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The investigation of organic synthesis with bio-waste materials has emerged as a high researched field owing to its environmentally benign methodology. The current work presents the Water Extract of Papaya Peel Ash (WEPPA) as a reusable and green catalyst for the efficient synthesis of the acrylidene malononitrile derivatives, thus forming C–C bonds via Knoevenagel condensation reaction. The catalyst underwent further characterization using several techniques such as Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX), and high-resolution transmission electron microscopy (HR-TEM) methods. The presence of basic sites in WEPPA promotes its use as a catalyst in the synthesis of acrylidene malononitrile derivatives. The isolated product did not necessitate any column chromatographic purification and was recrystallized using hot ethanol. A total of nine derivatives were synthesized rapidly at room temperature within 2–15 min, yielding an excellent range of 89–94% and subsequently verified using nuclear magnetic resonance (NMR) and Fourier-transform infrared (FT-IR) spectroscopic techniques. In addition, the catalyst can be reused for up to four cycles with its efficiency being 91%, 89%, 87%, and 85% in 1st, 2nd, 3rd, and 4th cycle. [ABSTRACT FROM AUTHOR]

Water Extract of Pomegranate Ash (WEPA) emerges as a highly effective green catalyst in the one-pot multicomponent synthesis of orthoaminocarbonitrile tetrahydronaphthalene and its derivatives. The catalyst's utility extends to the novel synthesis of orthoaminocarbonitrile methyltetrahydronaphthalene, achieved through a reaction involving 4-methylcyclohexanone, malononitrile and aromatic aldehydes. The protocol boasts pleasing features including an easy workup procedure, short reaction time, high yield of products (92–96%) and a developed synthesis pathway that circumvents purification processes like chromatography. This research highlights the promising potential of WEPA as a green catalyst in the synthesis of valuable orthoaminocarbonitrile methyltetrahydronaphthalene compounds. Our research provides valuable insights into the stability and reactivity profiles of the derivatives of orthoaminocarbonitrile methyltetrahydronaphthalene through computational studies. DFT studies show that the synthesized compounds exhibit good reactivity, as the band gap of all compounds lies in the range of 4.4 eV. [ABSTRACT FROM AUTHOR]

To mitigate the emissions of greenhouse gases (GHGs) from fossil fuels, the use of biodiesel and its sustainable production have been receiving more attention over the past decade, especially for the reuse of waste cooking oils and non-edible oils as starting feedstocks. For the biodiesel production process, the suitability of a green catalyst is a core function in the transesterification reaction. Heterogeneous (solid-state) catalysts are generally superior to homogeneous (liquid-state) catalysts due to several significant advantages such as no saponification products formed, recyclability, and less equipment corrosion. Recent studies also revealed that heterogeneous solid base catalysts were widely used for the production of biodiesel. Furthermore, the use of biomass-based ash derived from herbaceous and agricultural biomass is increasing rapidly because of its environmental sustainability, high biodiesel yield, and low catalyst cost. To highlight alternative catalysts from biomass residues, this mini-review paper thus focused on a summary of various heterogeneous potassium-rich ash materials, which were used as green catalysts for the sustainable production of biodiesel. Due to the abundant quantity and chemical compositions, it was found that ash derived from cocoa pod husk may be the most commonly used solid base catalyst for producing biodiesel in the literature. Finally, future perspectives on biodiesel production by adopting emerging technologies and using high-potassium (K) biomass ash as a green catalyst were also addressed. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to produce an engineered recombinant laccase from extremophilic Halalkalibacterium halodurans C-125 (Lac-HhC-125) with higher protein yield, into a more active conformation and with properties that meet the fundamental needs of biotechnological application. Results: The rLac-HhC125 was partially purified by size exclusion chromatography and concentrated by ultrafiltration (10 kDa) with a yield of 57.6%. Oxidation reactions showed that adding 2 mM CuSO4 to the assay solution led to activating the laccase. To increase its initial activity, the rLac-HhC125 was treated at 50 °C for 20 min before the assays, improving its performance by fourfold using the syringaldazine as a substrate. When treated with EDTA, methanol, ethanol, and DMSO, the rLac-HhC125 maintained more than 80% of its original activity. Interestingly, the acetonitrile induced a twofold activity of the rLac-HhC125. The putative rLac-HhC125 demonstrated a capability of efficient transformation of different organic compounds at pH 6, known as dye precursors, into coloured molecules. Conclusion: The rLac-HhC125 was active at high temperatures and alkaline pH, exhibited tolerance to organic solvents, and efficiently transformed different hydroxy derivatives into coloured compounds, which indicates that it can be used in various biotechnological processes. [ABSTRACT FROM AUTHOR]

Abstract In this study, the conversion of bones (waste of food industry) into bone char is described. The presence of calcium phosphate and graphitic carbon gives bone char unique properties, with different possible uses. The catalytic behavior of bone char modified with chlorosulfonic acid is tested as reusable and eco-friendly solid acid biocatalyst in synthesis of pyrimidine-5-carbonitrile derivatives. The catalyst properties were characterized by different techniques such as FT-IR, BET, SEM, TEM, TGA, EDS and XRD. The bone char catalyst can be reused several times without reducing catalyst efficiency. In addition to the various reported benefits, the first use of bone char as a catalyst support for organic synthesis is an important novelty of this study.

