Catalytic performance of a Keplerate-type, giant-ball nanoporous isopolyoxomolybdate as a highly efficient recyclable catalyst for the synthesis of biscoumarins

2016 ◽  
Vol 71 (3) ◽  
pp. 219-225 ◽  
Author(s):  
Abolghasem Davoodnia ◽  
Ahmad Nakhaei ◽  
Niloofar Tavakoli-Hoseini
Keyword(s):  
Catalytic Activity ◽  
Catalytic Performance ◽  
High Catalytic Activity ◽  
Synthetic Approach ◽  
Organic Transformations ◽  
Aliphatic Aldehydes ◽  
Short Reaction Time ◽  
Type Giant ◽  
High Yields ◽  
Work Up

AbstractIn continuation of our previous works on the application of (NH4)42[MoVI72MoV60O372(CH3COO)30(H2O)72], a Keplerate-type giant-ball nanoporous isopolyoxomolybdate, as a catalyst for a series of organic transformations, in this paper, we discovered that this new attractive catalyst has high catalytic activity in the synthesis of biscoumarins prepared by the reaction of 4-hydroxycoumarin and aromatic or aliphatic aldehydes in refluxing ethanol. The catalyst was prepared according to a previously published literature procedure using inexpensive and readily available starting materials. Furthermore, the catalyst could be recovered conveniently and reused efficiently such that a considerable catalytic activity still could be achieved after fifth run. Other beneficial features of this new synthetic approach include short reaction time, high yields, clean reaction profiles, and a simple work-up procedure.

scholarly journals Bio-assisted synthesized Ag(0) nanoparticles stabilized on hybrid of sepiolite and chitin: efficient catalytic system for xanthene synthesis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Fatemeh Ghoreyshi Kahangi ◽  
Morteza Mehrdad ◽  
Majid M. Heravi ◽  
Samahe Sadjadi
Keyword(s):  
Silver Nanoparticles ◽  
Catalytic Activity ◽  
Specific Surface ◽  
Catalytic System ◽  
Synergistic Effects ◽  
Aqueous Media ◽  
Catalytic Performance ◽  
High Catalytic Activity ◽  
Mean Diameter ◽  
High Yields

Abstract In this work, with the use of two natural compounds, chitin and sepiolite clay, a novel covalent hybrid is fabricated and applied as a support for the stabilization of silver nanoparticles with the aid of Kombucha extract as a natural reducing agent. The resultant catalytic system, Ag@Sep-N–CH, was characterized via XRD, TEM, FTIR, ICP, SEM, TGA, UV–Vis and BET. It was found that fine Ag(0) nanoparticles with mean diameter of 6.1 ± 1.8 nm were formed on the support and the specific surface area of the catalyst was 130 m2 g−1. The study of the catalytic performance of Ag@Sep-N–CH for catalyzing synthesis of xanthenes in aqueous media under mild reaction condition confirmed that Ag@Sep-N–CH exhibited high catalytic activity and could promote the reaction of various substrates to furnish the corresponding products in high yields. Moreover, the contribution of both chitin and sepiolite to the catalysis has been affirmed. It was found that hybridization of these two components led to synergistic effects and consequently improved the observed catalytic activity. Notably, the catalyst was recyclable up to several reaction runs.

scholarly journals Zn(L-proline)2: An efficient and reusable organocatalyst for the synthesis of polyfunctionally substituted pyrans and 2-amino-4-aryl-8-oxo-4,8-dihydropyrano[3,2-b]pyran derivatives

2019 ◽  
Vol 10 (2) ◽  
pp. 166-170 ◽  
Author(s):  
Fatma Ahmed Abo Elsoud ◽  
Mohamed Abd-Elmonem ◽  
Mohamed Abo Elsebaa ◽  
Kamal Usef Sadek
Keyword(s):  
Kojic Acid ◽  
Aromatic Aldehydes ◽  
Efficient Synthesis ◽  
Atom Economy ◽  
Short Reaction Time ◽  
Biologically Relevant ◽  
Three Component Reaction ◽  
High Yields ◽  
Organometallic Catalyst ◽  
Work Up

Efficient synthesis of non-annulated 2-amino-4H-pyrans and 2-amino-8-oxo-4,8-dihydropyrano[3,2-b]pyran derivatives, which are biologically relevant heterocycles is achieved, utilizing a domino three-component reaction of ethyl acetoacetate or kojic acid with aromatic aldehydes and malononitrile catalyzed by Zn(L-proline)2 as reusable organometallic catalyst. The process exhibits high atom economy, short reaction time, simple work up, high yields and environmentally friendly nature. Excellent yields of the targeted molecules have been obtained.

