Efficient Green Catalyst Research Articles

Insilico and Biological Evaluation of Anti-Inflammatory Activity of synthesized Benzimidazoles Derivatives

ABSTRACT: We have developed a mild, easy, and highly efficient green catalyst for the synthesis of 2-substituted benzimidazole. In this study, Ace-dock and DockThore performed molecular docking of the designed benzimidazole molecules with the selected protein FAAH (PDB ID: 3LJ7). We assessed the drug's likeliness (Lipinski's rule of 5) and potential toxicity using the Protox-II software. We can confidently state that the synthesized molecules adhere to Lipinski's rule of five, given that the design molecules' properties are within acceptable limits. In comparison to the reference Ibuprofen, the proposed compounds exhibited favorable pharmacokinetic properties and achieved docking scores ranging from -10.88 to -27.31 (Acedock) and -6.045 to 9.122 (DockThore). We synthesized the benzimidazole derivatives 3a to 3g. Based on an in silico study, we synthesized the molecules, chose the best ones, and then tested their anti-inflammatory action in a lab setting. We employed the albumin denaturation assay test to determine the extent of heat-induced protein denaturation inhibition. Both of the synthesized compounds and the standard drug, diclofenac sodium, inhibit denaturation of proteins at concentrations between 10 and 50 ppm. At a dose of 10 ppm, compound 3f showed the highest level of inhibition, at 70%. Diclofenac sodium exhibited the highest suppression, measuring 97.20% at a concentration of 40 ppm. We could further investigate 3F to determine its anti-inflammatory characteristics.

Humin-sulfuric acid as a novel recoverable biocatalyst for pyrrole synthesis in water

Humin-sulfuric acid (Humin-SO3H) as a novel efficient biobased sulfonic acid was easily prepared by adding chlorosulfuric acid (ClSO3H) to Humin and characterized by potentiometric titration and FT-IR spectrum. Humin-SO3H is an eco-friendly, heterogeneous biobased, and efficient catalyst for Paal-Knorr and Clauson-Kaas pyrrole synthesis. The catalyst is easily recovered by simple filtration and has excellent turnover efficiency even after 4 cycles. Besides, due to the clearance of the biocatalyst away from the reaction media, the desired highly pure products can be achieved in high to excellent yields. Due to high water dispersibility, Humin-SO3H can be utilized as a highly efficient green catalyst for pyrrole synthesis.

A high-throughput screening of catalyst for efficient nitrogen fixation: Transition metal single-atom anchored on an emerging synthesized biphenyl network

Synthesizing efficient and selective green ideal catalysts has been an increasingly critical, yet unsolved, issue for the ammonia synthesis industry, hindering the growing global demand for environmental protection and energy efficiency. Electrocatalytic nitrogen reduction reaction (eNRR) is a promising technology for low-energy ammonia synthesis. However, designing efficient electrocatalysts for NRR remains challenging. The emergence of graphene-like substrates offers exciting prospects for addressing this challenge and facilitating single-atom catalysts in eNRR. Here, we report the innovative selection of a recently synthesized two-dimensional biphenyl network (2D BPN) compound as a substrate. Its excellent conductivity and porosity enable stable transition metal atoms (TMs) support for constructing eNRR electrocatalysts. we evaluated the feasibility of 23 TMs anchored on BPN for eNRR by high-throughput first-principles calculations. Through a systematic five-step strategy, we identified several single-atom catalysts (SACs) with potential for eNRR, including Mo@BPN, V@BPN, W@BPN, and Re@BPN. Among them, Mo@BPN exhibited the best balance in the adsorption of key reaction intermediates (e.g., N2H and NH3) and demonstrated a low limiting potential (-0.37 V). In addition, the underlying mechanism of NRR activity was elucidated by analyzing the extrinsic patterns revealed through the screened catalysts. A triangular volcano diagram, incorporating the initial protonation step, adsorption free energy, and final protonation step, revealed the NRR activity trend. Overall, this study provides a solid theoretical foundation and valuable guidance for future experimental exploration of efficient electrocatalysts for ammonia synthesis on BPN. Crucial insights into the theoretical design of efficient electrocatalysts are also offered.