Nanoparticles (NPs) of cobalt oxide and Fe/Ni-doped cobalt oxide have been prepared by the co-precipitation method. XPS analysis established the chemical nature of these NPs in terms of atomic as well as molecular formulations, and EDAX analysis complemented the XPS results displaying the presence of Fe and Ni atoms in the cobalt oxide NPs revealing successful doping of Fe and Ni in cobalt oxide NPs. The impact of Fe and Ni-doping on the structure and physico-chemical properties of cobalt oxide NPs was also established by XPS analysis. The presence of metal-oxide bonds was further established by FTIR (Fourier transform infrared spectroscopy) and HRTEM (high-resolution transmission electron microscopy) analysis confirmed the formation of NPs. Among bare and Fe/Ni-doped cobalt oxide NPs, Fe-doped cobalt oxide NPs showed maximum photocatalytic activity against methylene blue as well as Fe-doped cobalt oxide NPs also acted as an excellent catalyst for the sulfoxidation of sulfides with 99% conversion and 95% selectivity under green reaction conditions utilizing water as a solvent. [ABSTRACT FROM AUTHOR]

A series of Mn+/silicalite-1 was prepared to be used as a Lewis acid heterogeneous catalyst for a one-pot multicomponent Biginelli reaction. The catalysts were characterized by FTIR, XRD, NH3-TPD, and BET. The mesoporous catalysts possess a pore diameter of 13.83 nm (138.3 Å), a surface area of 282.43 m²/g, and a pore volume of 0.98 cm3/g, which can facilitate the transport of reactants and products smoothly during the catalytic process. Besides the acidity of the catalyst, the maximum temperature of NH3-desorption plays an important role in the catalytic activity. Cr3+/silicalite-1 showed the most active catalyst, while Zn2+/silicalite-1 showed the most selective one. Besides DHPM derivatives as a major Biginelli product, C6-styril of DHPM and Knoevenagel products were isolated if the reaction was conducted using Cr3+/- and Fe3+/silicalite-1. Catalyst Cr3+/silicalite-1 can be used to produce DHPM attaching various substituents and showed a green catalyst potential due to its reusability capacity. [ABSTRACT FROM AUTHOR]

Researchers worldwide have increasingly focused on ionic liquids (ILs) in recent decades due to their distinctive properties and wide range of uses. Researchers are working on creating novel ILs and enhancing their characteristics to broaden their use across many industries. ILs are significant due to their versatility across various applications, and their utilization should take into account aspects such as cost, toxicity, and availability. Due to their unique properties, they have been extensively used as a green catalyst system in the synthesis of pyrazole derivatives. Pyrazole derivatives is privileged scaffolds among aza‐heterocycles owing to its various applications in drug discovery and materialistic program. A big task of green chemistry in organic synthesis has been fulfilled to the organic chemists towards the formation of valuable pyrazole‐based frameworks. This review explores the diverse applications of ILs in organic synthesis, specifically highlighting literature from 2004 to 2023 on the synthesis of pyrazole and its derivatives using IL‐assisted strategies. Specifically, it covers the synthesis of substituted pyrazoles, pyrazolo‐pyrans, quinolino‐triazolo‐triazepines, pyrazolo‐pyrimidines, and pyrazolo‐quinolinones. Also, reveals a role of IL as a catalyst and solvent on the synthesis of pyrazole derivatives. [ABSTRACT FROM AUTHOR]

The use of green heterogeneous catalysts that are obtained from waste agricultural biomass can make the production of biodiesel more economical. In this research, three solid base heterogeneous catalysts (Catalyst A, B, and C) were synthesized from kola nut pod husks, and the synergistic effects of the elemental composition on catalytic activities for biodiesel production were studied. The results revealed a high surface area of Catalysts A, B, and C at 419.90 m2/g, 430.54 m2/g, and 432.57 m2/g, respectively. Their corresponding pore diameters are 3.53 nm, 3.48 nm, and 3.32 nm, showing that the catalysts are mesoporous in nature. The X-ray Fluorescence (XRF) results revealed the presence of a variety of alkaline earth metals and their corresponding metal oxides in substantial amounts. Catalyst A was produced with the highest concentration of calcium at 40.84 wt.% and calcium oxide at 68.02 mole%. The substantial concentration of other elements, such as potassium, magnesium, and aluminum, and their corresponding metal oxides are the proof of high catalytic activity of the produced green catalysts. The high CaO contents of all three produced catalysts and their high surface areas indicate their strong potential for good catalytic activities applied to the synthesis of biodiesel. [ABSTRACT FROM AUTHOR]

AbstractAn efficient catalyst with silver encapsulated into mesoporous silica (Ag/MS) was prepared via a hydrothermal method. The characterization was done with FT IR, XRD, SEM, BET, and EDX, and the well-organized structure of Ag/MS catalyst has been approved. It is found as an efficient catalyst for the selective oxidation of styrene to benzaldehyde employing hydrogen peroxide as a green and economic oxidant. The effect of various reaction conditions including reaction time, reaction temperature, different kinds of solvents were studied on the catalytic performance. In the optimized reaction conditions, the conversion of benzaldehyde was achieved 72% to 93%. [ABSTRACT FROM AUTHOR]