Facile preparation of a hierarchically porous metal–organic nanocomposite with excellent catalytic performance

RSC Advances ◽  
2016 ◽  
Vol 6 (99) ◽  
pp. 97399-97403 ◽  
Author(s):  
Rui Kuang ◽  
Luyi Zheng ◽  
Ethan Cottrill ◽  
Ning Pan ◽  
Yanhui Chi ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Aging Process ◽  
Porous Metal ◽  
Catalytic Performance ◽  
High Catalytic Activity ◽  
Hierarchically Porous ◽  
Hierarchical Porous ◽  
Metal Organic ◽  
Facile Preparation ◽  
Excellent Catalytic Performance

A hierarchical porous MOF nanocrystal, hpCuL (L = 2,4,6-tris(3,5-dicarboxylatephenylamino)-1,3,5-triazine) was prepared via a facile gel-aging process. This nanocomposite exhibits high catalytic activity and stability for the reduction of 4-nitrophenol.

MOF-derived Co1.11Te2 with half-metallic character for efficient photochemical conversion of CO2 under visible-light irradiation

2019 ◽  
Vol 55 (48) ◽  
pp. 6862-6865 ◽  
Author(s):  
Yong Xu ◽  
Jiang Mo ◽  
Guanqun Xie ◽  
Dawei Ding ◽  
Shujiang Ding ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Catalytic Activity ◽  
Energy Barrier ◽  
Catalytic Performance ◽  
Carbon Layer ◽  
Low Energy ◽  
High Catalytic Activity ◽  
Key Factors ◽  
Strong Electron ◽  
Half Metallic

Co1.11Te2 enwrapped in a carbon layer displayed high catalytic performance for photocatalytic CO2 reduction. The strong electron transfer ability and the low energy barrier are the key factors that promote its high catalytic activity.

ZnO nanoparticles in the synthesis of AB ring core of camptothecin

2010 ◽  
Vol 64 (6) ◽  
Author(s):  
Selvaraj Roopan ◽  
Fazlur Nawaz Khan
Keyword(s):  
Zinc Oxide ◽  
Reaction Time ◽  
Zinc Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Short Reaction Time ◽  
High Yields ◽  
Work Up ◽  
First Time ◽  
Ab Ring ◽  
Ring Core

AbstractFor the first time, synthesis of AB ring core of camptothecin synthons such as (2-chloroquinolin-3-yl)methanols (Va-Vg) using zinc oxide nanoparticles is reported. The desired attractive products were obtained in high yields, short reaction time, using a simple work-up procedure with the purification of products by non-chromatographic methods.

Ruthenium- and Rhodium-Catalyzed Ring-Opening Coupling Reactions of Cyclopropenones with Alkenes or Alkynes

Synlett ◽  
2018 ◽  
Vol 29 (06) ◽  
pp. 717-722 ◽  
Author(s):  
Teruyuki Kondo ◽  
Ryosuke Taniguchi ◽  
Yu Kimura
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Methyl Acrylate ◽  
Ring Opening ◽  
Argon Atmosphere ◽  
High Catalytic Activity ◽  
Rhodium Complexes ◽  
Coupling Reactions ◽  
Internal Alkynes ◽  
High Yields

Ru3(CO)12-catalyzed divergent ring-opening coupling reactions of a cyclopropenone with methyl acrylate (an electron-deficient alkene) are developed. Under an argon atmosphere, a decarbonylative linear codimer is obtained, while cyclopentenones are obtained under carbon monoxide (20 atm) without decarbonylation. While ruthenium complexes show no catalytic activity for the ring-opening cocyclization of cyclopropenones with ethylene (20 atm) or bicyclo[2.2.1]hept-2-ene (2-norbornene), rhodium complexes, especially [RhCl(η4-1,5-cod)]2, show high catalytic activity for the desired cocyclization reactions to give the corresponding cyclopentenones in high yields and selectivities. In addition, [RhCl(η4-1,5-cod)]2 realizes the catalytic ring-opening co­cyclization of cyclopropenones with internal alkynes to give the corresponding cyclopentadienones. In all these reactions, ruthena- or rhodacyclobutenones are considered to be key intermediates, generated by strain-driven oxidative addition of a cyclopropenone C–C bond to an ­active ruthenium or rhodium species.