Orange Juice: A Remarkable Green Catalyst for the Michael Addition Reaction of Indoles

Michael addition reaction is widely accepted as the most important reaction for making carbon-carbon bonds in the synthesis of organic compounds. In this reaction, an enone is attacked by a nucleophile in a conjugated manner across a carbon-carbon double bond. The present work reported the Michael reaction of indole with α,β-unsaturated ketones via alkylation to yield 3-(3-oxoalkyl) indole or β-indolyl ketones. Naturally available orange juice has been demonstrated to be an efficient green catalyst for the Michael addition reaction of indoles with various cyclic and acyclic unsaturated ketones. The products were characterised by 1H NMR spectroscopy and compared with literature. This one-step, simple process has afforded the 3-indolyl carbonyl compounds in short reaction times and excellent yields at room temperature. The present method developed an inexpensive synthetic process to prepare substituted indoles in a simple and eco-friendly way.

Activation of calcium sulfite by bismuth cobalt-copper perovskite-manganese dioxide composite for efficient degradation of metronidazole

The highly efficient BiCo0.5Cu0.5O3-MnO2 catalyst was prepared using the hydrothermal method and utilized for the first time to activate sulfite for degrading metronidazole (MNZ) in this study. Physicochemical analysis of the BiCo0.5Cu0.5O3-MnO2 catalyst was performed using XRD, FTIR, BET, SEM, TEM, and XPS, confirming the successful synthesis of catalyst. BiCo0.5Cu0.5O3-MnO2 demonstrated a larger specific surface area, a more uniform pore structure, and prevented perovskite agglomeration. The catalyst effectively activated CaSO3, resulting in the degradation of 99.94 % of MNZ within 30 min, showing excellent catalytic performance. Quenching experiments and EPR tests indicated that SO•-4, SO•-5 and 1O2 were the main reactive species, with the oxygen vacancy on the catalyst surface playing a crucial role in accelerating the formation of reactive species and electron transfer. Moreover, the valence transformation of Co, Cu, and Mn was identified as the main contributor to the activation of CaSO3, demonstrating significant synergistic effects. Liquid chromatography-mass spectrometry detected eleven intermediates, revealing that the BiCo0.5Cu0.5O3-MnO2/CaSO3 system could convert MNZ into low-toxicity products through three potential degradation pathways. Density functional theory (DFT) calculations showed that higher Fukui indices of MNZ sites were more susceptible to free radical attack. The BiCo0.5Cu0.5O3-MnO2/CaSO3 system also exhibited excellent degradability to different natural water bodies and other pollutants. Furthermore, the catalyst displayed strong stability and outstanding catalytic performance after 5 cycles. This study presents a versatile strategy for developing highly efficient green catalysts, which could be utilized in organic wastewater treatment.

Synthesis of environmental benign biodiesel from algal (Anabaena) oil using Ba2SiO4 as efficient green catalyst

The current work demonstrates a simple solid-state method for producing barium silicate catalyst for transesterification of Anabaena oil. The designed Ba2SiO4 spinel catalyst was characterised by following techniques such as thermo gravimetric analysis (TGA-DSC), powder X ray diffraction (P-XRD), furrier transfer infrared spectroscopy (FT-IR), scanning electron microscopy and electron diffraction spectroscopy (SEM-EDX), BET-surface area analyser and Hammett indictor acid-base titration method. The optimum condition for achieving highest FAME conversion of 98.4 % was observed at 65 °C, 12:1 methanol to oil molar ratio at 4h of reaction time. The catalyst was also stable up to six cycles with 98.1 % FAME conversion. Fuel properties of synthesized biodiesel were also compared with the ASTM standard. Kinetics studies revealed that transesterification of Anabaena oil is compactable with pseudo first order model with comparable activation energy 36.48 kJ/mol. The reaction equilibrium constants were also studied in the temperature range of 45°–65 °C and the standard thermodynamic properties like ΔH# = 98.73 kJ mol−1, ΔG# = 23.53 kJ mol−1, ΔS# = 0.864 kJ mol−1 were obtained at 65 °C.

DFT study of N-modified graphene-loaded monometallic cobalt for acetylene hydrochlorination reaction

The density functional theory (DFT) was used to systematically investigate the effects of non-precious metal catalysts doped with different numbers of N atoms, graphene-CoNx (x = 1,2,3,4), on reaction mechanism of acetylene hydrochlorination reaction. It was found that three graphene-CoNx (x = 1,2,3) catalysts can activate C2H2 and HCl and absorb them on their surface. The electron transfer between the metal atom and the N and C atoms attached to it can be used as a descriptor of catalytic properties. Moreover, the catalytic activity of graphene-CoNx (x = 1,2,3) decreased with the decrease in the number of N atoms. One of the graphene-CoN3 catalysts has the lowest reaction energy barrier of 0.77 eV free energy. This work reveals the local coordination environment of N-doped graphene-loaded single-atom Co-catalyzed acetylene plus hydrogen chloride, which provides a theoretical basis for the design of efficient green catalysts.