This study explores the surface modification of polyethene terephthalate (PET) fabric via glycolysis, employing choline hydroxide as an eco-friendly catalyst. A range of chemicals was evaluated for catalysing the glycolysis reaction. Among them, choline hydroxide demonstrated notable enhancements in surface hydrophilicity, moisture regain, wicking properties, and water contact angle, surpassing other catalysts. Scanning Electron Microscopy (SEM) revealed a marked increase in surface roughness and irregularities following glycolysis in the presence of this ionic liquid. The surface modification technique employed in this investigation resulted in a decrease of less than 20% in the breaking force of the fabric. Fourier Transform Infrared (FT-IR) spectroscopy and the methylene blue staining method confirmed the emergence of free hydroxyl groups on the modified fabric's surface. These findings suggest that glycolysis catalysed by choline hydroxide is a promising approach for enhancing the surface characteristics of polyester fabrics, which may lead to improved functional properties in textile applications. [ABSTRACT FROM AUTHOR]

A relatively green one-pot environmentally benign protocol has been developed for the smooth access of 5- (Substituted-phenyl)-[1,3,4]thiadiazole-2-amine derivatives. Present research involved the cyclocondensation response of substituted fragrant carboxylic acid and thiosemicarbazide under microwave irradiation with the usage of PEG-400 as a green catalyst. The protocol was found to be an easy, cheaper, and metallic-free green medium. The remarkable features of the present investigation are safe and environmentally benign, inexpensive, and use of nontoxic and non-volatile PEG-400 as a medium. The present study involved direct condensation of aromatic carboxylic acid with thiosemicarbazide in a minimum reaction time to obtain an excellent yield of thiadiazol-2-amines. [ABSTRACT FROM AUTHOR]

The pursuit of renewable fuels for the transportation sector, particularly for combustion engines like diesel, is crucial in reducing greenhouse gas emissions. This study introduces an innovative strategy for biodiesel production utilizing marine macroalgae Ulva lactuca as the primary feedstock, emphasizing sustainability and resource efficiency. Lipids were extracted from the macroalgae via a Soxhlet process and characterized using GC–MS and FTIR to ascertain fatty acid composition and functional groups. The Cu–BTC@AC catalyst, synthesized from the lipid-extracted algae residue via pyrolysis and hydrothermal treatment, underwent characterization using SEM–EDS, XRD, and FTIR techniques. Subsequently, the Cu–BTC@AC catalyst was employed in the transesterification process to efficiently convert the extracted algal lipids into biodiesel, achieving a high yield of 92.56 % under RSM-optimized conditions: 65 °C temperature, 3.96 wt% catalyst amount, 15:1 methanol-to-lipid ratio, and 140 min reaction time. Kinetic and thermodynamic parameters for biodiesel production were calculated as follows: Ea = 33.20 kJ mol−1, ΔH# = 30.39 kJ mol−1, ΔS# = –165.86 J mol−1 K−1, and ΔG# = 86.48 kJ mol−1. GC–MS analysis identified a significant FAME content in the biodiesel, comprising 98.12 % of its composition. Notably, the Cu–BTC@AC catalyst exhibited excellent reusability, maintaining 80.21 % biodiesel yield after the third cycle. Moreover, physicochemical analysis of the biodiesel confirmed its compliance with ASTM D6751 specifications, underscoring its potential as a viable alternative fuel for the transportation sector.

Ribbon-like coordination polymers (CP) represents a highly unexplored innovative class of metal-coordination network. Herein, we have developed a highly scalable and chemically robust (pH = 3–10 stable) ribbon-like CP [{Cu(Pim)(L)(H2O)·H2O}]n (1) following a complete environment-friendly green synthesis route. Considering the presence of surface flanked labile coordinated water molecules and their appealing correlation with one-dimensional structural characteristics, such sort of ribbon-like CP was explored for the first time as excellent heterogeneous surface catalyst for largely unexplored three-component Hantzsch condensation for synthesis of different classes of dihydropyridine (DHP). Moreover, 1 is employed to synthesize bio-responsive drug ‘Ethidine’ (possessing high anti-oxidant and anticarcinogenic properties) characterized with Single Crystal X-ray Diffraction (SCXRD) analysis. Several DHP-based products are also analysed through in-depth SCXRD analysis. This report inaugurates the usage of a Cu(II) based ribbon-like CPs as heterogeneous surface catalyst following environmentally benign manner for synthesis of bioactive DHPs and Drugs.

1-(4-sulfobutyl)pyridinium chlorozincate ionic liquid was synthesised in high yield (89%) through a simple route and characterised using FT-IR, NMR, and HRMS spectroscopy. The one-pot reaction was employed for the condensation reaction of benzaldehydes, 5,5-dimethyl-1,3-cyclohexanedione, and dicyanomethane, utilising the prepared ionic liquid catalyst. The optimal conditions for the reaction were achieved with a catalyst loading of 10 mol%, a solvent mixture of water and ethanol (1:1, v/v), maintained at 100°C for 180 minutes. A broad spectrum of benzopyran-5(6H)-one derivatives was prepared, yielding moderate to good results. The notable features of this procedure include readily available substrates, short reaction times, the use of environmentally friendly solvents, and the elimination of the need for chromatography in the isolation of products. A new acidic pyridinium-based ionic liquid was successfully synthesised and used as a catalyst in the synthetic process of 2-amino-3-cyano-4-phenyl-7,7-dimethyl-7,8-dihydro-4H-1-benzopyran-5(6H)-ones. These reactions involved a condensation reaction of aromatic benzaldehydes, 5,5-dimethyl-1,3-cyclohexanedione, and dicyanomethane in a solvent mixture of ethanol and water, resulting in the desired products in moderate to good yields. The procedure is efficient and eco-friendly, and the products can be easily obtained by recrystallisation. Thus, this protocol offers an alternative to existing methods.

