Efficient Heterogeneous Catalyst For Synthesis Research Articles

Zinc Oxide Nanoparticles as Efficient Heterogeneous Catalyst for Synthesis of Bio‐active Heterocyclic Compounds

AbstractAmong the most effective recoverable catalytic systems, metal‐oxide nanoparticles (NPs) are well known for their extensive uses in a broad range of industries, pharmaceuticals, and nano‐biotechnology. In addition, heterogeneous catalysis uses clearly defined materials which are present an extensive range of new possibilities for the research and production of innovative catalysts that help to solve the world's energy and environmental problems. ZnO‐NPs have been used as effective nanocatalysts according to the literature for various kinds of organic reactions. The extensive advantages of ZnO‐NPs over bulk materials suggest that this is a promising field for further research. This review article provides an in‐depth overview of the several ZnO‐NPs that have been reported to catalyse organic transformations including the production of bio‐active compounds like benzofuran, coumarin, imidazole, indole, pyrazole, pyridine pyrimidine, thiazole, diazepine, azoles derivatives. Recent synthetic routes for modifying and functionalizing ZnO‐NPs to increase their catalytic efficacy were also addressed, and illustrated with schematics. The development of novel, highly effective, and reusable modified ZnO‐NPs as catalysts, which would clear the way for the establishment of greener and sustainable technologies, provides the key to the future of catalysis. Researchers attempting to synthesise new functionalized ZnO‐NPs for sustainable development will find this review informative.

Sulfonic acid decorated graphene oxide (GO-SO3H): a efficient heterogeneous catalyst for synthesis of tert-butyl/ethylacetate and pyrazole disubstituted tetrazole derivatives

Sulfonic acid decorated graphene oxide (GO-SO3H): a efficient heterogeneous catalyst for synthesis of tert-butyl/ethylacetate and pyrazole disubstituted tetrazole derivatives

Design and characterization of an urea-bridged PMO supporting Cu(II) nanoparticles as highly efficient heterogeneous catalyst for synthesis of tetrazole derivatives

In this work, a new periodic mesoporous organosilica with urea-bridges produced by the reaction of (3-aminopropyl)triethoxysilane and toluene-2,4-diisocyanate (APS-TDU-PMO) is introduced. The obtained APS-TDU-PMO was found to be an appropriate support for loading of Cu(II) nanoparticles to afford supramolecular Cu@APS-TDU-PMO nanocomposite. Uniformity and mesoporosity of both synthesized nanomaterials including APS-TDU-PMO and Cu@APS-TDU-PMO were proved by different spectroscopic, microscopic or analytical techniques including FTIR, EDX, XRD, FESEM, TEM, BET, TGA and DTA. Furthermore, the prepared Cu@APS-TDU-PMO nanomaterial was also used, as a heterogeneous and recyclable catalyst, for the synthesis of tetrazole derivatives through cascade condensation, concerted cycloaddition and tautomerization reactions. Indeed, the main advantages of this Cu@APS-TDU-PMO is its simple preparation and high catalytic activity as well as proper surface area which enable it to work under solvent-free conditions. Also, the introduced Cu@APS-TDU-PMO heterogeneous catalyst showed good stability and reusability for six consecutive runs to address more green chemistry principles.

Basic ionic liquid anchored on UiO-66-NH2 metal–organic framework: a stable and efficient heterogeneous catalyst for synthesis of xanthenes

In this study, the Zr-based metal–organic framework, UiO-66-NH2, was modified with ionic liquid (dibutylimidazolium bromide) to generate a platform for supporting an organocatalyst of guanidine. After an anion exchange, the prepared hybrid system was denoted as UiO-66-NH2-ILPF6–-guanidine. The catalyst was characterized by different techniques such as PXRD, FTIR, TEM, SEM–EDS, TGA, and BET. The basic heterogeneous catalyst was then utilized for the synthesis of xanthene derivatives via a reaction of aldehydes with dimedone. Various types of aromatic aldehydes were employed for the synthesis with medium to high yield. The study of catalytic activities showed that the heterogenization of guanidine significantly promotes catalytic performance in comparison with guanidine in a homogeneous form. The heterogeneous catalyst is stable in the reaction medium and can be recycled for at least four times without significant reduction in activity. The stability of the catalyst was also investigated by XRD, FTIR, SEM/elemental mapping, and leaching test.

Zn/Al/Pb Mixed Oxides as Efficient Heterogeneous Catalysts for the Synthesis of Methyl N-Phenyl Carbamate.

