Heterogeneous Catalyst For Green Synthesis Research Articles

Novel heterogeneous catalyst for green synthesis of imidazole derivatives: environmental sustainability metrics assessment

Novel heterogeneous catalyst for green synthesis of imidazole derivatives: environmental sustainability metrics assessment

Pyromellitic acid grafted to cross-linked LDH by dendritic units: An efficient and recyclable heterogeneous catalyst for green synthesis of 2,3-dihydro quinazoline and dihydropyrimidinones derivatives

In this work, using layered double hydroxide (LDH) inorganic substrate, melamine as binding agent and dendrimer G1 and also pyromellitic acid (PMA) organic catalytic agent a heterogeneous acid catalyst was designed and prepared. After that, the prepared organic-inorganic catalyst was evaluated by various identification techniques such as FTIR, EDX, XRD, TGA, FESEM, and BET, and the results showed that the desired structure was successfully prepared. Also, in order to investigate the efficiency of the LDH@Me-PMA nanocatalyst as an efficient and heterogeneous catalyst, it was used for green and one-pot synthesis of 2,3-dihydro quinazoline and 3,4-dihydropyrimidinone-2-(1H)-ones derivatives. The use of LDH@Me-PMA catalyst led to the synthesis of the desired derivatives with higher efficiency and shorter reaction time than previously reported works. In addition, the prepared LDH@Me-PMA acid catalyst has the ability to be recycled and reused for 5 consecutive periods and has high stability, which is well consistent with the principles of green chemistry.

MNP-cellulose-OSO3H as an efficient and biodegradable heterogeneous catalyst for green synthesis of trisubstituted imidazoles.

Cellulose is an eco-friendly, efficient, and suitable substrate for use as a coating material and support in the preparation of catalysts. Herein, MNP–cellulose–OSO3H was prepared as an efficient heterogeneous catalyst composed of Fe3O4 nanoparticles covered with cellulose–OSO3H and used for the synthesis of trisubstituted imidazoles. The catalyst was characterized by FT-IR, CHNS, ICP, PXRD, EDAX, elemental mapping, SEM, TEM, zeta potential, TGA, and VSM techniques. The catalytic activity was evaluated in the one-pot three-component synthesis of trisubstituted imidazole derivatives using benzil or 9,10-phenanthrenequinone, different aldehydes, and ammonium acetate in EtOH solvent at 80 °C over 30 min. The yields of products were excellent, in the range 83–97%. The catalyst showed outstanding catalytic performance toward heating conditions and good reusability. Also, this methodology had several advantages, such as simple procedures, short reaction time, excellent yield, simple workup, and mild reaction conditions.

L-(+)-Tryptophan methyl ester derived polymeric microbeads as an efficient heterogeneous catalyst for green synthesis of 2-amino-4-(nitromethyl)-4H-chromene-3-carbonitriles.

The cross-linked microbeads with average diameter of 106-300 μm, [poly(EGDMA-MATrp)], were obtained by copolymerization reaction of N-methacryloyl-L-(+)-tryptophan methyl ester (MATrp) with ethylene glycol dimethacrylate (EGDMA) and successfully applied as a heterogeneous catalyst in conjugate addition reaction of nitromethane to substituted 2-iminochromenes in aqueous media. A variety of 2-amino-4-(nitromethyl)-4H-chromene-3-carbonitriles has been synthesized in good yields. Polymeric microbeads were very durable and reused 5 times without a significant loss of activity. DFT calculations and experimental results revealed the significant role of π-π interactions as well as hydrogen bonding in the reaction mechanism.

Dinuclear Copper Complex Immobilized on a Janus-Type Material as an Interfacial Heterogeneous Catalyst for Green Synthesis.

We herein describe a rational design of a heterogeneous catalyst composed of a dinuclear cuprate anion being immobilized electrostatically on one surface of Janus-type nanosheets while the other surface is decorated with highly hydrophobic octyl groups. The catalyst was found to be well dispersible in the organic phase of a biphasic aqueous/organic mixture. It was characterized by means of elemental analysis, atomic absorption spectroscopy, mass spectrometry, N2 absorption-desorption analysis, thermogravimetric analysis, scanning electron microscopy (SEM), and solid-state 13C and 29Si cross-polarization magic-angle spinning nuclear magnetic resonance spectroscopy. The Janus nature of the catalyst was investigated by employing a selective surface labeling method and by means of SEM. The catalyst shows higher activity compared to a non-Janus analogue in a biphasic synthesis. It was successfully used for the azide-alkyne cycloaddition and the Chan-Lam C-N coupling reaction. In addition, new and simple ways have been established for the production of a coumarin-triazole derivative and for the synthesis of the biologically active compound Monastrol via a solvent-free Biginelli reaction. The role of the dinuclear copper centers is discussed mechanistically.

KF/Clinoptilolite Nanoparticles as a Heterogeneous Catalyst for Green Synthesis of pyrido[2,1-a]isoquinolines using Four-Component Reaction of Alkyl Bromides.