A novel acid–base nanocatalyst (MNPs@Alg-Pr-His) was synthesized using available materials (nanomagnetic alginate core and histidine) via a facile strategy. After characterization, its efficiency was investigated in the synthesis of 2-amino-4H-chromene and 1,2,3,6-tetrahydropyrimidine derivatives. This nanobiocatalyst showed remarkable catalytic efficiency in both reactions (the reaction yields for the first reaction: 89–96% and for the second reaction: 68–85%). This catalyst was reusable and recyclable and still showed good activity after five runs. The antibacterial effect of the histidine, alginate, and MNPs@Alg-Pr-His was evaluated against a Gram-positive bacterium (S.aureus) and a Gram-negative bacterium (E. coli) by the disk diffusion method. It is noticeable that MNPs@Alg-Pr-His, unlike histidine and alginate, showed more antibacterial activity against Gram-negative bacterium (28.0 ± 1.4) than Gram-positive bacterium (19.0 ± 1.4). [ABSTRACT FROM AUTHOR]

Low catalytic activity, scarcity of resources, design complexity, high cost, and unfavourable nature of non-traditional metal and its composites limit their utilization as cathodes in microbial fuel cells (MFCs). This research aimed to identify the most effective new cathode catalyst for use in one chamber air cathode microbial fuel cells by comparing two graphite-based nanomaterials of Reduced Graphene Oxide Hydrogen iodide - Acetic acid (rGO HI-AcOH) and Reduced Graphite Oxide Nickel Nanoparticles (rGO/Ni) composite. The behavior of microbial fuel cells was calculated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Since the rGO HI-AcOH cathodes were more efficient, the MFCs produced maximum power (>37%) than the rGO/Ni Nanoparticles cathode MFCs. The double loading (DL) rGO HI-AcOH cathodes in the Microbial Fuel Cells produced the maximal power densities at 1691 ± 34 mW/m2 (CE = 73 ± 5%), covering 78% of the power densities calculated for Platinum/Carbon (Pt/C) (2203 ± 52 mW/m2; CE = 82 ± 3%). With a double catalyst load, MFCs using rGO/Ni Nanoparticles composite anodes produced more power than the others (1016 ± 31 mW/m2, CE = 71 ± 3%). Excellent concordance was seen between CV and EIS and the MFC findings. Based on the results of this research, the rGO HI-AcOH cathode loaded with two catalysts has the potential to produce long-lasting, environmentally friendly materials at low cost and maintain consistent power output and the reliable operation of MFCs throughout their useful lifetimes. • Nano-cathode catalysts rGOHI-AcOH and rGO/Ni tested for boost-up MFCs power output. • Long-lasting eco-friendly Cathode catalyst rGOHI-AcOH for reliable operation of MFC. • Single double and Triple load considered with rGOHI-AcOH & rGO/Ni cathode catalysts. • MFC produced maximal power densities at 1691 ± 34 mW/m2 with DL rGOHI-AcOH cathodes. • rGOHI-AcOH cathode cost is 73% less than the Platinum/Carbon cathode. [ABSTRACT FROM AUTHOR]

The catalytic mechanism of rice straw, Oryza Sativa L., on the carbonation of shrimp farm sludges via the gasification process was investigated in this work. Rice straw possessed 75% of its weight is silicon dioxide (SiO 2) which can be utilized as an effective catalyst whereas the tar decomposition and gas production during the thermochemical process can be enhanced. In that manner, the influence of working temperature (oC), the ratio (%wt) on the amount of rice straw used in the shrimp farm sludges, and the moisture content (%) in the prepared samples are taken into account to determine the role of rice straw catalytic. Gasification processes were carried out in 60 min in a stainless steel reactor, with a feeding rate of 0.5 kg/h and an air-pumped flow rate of 2 L/min. All experiments were performed under different conditions of working temperatures (600, 700, 800, and 900 °C), sample composition (0, 20, 40, and 60 %wt of rice straw added), and moisture content of the feedstock (20, 40, 60, 80, and 90%). It is essential to confirm that the change in sample moisture content and the working temperature are also significant to the production of hydrogen throughout the process. As the moisture content increase from 20 to 40%, the hydrogen yield is proportionally increased by 5–10%. On the aspect of working temperature influence, the hydrogen composition increased from 11% at 600 °C to 27% at 900 °C for the RS sample, from 13% at 600 °C to 29% at 900 °C for the RS20, from 17% at 600 °C to 35% at 900 °C for the RS40 sample, and from 19% at 600 °C to 43% at 900 °C for the RS60 sample. The findings in this work confirm the rice straw catalyst's role in enhancing hydrogen production via the gasification process. Furthermore, this work provides guidance information for simple but effective processes that can not only deal with the sludge waste management issue but also create a waste-to-energy route suitable for medium and small-scale aquaculture businesses. [Display omitted] • Introducing an effective method to utilize the shrimp farm sludges. • Demonstrates the catalyst role of rice straw during gasification. • Enhancing hydrogen production from the source of sludges. • Providing a simple and effective waste-to-energy process. • Evaluating the role of moisture during the thermochemical process. [ABSTRACT FROM AUTHOR]