Dimethyl carbonate aminolysis is an effective and green pathway for the synthesis of methyl N-phenyl carbamate (MPC), which is an important intermediate for the synthesis of polyurethanes and many other chemicals. In this work, we demonstrate the fabrication of Zn/Al/Pb mixed oxides as efficient and stable heterogeneous catalysts for MPC synthesis. The catalysts are prepared via facile coprecipitation and subsequent thermal annealing. Their micromorphology and physical–chemical properties are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning TEM (STEM), X-ray photoelectron spectroscopy (XPS), and NH3-TPD. The results show that rather than being doped into ZnO and/or Al2O3, PbO is highly dispersed in the ZnO/Al2O3 base forming ultrafine nanoparticles. Despite the weak interactions within the mixed oxides, the high density of active sites generates outstanding catalytic activity and cycling stability for MPC synthesis, with an aniline conversion of almost 100% and MPC yield of up to 90% during six repeated tests, providing great potential for their further application.

The SO3H-functionalized carbonaceous@montmorillonite efficient heterogeneous catalyst for synthesis of trimethylolpropane from long-chain fatty acid

Abstract As the increasing demand of bio-lubricants in industries, the new “green” synthetic method to polyolesters has attracted lots of attention. Herein, we report a novel efficient heterocatalyst contained sulfonic acid group, which was assembled through hydrothermal carbonization with the mixture carbon source of chitosan and furaldehyde, the hydroxyethylsulfonic acid aqueous solution was added as SO3H source. The obtained carbonaceous intercalated clay composites conserved regular layered and enlarged specific surface areas and pore volumes, which were proved by small-angle XRD, SEM and N2 sorption isotherms. The FT-IR, XPS, 13C CP/MAS NMR spectrum, Raman spectra and elemental analysis were employed to confirm the SO3H groups and its loading level. As an acidic heterogeneous catalyst for esterification between trimethylolpropane and oleic acid, synthesized SO3H-loaded carbonaceous intercalated montmorillonite composite exhibits high catalytic activity under the solvent-free conditions. The yield of the desired bio-lubricant is as high as 91% in 3 h. With little loss of catalytic activity after be reused five times, the SO3H-functionalized carbonaceous intercalated montmorillonite composite shows good reusability.

Zeolitic Imidazolate Frameworks ZIF-8 and MAF-5 as Highly Efficient Heterogeneous Catalysts for Synthesis of 1-Methoxy-2-propanol from Methanol and Propylene Oxide

Herein, we demonstrated that zinc zeolitic imidazolate frameworks (ZIFs) based on 2-methylimidazole (ZIF-8) and 2-ethylimidazole (MAF-5 or ZIF-14) linkers could be used as effective heterogeneous c...

Sulfamic acid well dispersed in the micropores of Al-pillared α-ZrP as efficient heterogeneous catalyst for synthesis of structurally diverse 1,4-dihydropyridines under mild conditions

In this study, α-zirconium phosphate (α-ZrP) has been prepared via reflux method. The α-ZrP material was pillared with [Al13O4(OH)24(H2O)12]7+ polycations to improve its surface area and thermal stability. The aluminum oxyhydroxy clusters were synthesized by in situ partial base hydrolysis of the aluminum salt precursor using sodium hydroxide as base. The microporous inorganic matrix of Al-pillared α-ZrP (AZP) was used for molecular dispersion of sulfamic acid to prepare novel composite materials. The sulfamic acid modified AZP materials were characterized by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET) specific surface area analysis. XRD study indicated an expansion in the interlayer space as a result of bilayer intercalation of Al137+ pillaring species. The pillared interlayer space is retained in the composite material. FTIR study indicated the structural integrity of the sulfamic acid. The composite materials exhibited enhanced microporosity with surface area and pore volume in the range 80–120 m2/g and 0.1–0.2 cc/g. FESEM and HRTEM studies indicated morphological reorganization of α-ZrP particles as a result of pillaring and subsequent dispersion of sulfamic acid. Elemental mapping study suggested well dispersion of the sulfamic acid in the composite material without any sign of local agglomeration. The catalytic activity of sulfamic acid loaded AZP materials has been evaluated for the synthesis of 1,4-dihydropyridines by multi component condensation reaction of ethyl acetoacetate, arylaldehydes/chalones and ammonium acetate. The composite materials were highly active for synthesis of structurally diverse 1,4-dihydropyridines in high yield and purity under mild conditions.

Manganese Incorporated MCM-41 an Efficient Heterogeneous Catalyst for Synthesis of 3,4-Dihydropyridine-2(1H)-Ones Under Solvent Free Conditions

Manganese Incorporated MCM-41 an Efficient Heterogeneous Catalyst for Synthesis of 3,4-Dihydropyridine-2(1H)-Ones Under Solvent Free Conditions

Poly(vinylimidazolum acetic acid)-entrapped nanozeolite: efficient heterogeneous catalyst for synthesis of polyhydroquinolines and 1,4-dihydropyridines

An effective method for synthesis of substituted 1,4-dihydropyridines and polyhydroquinoline derivatives by Hantzsch reaction using poly(ionic liquid)-based nanozeolite (NZ@PIL-COOH) catalyst under simple conditions is described. The new solid acid catalyst was prepared by polymerization of 3-carboxymethyl-1-vinylimidazolium in presence of modified nanozeolite, and characterized by Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD) analysis, and transmission electron microscopy (TEM). The resulting heterogeneous catalyst displayed high catalytic performance under mild reaction condition in short reaction time. The catalyst was recycled eight times without any loss in reactivity or yield.