Mechanism of Pechmann condensation reaction – A quantum mechanical case study with choline-based ionic liquid

At present, many researchers are aiming to develop an efficient and re-usable green catalyst for industrially relevant chemical reactions. Particularly, Pechmann condensation reaction is an important reaction that is used to prepare Coumarin derivatives which find applications in biology and medicine. In this regard, choline based ionic liquids (CILs) are reckoned as effective eco-friendly catalysts for many organic transformations. Specifically, N,N-dimethylaminoethanol [N112OH][HSO4] (NS-CIL) was found to be the effective catalyst for promoting Pechmann condensation in an efficient manner. The present work demonstrates the detailed mechanistic investigation on the three possible pathways (A, B and C) of Pechmann condensation using NS-CIL as catalyst [RSC Adv, 2014, 4, 22946–22950]. Our computed results reveal that the pathway B which involves Electrophilic attack → Water-elimination → Trans-esterification (EWT – Route) is both thermodynamically and kinetically most favourable pathway with a relatively small activation energy of 20.23 kcal/mol at the rate-determining step. Further, NS-CIL has been identified to be a vital entity in decreasing the activation barriers by acting as proton-shuttle and in stabilizing the intermediates and transition states with weak intermolecular hydrogen bonding interactions via most-acidic N–H and O–H protons of cationic unit of NS-CIL. Thus, the mechanistic insights gained through this work will aid and impel the development of more efficient ionic liquid based green catalysts for Pechmann condensation reaction and similar other industrially important reactions.

Boric Acid: A Mild and Efficient Green Catalyst for Organic Transformations

Abstract

Recyclable copper-decorated magnetic composites as non-precious catalysts for effective removal of 4-nitrophenol and azo dyes

Carbonized lotus leaf (CLL) from agricultural waste is employed as the support to prepare the novel Cu-Fe3O4/carbonized lotus leaf (CuX-FCLL) catalysts. The magnetic catalyst Cu1.5-FCLL demonstrated desirable catalytic activity for the reduction of organic dyes (Congo red, Methyl orange) and nitroaromatic compounds (3- and 4-nitrophenols). The magnetically recoverable catalyst (Cu1.5-FCLL) exhibited ultrafast catalytic activity for 4-nitrophenol reduction with a conversion rate of over 98% within 30 s, which was comparable to those noble metal catalysts widely used. The CLL with unique papillae structures could provide large surface areas and prevent aggregation of metal NPs, and boost the catalytic performance of Cu1.5-FCLL by a synergetic effect. Such a magnetic catalyst was facilely recovered and reused after ten cycles with negligible loss of catalytic performance. This work presents an efficient green catalyst to replace noble metals for wastewater treatment.

Carbon spheres as an efficient green catalysts for dehydrogenation of sodium borohydride in methanol

Carbon spheres as an efficient green catalysts for dehydrogenation of sodium borohydride in methanol

Karanja seed shell ash: A sustainable green heterogeneous catalyst for biodiesel production

In the present study, the ash from discarded Karanja seed shell (KSS), obtained after burning dried seed shells has been identified as one of the most cost-effective and efficient green heterogeneous catalysts for biodiesel production. Soybean oil methanolsis was used to study the catalytic activity of karanja seed shell ash as solid base heterogeneous catalysts in the biodiesel production. To characterize the catalyst, XRD, WD-XRF, SEM, FT-IR, BET and TGA techniques were utilized. Soybean oil methyl ester was converted under the following experimental conditions, as determined by GC-MS, and FT-IR: a catalyst amount of 2 wt%, a methanol to oil molar ratio of 10:1, a reaction temperature of 65 °C, a reaction time of 60 min. The synthesized heterogeneous catalyst is an efficient alternative that may be utilized as an eco-friendly catalyst because it is benign, reusable, sustainable, and widely available.

β-FeOOH/TiO2/cellulose nanocomposite aerogel as a novel heterogeneous photocatalyst for highly efficient photo-Fenton degradation.