Due to their fascinating biological features, heterocyclic compounds and their derivatives have long been recognized as promising molecules with potential pharmaceutical applications. The significance of heterocyclic compounds in drug discovery and development is evident from the fact that a majority of drugs in the pharmaceutical market incorporate heterocyclic compounds as active substances or ingredients. Various synthetic methods and advancements have been devised to prepare these heterocyclic compounds using diverse catalysts under mild reaction conditions. SO3H functionalized carbon material (C‐SO3H) is heterogeneous green solid catalyst that has been employed to catalyze diverse organic reactions including construction of three‐, four‐, five‐, six‐member and fused heterocycles as well as other open chain organic transformations. The C‐SO3H catalyst works under relatively mild reaction conditions and recovered from the reaction mixtures for reuse. Various cheap carbon sources covering natural organic carbon matter and industrial waste already being used to synthesize SO3H‐functionalized acidic carbon catalyst for replacement of various homogeneous acid catalysts. The present review aims to highlight the organic reactions especially those connecting for heterocyclic synthesis catalyzed by sulfonated carbons (C‐SO3H) from 2010 to till date. [ABSTRACT FROM AUTHOR]

Green nanocatalysts play a crucial role in organic synthesis. In this study, a novel approach utilizing marine diatom extract is presented for the production of tin oxide nanoparticles (SnO2 NPs). These NPs possess distinctive characteristics, including crystalline properties, a spherical shape, and an average size of 20 ± 2 nm. The reduction and surface coating of the NPs involve organic components derived from marine sources. The resulting SnO2 NPs serve as highly effective catalysts for the synthesis of chromeno[4,3‐b]quinoline derivatives, facilitated by ultrasound‐assisted reactions. This process demonstrates remarkable efficiency, yielding a variety of organic products with impressive results, reaching yields of 82–97% and requiring short reaction times. Moreover, the SnO2 nanocatalyst employed exhibits advantageous properties, such as low loading, durability, and the ability to be reused up to six cycles. [ABSTRACT FROM AUTHOR]

In this study, the main target is to obtain high grade light commercial motor fuels from the catalytic cracking of the gas oil fraction by using a modified green catalyst biochar. For this aim, initially the biochar has been impregnated with the spent pickling liquor to acquire a catalyst being strong cracking activity under certain conditions. By using of the catalyst activated via the spent pickling liquor, the catalytic cracking runs have been carried out on the gas oil at different catalyst additive rates in ranging from 5 wt.% to 20 wt.% to obtain light liquid hydrocarbon fractions at the temperature of 500°C and heating rate of 10 °/min. The n-pentane soluble fraction of the catalytic cracking liquid obtained from the use of activated char catalyst at additive rate of 20 wt.% has a low sulphur content and also consisted of short straight chain paraffinic hydrocarbons with carbon number of C13, C17, and C18 compared to those of the thermal and non-activated catalyst. Consequently, the activated catalyst has a considerable potential as a green catalyst with low cost for the converting of heavy hydrocarbons into light and more valuable hydrocarbons. [ABSTRACT FROM AUTHOR]

In this paper, a novel efficient utilization of lignin‐based nanomagnetic copper (I) is presented as an eco‐friendly recoverable catalyst. We report a simple one‐pot synthesis of magnetic copper chloride (I) composite by using lignin as a reducing agent and heterogenized support. The copper (I) nanocomposite shows high catalytic potential in one‐pot three component click reaction for synthesis of 1,2,3‐triazoles, with excellent turnover efficiency even after 4 cycles in green conditions. The lignin‐copper (I) chloride magnetic nanocomposite catalyst demonstrates highly efficient, stable and recyclable copper (I), and cost effectiveness advantages. The catalyst is easily recovered by an external magnetic field, and therefore, time and energy are saved since there is no filtration or decantation technique. Also, the stable nanomagnetic copper (I) can be handily prepared and applied for large scale operations. Besides, due to totally clear of nanomagnetic copper (I) away from the reaction media, the desired highly pure products can be achieved in excellent yields. High thermal stability of nanomagnetic copper (I) turns its ability to be useable in organic reactions under high temperatures. According to high dispersibility in aqueous solvent, nanomagnetic copper (I) can be utilized as highly efficient catalyst. The prepared composite is characterized by SEM, TEM, XRD, EDX, TGA, VSM and FT‐IR. [ABSTRACT FROM AUTHOR]

A facile, efficient, green synthetic route was developed for the selective synthesis of 2-substituted benzimidazole derivatives via the reaction of 1,2-diamines with aromatic, aliphatic and hetero aromatic nitroalkenes in the presence of an onion extract as a green catalyst. In this reaction, fifteen 2-substituted benzimidazole derivatives were obtained in good to excellent yields (80-95%). The method presented here offers several benefits, including minimal energy usage, cheap, nontoxic catalyst, simple workup procedure and without column purification. The usage of onion extract creates this approach is environmentally friendly and makes a significant addition to the currently available techniques for the creation of 2-substituted benzimidazoles. Further, the scope and constraints were also investigated, and a conceivable reaction mechanism was put forth. [ABSTRACT FROM AUTHOR]