CsxH3-xPW12O40 nanoparticles dispersed in the porous network of Zr-pillared α-zirconium phosphate as efficient heterogeneous catalyst for synthesis of spirooxindoles

Layered α-zirconium phosphate (α-ZrP) was prepared by reflux method using ZrOCl2.8H2O and H3PO4 as precursor. The α-ZrP material was pillared with Zr-oxyhydroxy nanoclusters to prepare Zr-pillared α-zirconium phosphate (ZZP). An enhancement in interlayer spacing, surface area and porosity was noticed as a result of Zr-pillaring. The cesium exchanged phosphotungstic acid (CsxH3-xPW12O40) nanoparticles were dispersed in the porous matrix of ZZP material to prepare CsxH3-xPW12O40-ZZP nanocomposite systems. The nanocomposites were characterized using XRD, FTIR, UV–vis-DRS, TGA-DTA, XPS, N2 sorption, TPD, FESEM and HRTEM techniques. The expansion in layer structure of α-ZrP upon pillaring and its subsequent retention in the composite material was noticed from XRD. UV–vis and FTIR study indicated structural integrity of the CsxH3-xPW12O40 nanoclusters in the ZZP interlayer. The surface area of the composite materials was in the range of 80–130 m2 g−1. The composite materials contained significantly higher amount of medium and strong acidic sites compared to the ZP and ZZP materials. Microscopic study suggested the presence of hierarchical nanospheres with diameter between 150 and 200 nm. The presence of well dispersed CsxH3-xPW12O40 nanoparticles with size between 8 and 15 nm was confirmed from HRTEM study. The nanocomposite materials were used as efficient heterogeneous catalyst for synthesis of spirooxindoles by multicomponent one pot condensation of isatin, malononitrile, naphthol/1,3-diketones. Structurally diverse spirooxindole derivatives were synthesized in high yield and purity in short span of time using the CsxH3-xPW12O40-ZZP nanocomposites as catalyst under mild conditions.

Unprecedented NH2-MIL-101(Al)/n-Bu4NBr system as solvent-free heterogeneous catalyst for efficient synthesis of cyclic carbonates via CO2 cycloaddition.

Amine-functionalised framework NH2-MIL-101(Al) was synthesized using a solvothermal and microwave method and characterized by PXRD, FT-IR, TGA, SEM-EDX, and BET surface area analysis. The desolvated framework, in the presence of co-catalyst tetrabutylammonium bromide (TBAB), acted as an excellent heterogeneous catalyst for the solvent-free cycloaddition of carbon dioxide (CO2) with epoxides, affording five-membered cyclic carbonates. Using styrene oxide, the NH2-MIL-101(Al)/TBAB system showed more than 99% conversion, affording 96% yield and 99% selectivity with a turn over frequency of 23.5 h-1. This validated the synergistic effect of the quaternary ammonium salt during CO2 cycloaddition. The catalyst could be recycled at least five times without a noticeable loss in activity, while leaching test showed no leached Al3+ ions throughout the reaction. Thorough analysis of the reaction parameters showed that the optimum conditions for obtaining the maximum yield and highest selectivity were 120 °C and 18 bar of CO2 for 6 h. The outstanding conversion and selectivity were maintained for a range of aliphatic and aromatic epoxides, corroborating the duel benefit of the micro-mesoporous system with amine functionality, which offered easy access for reactant molecules with diverse sizes, and provided inspiration for future CO2 cycloaddition catalytic systems. We also propose a rationalized mechanism for the cycloaddition reaction mediated by NH2-MIL-101(Al) and TBAB based on literature precedent and experimental outcome.

Nanoporous Na+-montmorillonite perchloric acid as an efficient heterogeneous catalyst for synthesis of merocyanine dyes based on isoxazolone and barbituric acid

Nanoporous Na+-montmorillonite perchloric acid (MPA) as a novel heterogeneous solid acid catalyst was easily prepared. The physico-chemical properties of the catalyst were analyzed by a variety of techniques including X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), energy dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller (BET) and nitrogen adsorption-desorption measurements, pH analysis and Hammett acidity function. The prepared reagent showed excellent catalytic activity for the green one-pot, three component synthesis of 3-methyl-4-arylmethylene-isoxazol-5(4H)-one, pyrano [2,3-d] pyrimidinone and 5-arylidine barbituric acid derivatives in aqueous media. The remarkable features of the present protocol are availability and low cost of the starting materials, reusability of the catalyst, short reaction times and high yields of the products.

