), and Cd(II) were quantified from 14.1 to 225 nM, 1.5 to 24.4 nM, 4.5 to 73.2 nM, and 25 to 200 μM, respectively. The sensitivity, responsive concentration range, and selectivity are comparable to β-galactosidase and luciferase reporter enzymes. This study suggests that engineered enzymes for indigo production have great potential for green chemical synthesis. Additionally, heterologous biosynthesis of indigo production can lead to the development of novel, low-cost, and mini-equipment bacterial biosensors with zero background noise for visual monitoring of pollutant heavy metals.

Phthalocyanines Synthesis: A State-of-The-Art Review of Sustainable Approaches Through Green Chemistry Metrics.

Driven by escalating environmental concerns, synthetic chemistry faces an urgent need for a green revolution. Green chemistry, with its focus on low environmental impacting chemicals and minimized waste production, emerges as a powerful tool in addressing this challenge. Metrics such as the E-factor guide the design of environmentally friendly strategies for chemical processes by quantifying the waste generated in obtaining target products, thus enabling interventions to minimize it. Phthalocyanines (Pcs), versatile molecules with exceptional physical and chemical properties, hold immense potential for technological applications. This review aims to bridge the gap between green chemistry and phthalocyanine synthesis by collecting the main examples of environmentally sustainable syntheses documented in the literature. The calculation of the E-factor of a selection of them provides insights on how crucial it is to evaluate a synthetic process in its entirety. This approach allows for a better evaluation of the actual sustainability of the phthalocyanine synthetic process and indicates possible strategies to improve it.

Click chemistry beyond metal-catalyzed cycloaddition as a remarkable tool for green chemical synthesis of antifungal medications.

Click chemistry is widely used for the efficient synthesis of 1,4-disubstituted-1,2,3-triazole, a well-known scaffold with widespread biological activity in the pharmaceutical sciences. In recent years, this magic ring has attracted the attention of scientists for its potential in designing and synthesizing new antifungal agents. Despite scientific and medical advances, fungal infections still account for more than 1.5 million deaths globally per year, especially in people with compromised immune function. This increasing trend is definitely related to a raise in the incidence of fungal infections and prevalence of antifungal drug resistance. In this condition, an urgent need for new alternative antifungals is undeniable. By focusing on the main aspects of reaction conditions in click chemistry, this review was conducted to classify antifungal 1,4-disubstituted-1,2,3-triazole hybrids based on their chemical structures and introduce the most effective triazole antifungal derivatives. It was notable that in all reactions studied, Cu(I) catalysts generated insitu by the reduction in Cu(II) salts or used copper(I) salts directly, as well as mixed solvents of t-BuOH/H2O and DMF/H2O had most application in the synthesis of triazole ring. The most effective antifungal activity was also observed in fluconazole analogs containing 1,2,3-triazole moiety and benzo-fused five/six-membered heterocyclic conjugates with a 1,2,3-triazole ring, even with better activity than fluconazole. The findings of structure-activity relationship and molecular docking of antifungal derivatives synthesized with copper-catalyzed azide-alkyne cycloaddition (CuAAC) could offer medicinal chemistry scientists valuable data on designing and synthesizing novel triazole antifungals with more potent biological activities in their future research.

Engineering 2D Photocatalysts for Solar Hydrogen Peroxide Production

AbstractSolar energy can be utilized in photocatalysis technology to realize light‐driven hydrogen peroxide (H2O2) production, a green chemical synthesis route. Designing high‐performance photocatalysts is critical to achieving practical solar H2O2 production. During the past decade, significant research progress is made in photocatalytic materials for H2O2 production. Particularly 2D materials‐based photocatalysts stand out due to their unique physical and chemical properties. This review highlights the intricate relationship between 2D material innovation and photochemical H2O2 production. It starts with the fundamental principles of photochemical H2O2 generation, focusing on crucial steps such as photon absorption, carrier dynamics, surface reactions, and the challenges that 2D materials can solve at each step. Then, various 2D materials‐based photocatalysts for solar H2O2 production are introduced in detail. Engineering strategies to optimize the photocatalytic performance are discussed afterward. Finally, the challenges and future opportunities for designing 2D materials‐based photocatalysts for solar H2O2 production are outlined. This review is expected to inspire the engineering of 2D materials‐based photocatalysts for the green synthesis of H2O2 and the conversion of solar energy to other chemicals.