The development of new fuel sources to replace nonrenewable fossil fuels has received substantial attention due to the ongoing demand for fossil fuels. Biomass and raw waste materials are crucial sources to produce suitable alternative fuels instead of nonrenewable fuels and offer a greener approach. Therefore, improving the fuel properties of biooils produced from the thermochemical conversion of biomass and raw waste materials is critical as it is used as an alternative to nonrenewable fuel. Developing an economical and eco-friendly method to produce sustainable and renewable oil by improving biooil containing large amounts of phenolic compounds has become imperative. One of the most intriguing and promising technologies for refining biooil to produce renewable fuels of comparable quality to conventional fossil fuels is the hydrodeoxygenation (HDO)-based process for converting biooil to renewable fuels. This method is almost one of the best improving methods described in the literature. At this point, it is of great importance that the HDO process is carried out catalytically. Carbon materials are preferred for both designing catalysts for HDO and supporting metal nanoparticles by providing chemically inert surfaces and tunable functional groups, high surface area and active sites. The HDO of biomass and raw waste materials has significantly advanced thanks to carbon-based catalysts. In this review, the effect of the surface character and catalytic ability of the carbon support, especially prepared by the green synthesis technique, on the HDO reaction during biooil improvement is discussed. Moreover, HDO reaction parameters and recent studies have been investigated in depth. Thus, green carbon catalysts' role in clean fuel production via the HDO process has been clarified. [ABSTRACT FROM AUTHOR]

Bovine Serum Albumin (BSA) was used as a green, inexpensive and efficient biocatalyst, for synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione and 1H-pyrazolo[1,2-a]pyridazine-5,8-dione derivatives through a one-pot three component reaction between phthalhydrazide or maleic hydrazide, Aryl aldehydes, and malononitrile in good to excellent yield (73–93%). The remarkable features of this approach include green catalyst, no organic solvent, metal-free, mild reaction, easy work-up and good functional group tolerance. [ABSTRACT FROM AUTHOR]

In the present study, silica‐alumina rich river clay calcined at different temperatures are used as low cost natural green catalyst for the production of valuable aromatics benzene, toluene and ethylbenzene (BTE) via multiphase/Mp‐type catalytic pyrolysis of waste expanded polystyrene (WEPS). The calcined river clay catalysts are designated as RHC‐600, RHC‐700, RHC‐800 and RHC‐900 after calcination at the temperature of 600 °C, 700 °C, 800 °C, and 900 °C, respectively. Whereas, the natural river harvested clay is designated as RHC. The RHC‐800 catalyst is found to be the best catalyst for the WEPS pyrolysis due to its highest surface area of 18.83 m2/g and high silica to alumina (Si/Al) ratio of 2.23 among all other river harvested clay catalysts. The styrene content get reduced from 84.74 wt.% to 65.30 wt.% and BTE content increased from 11.38 wt.% to 23.51 wt.% when the process is switched over from thermal to Mp‐type catalytic pyrolysis using RHC‐800 catalyst. The promising results of RHC‐800 indicate that it can be an alternative to commercial catalyst for pyrolysis applications. [ABSTRACT FROM AUTHOR]

Environmental concerns due to the release of industrial wastewater contaminated with dyes are becoming more and more intense with the increasing industrialization. Decolorization of industrial effluents has become the top priority due to the continuous demand for color-free discharge into the receiving water bodies. Different dye removal techniques have been developed, among which biodegradation by laccase enzyme is competitive. Laccase, as a green catalyst, has a high catalytic activity, generates less toxic by-products, and has been extensively researched in the field of remediation of dyes. However, laccase's significant catalytic activity could only be achieved after an effective immobilization step. Immobilization helps strengthen and stabilize the protein structure of laccase, thus enhancing its functional properties. Additionally, the reusability of immobilized laccase makes it an attractive alternative to traditional dye degradation technologies and in the realistic applications of water treatment, compared with free laccase. This review has elucidated different methods and the carriers used to immobilize laccase. Furthermore, the role of immobilized laccase in dye remediation and the prospects have been discussed. [ABSTRACT FROM AUTHOR]

Alum-catalyzed Knoevenagel reaction of substituted aromatic aldehydes and active methylene compounds such as malononitrile and barbituric acid using green, eco-friendly solvent, water was developed. The protocol is practically simple and found efficient. The condensation is carried out in a short reaction time and the desired products are obtained in excellent yields. Furthermore, The catalyst utilized is readily accessible, cost-effective, environmentally friendly, and safe. The derivatives are among the most frequently used intermediate in heterocyclic synthesis. The synthesized benzylidene derivatives were characterized by spectral analysis. [ABSTRACT FROM AUTHOR]

Arginine, one of the basic amino acids known as green catalysts for sugar isomerization, was used to isomerize ribose to ribulose, a rare keto-pentose sugar, and the effects of reaction conditions on the yield of ribulose and degree of browning were investigated using a batch-type reactor. The initial pH of the mixture of ribose and arginine was in the range of 9.39–10.01. A high yield of ribulose and low degree of browning of the reaction mixture were achieved at a molar ratio of arginine to ribose of 0.05 and a temperature of 110 °C. To achieve the highest possible ribulose concentration, an initial ribose concentration of 0.75 mol/L was preferable. It was found that once isomerization had progressed, acidic by-products caused a reduction in pH and brown-colored compounds were continuously formed. This study showed that the method used is relatively simple and effective for producing ribulose. [Display omitted] • Arginine, a common amino acid used as food additive, was used as a catalyst. • Ribose was isomerized to ribulose in arginine solution at 90–100 °C. • Approximately 9 % yield of ribulose was obtained within 10 min of reaction. • Absorbance at 280 and 420 nm continued to increase. [ABSTRACT FROM AUTHOR]