One-pot multicomponent synthesis in aqueous medium of 1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile and derivatives using a green and reusable nano-SiO2 catalyst from agricultural waste

Nanosilica from wheat straw—an agricultural waste—was utilized as a novel and efficient heterogeneous catalyst for synthesis of bioactive pyrano[2,3-c]pyrazole derivatives via one-pot four-component reaction of various aryl aldehydes, hydrazine hydrate, ethyl acetoacetate, and malononitrile in aqueous medium at 80 °C. The nano-SiO2 extracted from wheat straw was characterized by Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) analysis, particle size analysis, energy-dispersive X-ray (EDX) analysis, and scanning electron microscopy (SEM). All the synthesized pyrano[2,3-c]pyrazoles were characterized by FT-IR spectroscopy, electrospray ionization (ESI) mass spectroscopy (MS), 1H and 13C nuclear magnetic resonance (NMR), and elemental analysis. Additional features of this method include an efficient, rapid, and ecofriendly reaction process, easy workup, high yield, short reaction time, and recyclable green catalyst.

Cobalt ferrite encapsulated in a zwitterionic chitosan derived shell: An efficient nano‐magnetic catalyst for three‐component syntheses of pyrano[3,2‐c]quinolines and spiro‐oxindoles

A nano‐magnetic core‐shell composite fabricated of a unique zwitterionic chitosan‐derived coating and cobalt ferrite core was found to be a green and reusable heterogeneous catalyst for efficient synthesis of pyrano[3,2‐c]quinoline and spiro‐oxindole derivatives in high to excellent yields. Due to having negative charges at its outermost layer and a high magnetization, the catalyst is finely dispersed in ethanol and can be easily separated from reaction mixtures by using a simple external magnet. It is reasonably stable as can be reused several times without appreciable loss of catalytic activity.

Facile Suzuki-Miyaura cross coupling using ferrocene tethered N-heterocyclic carbene-Pd complex anchored on cellulose

A novel ferrocene tethered N-heterocyclic carbene-Pd complex anchored on cellulose has been prepared by multi-step synthesis. The complex proved to be robust and efficient heterogeneous catalyst for synthesis of biaryls in Suzuki-Miyaura cross coupling reaction.

Preparation, characterization, and use of poly(vinylpyrrolidonium) hydrogen phosphate ([PVP-H]H2PO4) as a new heterogeneous catalyst for efficient synthesis of 2-amino-tetrahydro-4H-pyrans

A novel Bronsted solid acid named poly(vinylpyrrolidonium) hydrogen phosphate ([PVP-H]H2PO4) has been prepared by using H3PO4 and poly(vinylpyrrolidone) as green and commercially available reagents. The prepared reagent was characterized using a series of techniques including Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, energy-dispersive X-ray analysis (EDAX), pH analysis, and Hammett acidity function. The mentioned solid acid with wide acidic functional group sites can be utilized as a highly efficient, heterogeneous, and reusable catalyst for preparation of 2-amino-3-cyano-5-oxo-5,6,7,8-tetrahydro-4H-benzopyrans using aldehydes, dimedone, and malononitrile. Also, this catalyst can be reused for several times without loss of catalytic activity.

Vitamin B1 supported on alumina as an efficient heterogeneous catalyst for synthesis of tetrahydro-2,6-dioxopyrimidin-4-yl)-2,3-dihydrophthalazine-1,4-dione derivatives

The efficient synthesis of tetrahydro-2,6-dioxopyrimidin-4-yl)-2,3-dihydrophthalazine-1,4-dione derivatives via four-component reaction of hydrazine hydrate, phthalic anhydride, aromatic aldehydes and barbituric acid using vitamin B1 supported on alumina (VB1-Al2O3) as a heterogeneous catalyst under thermal solvent-free conditions in excellent yields is described.

ChemInform Abstract: Immobilized Palladium Nanoparticles on Silica—Starch Substrate (PNP—SSS): As a Stable and Efficient Heterogeneous Catalyst for Synthesis of p‐Teraryls Using Suzuki Reaction.

AbstractA variety of para‐, meta‐ and ortho‐teraryls is prepared in high yields under aqueous conditions from the corresponding benzene diiodides, dichlorides and dibromides.

ChemInform Abstract: Mesoporous AlPO4: A Highly Efficient Heterogeneous Catalyst for Synthesis of 5‐Substituted 1H‐Tetrazoles from Nitriles and Sodium Azide via [3 + 2] Cycloaddition.

AbstractMesoporous aluminum phosphate is described as possible candidate to substitute metal salts or other heterogeneous catalysts even in industrial applications.