The photo-Fenton reaction provides an effective strategy for the removal of organic pollution in water environments. However, it remains a great challenge to develop photo-Fenton catalysts with high photocatalytic activity, low catalyst losses and excellent recyclability. In this work, a β-FeOOH/TiO2/cellulose nanocomposite aerogel was fabricated as an efficient and convenient heterogeneous catalyst in the photo-Fenton system via in situ synthesis of TiO2 and β-FeOOH NPs on a cellulose-based aerogel. The cellulose aerogel not only acted as a microreactor to prevent aggregation of particles, but also acted as a supporting material to improve the stability and reusable performance of the catalyst. Meanwhile, the synergy between TiO2 and β-FeOOH endowed the cellulose-based nanocomposite aerogel with highly efficient photo-Fenton degradation of dyes. As a result, the composite β-FeOOH/TiO2/cellulose aerogel displayed high photocatalytic performance. Its removal efficiency of MB reached 97.2% under weak UV light for 65 min. There is no obvious decrease in the catalytic efficiency after 5 cycles, suggesting the stability and recyclability of the composite aerogel. This study provides a novel strategy for the preparation of efficient green heterogeneous catalysts by using renewable resources, and shows composite catalyst processes have great potential in wastewater treatment.

AlCl3@ZnO nanostructured material: an efficient green catalyst for the one-pot solvent-free synthesis of 1,4-dihydropyridines.

AlCl3-loaded ZnO nanoparticles have been explored as an efficient catalyst for 1,4-dihydropyridine synthesis under ambient temperature and solvent-free conditions. For this purpose, ZnO nanoparticles were synthesized by a simple solution-based precipitation technique using a stoichiometric amount of zinc sulfate and oxalic acid. The AlCl3@ZnO nanocrystalline catalyst was prepared by loading 20% AlCl3 on ZnO nanoparticles by a simple wet-impregnation technique. This catalyst efficiently performed Hantzsch pyridine reactions with various aromatic aldehydes, ethyl acetoacetate and ammonium acetate. The nanostructured AlCl3-loaded ZnO catalyst was characterized by UV-DRS, XRD, FESEM, EDS, FETEM-STEM-EDS and XPS techniques. The comprehensive characterization reveals the formation of AlCl3-loaded ZnO catalysts with an average particle size of 70-80 nm. The loading of AlCl3 on the ZnO surface was confirmed by minor shifts in the XPS and XRD peaks. FETEM-STEM-EDS also indicates reasonable AlCl3 loading on ZnO nanoparticles. The 20% AlCl3-loaded ZnO nanocatalyst (AlCl3@ZnO) confers 92% yield for the synthesis of 1,4-dihydropyridine under solvent-free and ambient temperature conditions. The synthesized 1,4-dihydropyridines were characterized by 1H-NMR, 13C-NMR, HRMS and FT-IR spectroscopic techniques. The reported catalyst is highly efficient, environmentally friendly and could become an alternative to homogenous and heterogenous catalytic reactions.

Embedding Double Transition Metal Atoms in B-Modified Two-Dimensional Carbon-Rich Conjugated Frameworks for Efficient Ammonia Synthesis.

It is important to develop an efficient green catalyst for electrochemical nitrogen reduction under environmental conditions to replace the Haber-Bosch process with high energy consumption, limited economic scale of production, and high CO2 emissions, but there are still some difficulties in its development and design. In this work, based on 2D CCFs, a B-modified rectangular-shaped expanded phthalocyanine bimetallic atomic catalyst is proposed. Because both the TM-d orbital and the B-sp3 hybrid orbital can accept the lone pair and feedback electrons of N2, and there are significantly different valence electron distributions between the two different metals and boron, this catalyst not only keep the advantages of metal catalysts but also play the role of the B atom to further increase the polarity of nitrogen and activate N2. In order to evaluate the catalytic performance of this catalyst, its stability, activity, selectivity, reactivity, and other aspects are screened and analyzed by density functional theory calculation. Among them, the FeNb-BPc CCF catalyst has better N2 adsorption capacity under ambient conditions, exhibits excellent catalytic activity through a continuous mechanism, and has a lower limiting potential of -0.24 V. We believe that this work opens a new path for the rational design of efficient N2 reduction reaction catalysts and also provides a theoretical basis for experimental development.

Basic ionic liquid grafted on magnetic nanoparticles: An efficient and highly active recyclable catalyst for the synthesis of β-nitroalcohols and 4H-benzo[b]pyrans

In this study, we have synthesized Fe3O4@SiO2 (FS) immobilized 1,4-diazabicyclo[2.2.2] octane (DABCO) based-basic ionic liquid functionalized magnetic nanoparticles. The synthesized nanocomposite was characterized by various physicochemical and morphological techniques such as - FTIR, Powder-XRD, VSM, BET, CHN, TEM and SEM-EDX. Its application was checked as an active and highly efficient green catalyst by utilizing it in the synthesis of various 4H-benzo[b]pyran and β-nitroalcohol derivatives. The prepared heterogeneous catalyst was found to be thermally stable and highly cost-effective for the base-promoted organic transformation reactions producing excellent yields in short reaction times. In addition to this, the prepared magnetic nanocomposite could be readily recovered by applying a magnetic field and can be recycled up to eight catalytic cycles without any noteworthy loss in its performance.