Reaction of glucose or galactose was performed in arginine solution or phosphate buffer (pH 7.0) using a batch reactor at 110°C. The yields of products, pH, and absorbances at 280 and 420 nm were measured during the reaction. Fructose, mannose, and allulose were formed from glucose; tagatose, talose, and sorbose were done from galactose. The reaction proceeded more rapidly in arginine solution than in phosphate buffer. In arginine solution, yields of fructose and tagatose were 20% and 16%, respectively, after 30-min reaction; in phosphate buffer, they were 14% and 10%, respectively. However, in both reaction media, the pH drop and increase in absorbances continued even after the yield became almost constant. The absorbance increased particularly in the latter half of the reaction due to formation of browning products. Therefore, to avoid browning, the reaction should be stopped as soon as possible after the yield approaches its maximum value. [ABSTRACT FROM AUTHOR]

In this study, platinum-based silver nanoparticles (Pt@Ag NPs) were synthesized by the green synthesis method, and their catalytic effects on hydrogen production were investigated. The characterization measurements of the synthesized NPs were performed by TEM, UV–Vis, XRD, and FTIR. According to TEM characterization results, Pt@Ag NPs had an average size of 5.431 nm. In experiments based on catalytic reactions for hydrogen production, test measurements were made at different parameters. It was observed that as the concentrations of the substrate and catalysts increased, the catalytic reaction accelerated, and the hydrogen release increased. Likewise, it was determined that hydrogen production increased with increasing temperature in different temperature experiments. The turnover frequency, entropy, activation energy, and enthalpy values are calculated as 702.38 h−1, -160.5 J/mol.K, 32.48 kJ/mol, and 29.94 kJ/mol, respectively. According to the reusability test results, it was observed that the average reusability was found to be 85% after 5 cycles and it was confirmed that the NPs showed high-catalytic activity. In addition, the biological activities of Pt@Ag NPs, including antimicrobial, antioxidant and anticancer were tested. Pt@Ag NPs synthesized using Hibiscus sabdariffa (Hs) extract are thought to have the potential to be used in both biomedical and catalytic applications. The use of Pt@Ag NPs in the hydrogen production process shows great promise for green energy studies because it is environmentally friendly, non-toxic, and low cost. [Display omitted] • The catalytic activity of Pt-based Ag NPs as a green catalyst was determined. • The hydrogen generation of Pt@Ag NPs was examined on NaBH 4 hydrolysis. • TOF and Ea values of Pt@Ag NPs were found to be 702.38 h−1, 32.48 kJ/mol. • The reusability of Pt@Ag NPs was determined to have an efficiency of 85%. • The rate of produced H 2 depending on the catalyst-substrate-temperature parameters. [ABSTRACT FROM AUTHOR]

In a batch reactor, 0.01 mol/L arginine, lysine, or histidine, which are natural basic amino acids, was used as an environmentally friendly, “green”, catalyst to isomerize 0.2 mol/L ribose to the corresponding ketose, ribulose, at 110 °C. The changes over time in the conversion of ribose, the yield of ribulose, pH, and the absorbance of the reaction mixture at 280 and 420 nm were measured. The yield of ribulose was highest (ca. 8.5 %) when arginine was used as a catalyst, followed by lysine. Ribulose was also produced with histidine, but the yield was very low (ca. 1.5 %). On the other hand, the coloration, which was evaluated by the absorbance of the reaction mixture at 280 and 420 nm, was highest when lysine was used, followed by arginine. Therefore, arginine was the most suitable green catalyst for isomerizing ribose to ribulose among the three basic amino acids tested. [ABSTRACT FROM AUTHOR]

In this study, seven types of α-hydroxycarboxylic acids were selected to form composite catalysts with boric acid, and their catalytic properties were studied using the catalytic hydration of α-pinene. The results showed that the composite catalyst of boric acid and tartaric acid had the highest catalytic activity. With an α-pinene, water, acetic acid, tartaric acid, and boric acid mass ratio of 10:10:25:0.5:0.4, the reaction temperature was 60 °C, the reaction time was 24 h, the conversion of α-pinene was 96.1%, and the selectivity of terpineol was 58.7%. The composite catalyst composed of boric acid and mandelic acid directly catalyzed the hydration of α-pinene in the absence of a solvent. Under the optimal conditions, the conversion of α-pinene reached 96.1%, and the selectivity of terpineol was 55.5%. When the composite catalyst catalyzed α-pinene to synthesize terpineol in one step, the terpineol was optically active, and terpineol synthesized using the two-step method with the dehydration of p-menthane-1,8-diol monohydrate was racemic. These composite catalysts may offer good application prospects in the synthesis of terpineol. [ABSTRACT FROM AUTHOR]

Nitrogen-containing heterocycles have been extensively studied due to their broad biological and pharmaceutical applications. In this study, we synthesized five- and six-membered nitrogen-containing rings through one-pot multicomponent reaction using an aluminium-doped cobalt ferrite nano-catalyst. The nano-catalyst was prepared by the co-precipitation method from the corresponding metal salts. The obtained results show that the proposed catalyst has a high efficiency and has enabled the formation of the desired products with high efficiency and purity. In addition, simplicity of operation, facile purification of products, shorter reaction times, mild reaction conditions, easy separation and recyclability of the catalyst, are the main advantages of this catalyst.