KF/Clinoptilolite nanoparticles are employed as a heterogeneous catalyst for the preparation of pyrido[2,1-a]isoquinoline derivatives through a four-component reaction of isoquinoline, two different alkyl bromides and an electron deficient internal alkynes at ambient temperature in water as green solvent. In this research, (2,2-Diphenyl-1-picrylhydrazyl) radical trapping and reducing potential of ferric ion experiments was used for determining antioxidant activity of some newly synthesized compounds such as 5a, 5c, 5f and 5g and comparing results with synthetic antioxidants (TBHQ and BHT). Compounds 5a, 5c, 5f and 5g display trace DPPH radical trapping and excellent reducing power of ferric ion. Furthermore, the power of some prepared compounds against Gram-positive and Gram-negative bacteria was proved by employing the disk dispersion experiment. The obtained results of disk diffusion test showed that compounds 5a, 5d and 5e prevented the bacterial growth. The reported procedure shows the advantages of clean reaction, high yield and simple purification.

Silver phosphate supported on metal–organic framework (Ag3PO4@MOF‐5) as a novel heterogeneous catalyst for green synthesis of indenoquinolinediones

A new Ag3PO4@MOF‐5 catalyst has been synthesized and successfully applied in the green synthesis of a library of indenoquinolinediones via one‐pot, multi‐component reaction of aldehyde, indanedione and enaminone under solvent‐free conditions at room temperature. The catalyst was characterized using various spectroscopic techniques and elemental analysis. The catalyst can be easily separated and exhibits significant recyclability, with insignificant loss of activity after four consecutive runs. The protocol presented has advantages like green reaction conditions, high yield of products, no need for column chromatography and good recyclability.

Synthesis and characterization of sodium polyaspartate‐functionalized silica‐coated magnetite nanoparticles: A heterogeneous, reusable and magnetically separable catalyst for the solvent‐free synthesis of 2‐amino‐4H‐chromene derivatives

An efficient and facile method was used for the synthesis of sodium polyaspartate‐functionalized silica‐coated magnetite nanoparticles. The structure of this nanoparticle was characterized by scanning electron microscopies, X‐ray diffraction, energy‐dispersive X‐ray, Fourier transform infrared spectroscopies and vibrating sample magnetometry. Then, this compound was used as a reusable heterogeneous catalyst for green synthesis of 2‐amino‐4H‐chromene derivatives via one‐pot three‐component reactions. This novel material showed great catalytic performance and the reactions which were carried out by this catalyst showed good to excellent yields. Besides, the catalyst could easily be separated from the reaction mixture by using an external magnetic field and it was stable enough to reuse several times without any significant reduction in the yield of reactions. Eco‐friendliness, high purity of the desired products, short reaction time and easy workup procedure can be mentioned as the other advantages of this method.

Functionalized multi-walled carbon nanotubes as an efficient reusable heterogeneous catalyst for green synthesis of N-substituted pyrroles in water

In this protocol, the functionalization of multi-walled carbon nanotubes (MWCNTs) was investigated and they were applied as a recyclable heterogeneous catalyst for the synthesis of N-substituted pyrroles.

MnFe2O4@NH2@2AB-Ni: a novel, highly active, stable and magnetically recoverable nanocatalyst and use of this heterogeneous catalyst in green synthesis of spirooxindoles in water

In this research, superparamagnetic manganese ferrite nanoparticles were synthesized following a co-precipitation method, and subsequently coated with 3-aminopropyltriethoxysilane (APTES) through a silanization reaction. Manganese ferrite nanoparticles afforded bidentate ligands as a result of the reaction between isatoic anhydride and amino-functionalized MnFe2O4. The amino-functionalized nanoparticles were treated with nickel acetate, giving the immobilized nickel complex. Finally, catalytic properties of the prepared nanoparticles were examined by a green synthesis of spirooxindoles in water and they showed excellent catalytic activity. Recovery of the catalyst was simply achieved by applying an external permanent magnet. The isolated catalyst was reused for new reaction runs without significant loss of catalytic activity.

Application and characterization of eggshell as a new biodegradable and heterogeneous catalyst in green synthesis of 7,8-dihydro-4H-chromen-5(6H)-ones

An efficient and eco-friendly method for the synthesis of 7,8-dihydro-4H-chromen-5(6H)-ones has been developed by using eggshell as a natural and heterogeneous catalyst. A mixture of an appropriate aldehyde, malononitrile and dimedone in the presence of eggshell at ambient temperature in EtOH resulted in 90–98% yields of the corresponding products. This new and green methodology is of interest due to use of a green, bioactive and biodegradable catalyst, its short reaction time, high yields without further purification and the ability to carry out the large scale reactions. Prepared eggshell was characterized by elemental analysis, infrared spectroscopy, particle size distribution, X-ray diffraction and fluorescence, scanning electron microscope, thermo gravimetric and BET surface area analysis.