Experimental study of diphenylmethane gasification with supercritical CO2

Supercritical carbon dioxide (SCCO2) gasification reaction is one of the current popular research fields with wide application prospects in green chemical synthesis, environmental protection and energy conversion. This work aimed to investigate the effects of different conditions on the gas–liquid-solid three-phase products during the reaction of SCCO2 gasification of diphenylmethane. As a result, the carbon gasification efficiency (CE) and the hydrogen gasification efficiency (HE) were 25.99 % and 21.97 % respectively at 700 ℃ for 40 min, in which the CO reached the maximum of 15.64 ± 0.16 mol/kg. As the temperature and residence time increased, the apparent morphology of solid products became more homogeneous. In addition, based on the theories of cleavage of free radicals, secondary cleavage of free radicals and binding of free radicals, three pathways for the generation of fluorene, biphenyl and m-terphenyl were postulated. The experimental results provide fundamental data and theoretical support for an in-depth understanding of the reactions mechanism under the SCCO2 atmosphere, which is of great significance for deepening our knowledge of supercritical carbon dioxide reduction reactions and promoting green chemical synthesis research.

Catalytic hydrogenolysis of sorbitol to glycols over chromium oxide silica: Effect of chromium loading

Cr2O3-SiO2 (CrSi) catalysts were prepared using the sol-gel method with varying Cr2O3 loadings (5%, 10%, 15%, 20%, and 25% by weight). The physical properties of the synthesized catalysts were characterized through N2 physisorption analysis, X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), and Scanning Electron Microscopy (SEM). Additionally, NH3-TPD analysis was employed to assess the acidity of the catalysts. The results indicated the presence of ordered mesopores with uniform pore sizes in the synthesized catalysts. The 20CrSi catalyst exhibited high total acidity, which correlated with its catalytic performance. The catalytic activities of the synthesized samples were tested in the sorbitol hydrogenolysis reaction to produce propylene glycols (PG) and ethylene glycols (EG) in a stirred high-pressure reactor under various process conditions. It was found that 20CrSi catalyst recorded maximum sorbitol conversion (70.08%) at optimum reaction condition. The catalyst was reusable up to 5 times with only a minor activity loss. This work contributes to sustainable and green chemical synthesis from renewable sources, offering insights into catalyst design for efficient glycol production.

Green synthesis of copper oxide nanoparticles using christia vespertilionis aerial parts extract: A sustainable approach for antibacterial efficacy assessment

Metal nanoparticles typically exhibit sizes ranging from 1 to 100 nanometers and can be produced by several techniques, such as green synthesis and chemical synthesis. This study focuses on the green synthesis of copper oxide nanoparticles (CuO-NPs) using aerial extract of Christia vespertilionis. The observation of CuO-NPs formation was made based on the variations in colour exhibited by the extract mixture following the introduction of copper (II) sulphate (CuSO4). The synthesised nanoparticles underwent characterization utilising various instrumentation techniques, including UV-Vis spectrophotometry, FTIR, TEM, SEM, EDX, and TGA. The antibacterial activity of these nanoparticles was assessed by using disc diffusion method, against selected Gram-positive and Gram-negative bacteria. The investigation also encompassed an examination of the combined effect of the nanoparticles and the antibiotic Ciprofloxacin on antibacterial activity. In this study, it was noted that the maximum absorbance of the CuO-NPs occurred at a wavelength of 253nm. The functional groups of the CuO-NPs were confirmed through FTIR spectrum. TEM analysis revealed the average particle size of the CuO-NPs as 62.16 nm. Additionally, examination of SEM images revealed that the particles exhibited irregular shapes while maintaining a homogeneous distribution. The nanoparticles exhibited enhanced antibacterial efficacy against Gram-positive bacteria in comparison to the Gram-negative bacteria that were examined. Significant synergistic effect was shown when the CuoNPs were used with the antibiotic against the bacteria tested. In conclusion, the study conducted demonstrates favorable outcomes as an antibacterial agent and recommended to conduct additional research to investigate the mechanism of action and toxicity of this agent.

N-CoFeP/NF electrocatalyst for coupling hydrogen production and oxidation reaction of various alcohols

Replacing the oxygen evolution reaction with the alcohols oxidation reaction (AOR) in electrolytic water is not only expected to reduce the overall energy consumption, but also realize the green synthesis of high value-added chemicals. However, designing high-activity electrocatalysts toward AOR yet faces a daunting challenge due to the indefinite conversion mechanism of different alcohols. Herein, a self-supported N-CoFeP/NF electrocatalyst on a nickel foam is synthesized via hydrothermal method, followed by low temperature nitriding and phosphating. The N-CoFeP/NF exhibits a fine nanorod nanostructure and high crystallinity. The AOR using N-CoFeP/NF catalysts requires a significantly lower potential (1.38–1.42 V vs. RHE) at 100 mA cm−2, reducing the energy input and the improvement of the overall efficiency. Moreover, alcohols with secondary hydroxyl groups located in the middle of the carbon chain underwent CC bond breakage during oxidation, yielding primarily formic acid (FE = 74 %) and acetic acid (FE = 50 %), which exhibits more attractive performance than alcohols with primary hydroxyl groups located at the end group did not undergo chemical bond breakage at a high current density of 400 mA cm−2. This study provides a novel and effective method to design TMPs and the selection of alcohols for anodic reaction, which can be used as a versatile strategy to improve the performance of anodic AOR coupled hydrogen evolution.