Carbon sphere (CS) was successfully synthesized by using starch via hydrothermal process with optimization of all conditions and parameters, systematically. The optimized CS was modified and used as a catalyst in the dehydrogenation of sodium borohydride in methanol for hydrogen production. Factors affecting the H2 production rate such as reaction temperature, catalyst type and amount, NaBH4 amount were investigated. Activation parameters for the dehydrogenation reaction of NaBH4 with the use of amine modified and protonated CS (H-EDA-CS) catalyst were calculated to be 26.14 kJ.mol−1, 23.75 kJ.mol−1, −192.19 J.mol−1.K−1, for Ea, ΔH# and ΔS#, respectively. Maximum HGR value was calculated as 3460 mL.min−1.g−1 at 25 °C. Moreover, reusability studies of the H-EDA-CS catalyst were made and the activity of the catalyst was found to be above 50% even after the 7th use. The catalyst was also regenerated 3 times, and the % activity results for initial use, 1st, 2nd and 3rd regeneration were calculated as 100%, 91%, 80% and 79%, respectively.

In this paper, the chitosan-functionalized ionic liquid is modified with superparamagnetic iron oxide nanoparticles to form a novel and reusable catalyst (SPION@CS-IL), which was carried out using an ultrasonic promoted approach. Transmission electron microscopy (TEM), vibrating-sample magnetometer (VSM), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and thermogravimetric analysis (TGA) are some of the techniques that are used to fully characterize SPION@CS-IL. The created nanoparticles were discovered to be a reusable heterogeneous superparamagnetic catalyst for the environmentally friendly one-pot synthesis of pyrido[2,3-d]pyrimidine derivatives using a simple three-component reaction approach involving thiobarbituric acid, 4-hydroxy coumarin, and various aromatic aldehydes. The method is studied by performing the reaction under ultrasonic irradiation, while the approach is a "green" method, it uses water as the solvent. The isolated yields of the synthesized products are very advantageous. The catalyst has outstanding reusability and is easily removed from the products via filtration (5 runs). Short reaction times, low catalyst loadings, the nanocatalyst's capacity to be recycled five times, and the absence of harmful chemical reagents are all significant benefits of this environmentally benign process. [ABSTRACT FROM AUTHOR]

Citric acid was discovered as an efficient catalyst for the rapid synthesis of pharmacologically important isoniazid azomethines by condensation of aromatic aldehydes and isatins with isoniazid in aqueous ethanol under reflux condition. The advantages of the described method include the use of readily available starting materials, biodegradable greener catalyst, and mild reaction conditions. The products were obtained in high yield within short reaction time and no need for column chromatography purification. [ABSTRACT FROM AUTHOR]

In this study, activated carbon (AC) was prepared from pistachio nut shell precursor as agricultural by-product. The prepared AC was used to synthesize an efficient nanocomposite via loading of the copper metal and magnetic nanoparticles (Cu-MACαC4H8SO3H NCs) onto its structure. The structure of the nanocatalyst was characterized by different methods such as FT-IR, TEM, EDS, XRD, VSM, and TGA analysis. The catalytic activity of the prepared composite was tested in a special C-S coupling, namely with the reaction of 2-mercapto-3-phenylquinazolin-4(3H)-one with iodobenzene or bromobenzene. The products of the aryl thioquinazoline derivatives were obtained in good yields and in short reaction times and the products were characterized with ¹H, 13C NMR and CHNS analysis. On the other hand, with easy and high recovery of Cu-MACαC4H8SO3H NCs through magnetic separation, a simple and green method to enhance the efficiency of the nanocatalyst has been provided. The nanocatalyst was reused in the next reaction in up to five cycles without obvious activity decrease. [ABSTRACT FROM AUTHOR]

New nanocomposites containing zirconium were synthesized using microwave irradiation. Their structure was confirmed by vibrating sample magnetometer (VSM) curves, X-ray diffraction (XRD) patterns, scanning electron microscope (SEM) and transmission electron microscopy (TEM) images, Fourier transform infrared spectroscopy (FT-IR), and Brunauer–Emmett–Teller (BET) N2 adsorption/desorption isotherms. After the structure confirmation of the zirconium magnetic nanocomposite, the catalytic properties in the synthesis of pyrazole derivatives were investigated. Next, the biological activities of the zirconium magnetic nanocomposite, such as the antibacterial and antifungal activities, were investigated. The research results showed that the zirconium magnetic nanocomposite has high catalytic properties and can be used as a magnetic nanocatalyst for synthesizing heterocyclic compounds such as pyrazole derivatives in addition to having high biological properties. The unique properties of the nanoparticles can be attributed to their synthesis method and microwave radiation. [ABSTRACT FROM AUTHOR]

Microwave irradiation has been used to enhance the reaction yields and selectivities for organic transformation. In this paper, microwave irradiation (MW) was investigated for the environmentally benign synthesis of benzoxazoles through the cyclization of 2-aminophenols and benzaldehydes using deep eutectic solvent (DES) as a catalyst. The [CholineCl][oxalic acid] was easily synthesized from choline chloride with oxalic acid and used without further purification. [CholineCl][oxalic acid] catalyzed the synthesis of benzoxazoles to produce the desired product in a good to excellent conversion and selectivity under MW irradiation. The presence of [CholineCl][oxalic acid] helps to promote the rapid heating transfer from microwave irradiation into the reaction mixture. The [CholineCl][oxalic acid] can be recovered and reused several times without a considerable degradation in catalytic activity. [ABSTRACT FROM AUTHOR]