Catalytic activity of dithioic acid copper complexes in the alkyne–azide cycloaddition

2013 ◽  
Vol 91 (4) ◽  
pp. 292-299 ◽  
Author(s):  
Bayardo E. Velasco ◽  
Gustavo López-Téllez ◽  
Nelly González-Rivas ◽  
Iván García-Orozco ◽  
Erick Cuevas-Yañez
Keyword(s):  
Catalytic Activity ◽  
Copper Complex ◽  
Copper Complexes ◽  
Functional Group ◽  
High Efficiency ◽  
High Catalytic Activity ◽  
Different Temperatures ◽  
High Yields

Diverse dithioic acid copper complexes exhibit a high catalytic activity in the copper-catalyzed alkyne–azide cycloaddition using several solvents under different temperatures, showing a high efficiency with only 0.005 mmol catalyst/mmol alkyne or less. A dithioic acid copper complex derived from acetophenone was selected and used as the catalyst in the preparation of a library of 1,4-disubstituted-1,2,3-triazoles. This process occurred in high yields and good functional group tolerance.

scholarly journals Biodiesel Production over Niobium-Containing Catalysts: A Review

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5506
Author(s):  
Daniel Carreira Batalha ◽  
Márcio José da Silva
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Raw Materials ◽  
Catalytic Performance ◽  
High Specific Surface Area ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Main Reaction ◽  
High Catalytic Activity

Nowadays, the synthesis of biofuels from renewable raw materials is very popular. Among the various challenges involved in improving these processes, environmentally benign catalysts compatible with an inexpensive feedstock have become more important. Herein, we report the recent advances achieved in the development of Niobium-containing heterogeneous catalysts as well as their use in routes to produce biodiesel. The efficiency of different Niobium catalysts in esterification and transesterification reactions of lipids and oleaginous raw materials was evaluated, considering the effect of main reaction parameters such as temperature, time, catalyst load, and oil:alcohol molar ratio on the biodiesel yield. The catalytic performance of Niobium compounds was discussed considering the characterization data obtained by different techniques, including NH3-TPD, BET, and Pyr-FT-IR analysis. The high catalytic activity is attributed to its inherent properties, such as the active sites distribution over a high specific surface area, strength of acidity, nature, amount of acidic sites, and inherent mesoporosity. On top of this, recycling experiments have proven that most Niobium catalysts are stable and can be repeatedly used with consistent catalytic activity.

scholarly journals Properties and catalytic performance of sulphate-vanadia impregnated fumed silica as oxidative catalyst

2015 ◽  
Vol 11 (2) ◽  
Author(s):  
Nor Masdiana Zulkeple ◽  
Norhasyimah Mohd Kamal ◽  
Jamilah Mohd Ekhsan ◽  
Salasiah Che Me ◽  
Swee Ean Lim ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Charge Transfer ◽  
Surface Area ◽  
Sulphuric Acid ◽  
Fumed Silica ◽  
Catalytic Performance ◽  
Support Surface ◽  
High Catalytic Activity ◽  
Impregnation Method

A series of sulphate-vanadia impregnated fumed silica oxidative catalysts were synthesized via impregnation method. The samples were prepared by impregnation of 1 wt% of vanadium and 0.2 M of sulphuric acid onto fumed silica as support. Surface area of the silica supported samples were similar of 118 m2/g. UV-Vis DRS results showed existence of o supported V species and the charge transfer bands associated with O2- to V5+ in tetrahedral environments. Catalytic performance were evaluated via epoxidation of 1-octene to 1,2-epoxyoctane using hydrogen peroxide as an oxidant. It had been demonstrated that sulphate-vanadia impregnated fumed silica had high catalytic activity of 626 ± 0.2 mmol epoxide was produced after 24 h reaction. This may indicate that more oxidative sites were generated after the impregnation of V and sulphate onto the SiO2 matrixes.

scholarly journals Fe3O4@chitosan-tannic acid bionanocomposite as a novel nanocatalyst for the synthesis of pyranopyrazoles

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maryam Kamalzare ◽  
Mohammad Reza Ahghari ◽  
Mohammad Bayat ◽  
Ali Maleki
Keyword(s):  
Reaction Time ◽  
Tannic Acid ◽  
High Performance ◽  
Catalytic Performance ◽  
Natural Material ◽  
Magnetic Nanocatalyst ◽  
Reaction Conditions ◽  
One Pot ◽  
Short Reaction Time ◽  
High Yields

AbstractRecently magnetic nanocatalyst has attracted considerable attention because of its unique properties, including high performance, easy separation from the reaction mixture, and recyclability. In this study, a novel magnetic bionanocomposite was synthesized with chitosan and tannic acid as a natural material. The synthesized bionanocatalyst was characterized by essential analysis. Fe3O4@chitosan-tannic acid as a heterogeneous nanocatalyst was successfully applied to synthesize pyranopyrazole and its derivatives by a one-pot four-component reaction of malononitrile, ethyl acetoacetate, hydrazine hydrate, and various aromatic aldehyde. At the end of the reaction, the nanocatalyst was separated from the reaction mixture and was reused several times with no significant decrease in its catalytic performance. Simple purification of products, the ability for recovering and reusing the nanocatalyst, eco-friendliness, high yields of pure products, mild reaction conditions, short reaction time, non-toxicity, economically affordable are some of the advantages of using the fabricated nanocatalyst in the synthesis of pyranopyrazole.

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