Montmorillonite K10 Clay Catalyzed Synthesis of Novel β-Aminocarbonyl Compounds and Their Biological Evaluation.

An efficient and reusable green catalyst for the synthesis of β-aminocarbonyl compounds has been developed. In this new and greener approach, β-aminocarbonyl compounds (1a-1r) were obtained by Montmorillonite K10 clay catalyzed reaction of aryl amines, aliphatic/aromatic aldehydes and β-ketoesters. Molecular docking investigations were performed for all compounds (1a-1r) with the proteins PDB ID: 1JIJ and 1KZN for S. aureus and E. coli, respectively. For all compounds good to strong interactions with the active sites were observed. The biological activities of β-aminocarbonyl compounds were further assessed for their antibacterial and antioxidant activities. The results confirmed that β-aminocarbonyl compounds could be further developed into new drugs with potent antibacterial and antioxidant activities.

MOF-253 immobilized Pd and Cu as recyclable and efficient green catalysts for Sonogashira reaction

MOF-253·Pd(OAc) 2 and MOF-253·CuI were prepared, characterized, and evaluated firstly as heterogeneous co-catalysts, which showed high catalytic activity in Sonogashira coupling reaction of various substituted (hetero)aryl halides with terminal alkynes at 70–120 °C, and afforded the corresponding products in 45–99% yields with high TON (∼2722 for Pd). The best result was achieved with an extremely low Pd (0.036 mol%) and Cu (0.397 mol%) loading. Moreover, the catalysts can be reused at least five times without significantly reducing the activity. Besides, Hg(0) and PVP-poisoning experiments confirmed that the present catalysts were efficient and heterogeneous catalysts in this coupling reaction.

A facile one-pot synthesis, computational and molecular docking studies of benzimidazole and benzothiazole compounds using Amberlite IRA 400-Cl resin as green/reusable catalyst

A series of pharmaceutically valuable, functionalized fused heteroaromatic compounds such as benzimidazoles, and benzothiazoles have been synthesized via catalytic cyclocondensation between o-phenylenediamine, or o-aminothiophenol, and aryl aldehydes at ambient conditions. The Amberlite IRA400-Cl anionic resin has proved to be an efficient green catalyst in this protocol. The salient features of this method are the mild condition, easy work-up, an excellent yield of product, green catalyst, and reusability of the catalyst. Theoretical studies on selected compounds have been carried out using Density Functional Theory (DFT) method and Gaussian 09 package, B3LYP 6-311G(d,p) basis set. Molecular docking studies were also performed on selected compounds to determine their pharmaceutical activities.

Cu/nucleotide coordination self-assembling to in situ regenerate NAD(P)+ and co-immobilize dehydrogenase with robust activity and stability

Enzyme is an efficient green catalyst, but its vulnerability and difficulties of separation from products limited the application in industry. Furthermore, a large number of oxidase enzymes rely on dihydronicotinamide adenine dinucleotide (NADH) or dihydronicotinamide adenine dinucleotide phosphate (NADPH) cofactors. These cofactors are too expensive to be used in industrial processes. Thus, cofactor regeneration is an important method to avoid the consumption of large quantities of oxidized cofactor NAD(P)+ in enzyme-catalyzed reactions. In this paper, Cu based metal nucleotides coordination polymers (MNCPs) with NAD(P)H oxidase activity were constructed by self-assembly of copper ions and nucleotides. Cu2+/AMP and Cu2+/GMP showed high catalytic activity and high reusability. Then, Cu2+/AMP with NADH oxidase activity was combined with NAD+ dependent alcohol dehydrogenase (ADH) to construct a bienzyme cascade system with circulating cofactor, which applied to the conversion of benzyl alcohol to benzaldehyde. In this system, ADH exhibited high activity due to the increase of substrate concentration and the inhibition of the diffusion of intermediate products. Besides, the bienzyme cascade system also showed high stability and reusability. After 8 cycles, the immobilized ADH remained more than 57% of the initial activity. The prepared bienzyme cascade system can extensively extended its application in industrial production.