scholarly journals Applications of Cu(0) encapsulated nanocatalysts as superior catalytic systems in Cu-catalyzed organic transformations

RSC Advances ◽  
2020 ◽  
Vol 10 (42) ◽  
pp. 24893-24940 ◽  
Author(s):  
Majid M. Heravi ◽  
Bahareh Heidari ◽  
Vahideh Zadsirjan ◽  
Leila Mohammadi
Keyword(s):  
Catalytic Activity ◽  
Porous Materials ◽  
Metal Ion ◽  
Organic Transformations ◽  
Catalytic Systems

In this review, the catalytic activity of encapsulated Cu-NPs in different important organic transformations is compared with those of a variety of organic, inorganic and hybrid porous materials bearing a traded metal ion.

Catalytic Activity of Binary and Triple Systems Based on Redox Inactive Metal Compound, LiSt and Additives of Monodentate Ligands-Modifiers: DMF, HMPA and PhOH, in Selective Ethylbenzene Oxidation with Dioxygen

2016 ◽  
Vol 10 (3) ◽  
pp. 259-270
Author(s):  
Ludmila Matienko ◽  
◽  
Larisa Mosolova ◽  
Vladimir Binyukov ◽  
Gennady Zaikov ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Triple System ◽  
Metal Compound ◽  
Ethylbenzene Oxidation ◽  
Catalytic Systems ◽  
Triple Systems ◽  
Lithium Compound ◽  
Mechanism Of Catalysis ◽  
Monodentate Ligands

Mechanism of catalysis with binary and triple catalytic systems based on redox inactive metal (lithium) compound {LiSt+L2} and {LiSt+L2+PhOH} (L2=DMF or HMPA), in the selective ethylbenzene oxidation by dioxygen into -phenylethyl hydroperoxide is researched. The results are compared with catalysis by nickel-lithium triple system {NiII(acac)2+LiSt+PhOH} in selective ethylbenzene oxidation to PEH. The role of H-bonding in mechanism of catalysis is discussed. The possibility of the stable supramolecular nanostructures formation on the basis of triple systems, {LiSt+L2+PhOH}, due to intermolecular H-bonds, is researched with the AFM method.

Nickel (II) and oxovanadium (IV) complexes supported on MCM-41 mesoporous and their application in catalytic selective sulfide and thiol oxidation

2020 ◽  
Vol 23 ◽  
Author(s):  
Mohsen Nikoorazm ◽  
Maryam Khanmoradi ◽  
Masoumeh Sayadian
Keyword(s):  
Catalytic Activity ◽  
Room Temperature ◽  
Sol Gel ◽  
Reaction Times ◽  
Significant Loss ◽  
Spectral Studies ◽  
High Catalytic Activity ◽  
Catalytic Systems ◽  
Solvent Free Conditions ◽  
Mcm 41

Introduction:: MCM-41 was synthesized using the sol-gel method. Then two new transition metal complexes of Nickel (II) and Vanadium (IV), were synthesized by immobilization of adenine (6-aminopurine) into MCM-41 mesoporous. The compounds have been characterized by XRD, TGA, SEM, AAS and FT-IR spectral studies. Using these catalysts provided an efficient and enantioselective procedure for oxidation of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides using hydrogen peroxide at room temperature. Materials and Methods:: To a solution of sulfide or thiol (1 mmol) and H2O2 (5 mmol), a determined amount of the catalyst was added. The reaction mixture was stirred at room temperature for the specific time under solvent free conditions. The progress of the reaction was monitored by TLC using n-hexane: acetone (8:2). Afterwards, the catalyst was removed from the reaction mixture by centrifugation and, then, washed with dichloromethane in order to give the pure products. Results:: All the products were obtained in excellent yields and short reaction times indicating the high activity of the synthesized catalysts. Besides, the catalysts can be recovered and reused for several runs without significant loss in their catalytic activity. Conclusion:: These catalytic systems furnish the products very quickly with excellent yields and VO-6AP-MCM-41 shows high catalytic activity compared to Ni-6AP-MCM-41.

Hydrogen peroxide decomposition on a two-component CuO-Cr2O3 catalyst

1988 ◽  
Vol 53 (8) ◽  
pp. 1636-1646 ◽  
Author(s):  
Viliam Múčka ◽  
Kamil Lang
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Extreme Values ◽  
Catalytic Properties ◽  
Active Components ◽  
Catalytic Systems ◽  
Heterogeneous Catalytic ◽  
Peroxide Decomposition ◽  
Two Component ◽  
Catalytically Active

Some physical and catalytic properties of the two-component copper(II)oxide-chromium(III)oxide catalyst with different content of both components were studied using the decomposition of the aqueous solution of hydrogen peroxide as a testing reaction. It has been found that along to both basic components, the system under study contains also the spinel structure CuCr2O4, chromate washable by water and hexavalent ions of chromium unwashable by water. The soluble chromate is catalytically active. During the first period of the reaction the equilibrium is being established in both homogeneous and heterogeneous catalytic systems. The catalytic activity as well as the specific surface area of the washed solid is a non-monotonous function of its composition. It seems highly probable that the extreme values of both these quantities are not connected with the detected admixtures in the catalytic system. The system under study is very insensitive with regard to the applied doses of gamma radiation. Its catalytic properties are changed rather significantly after the thermal treatment and particularly after the partial reduction to low degree by hydrogen. The observed changes of the catalytic activity of the system under study are very probably in connection with the changes of the valence state of the catalytically active components of the catalyst.

scholarly journals Co3O4/TiO2 hetero-structure for methyl orange dye degradation

2018 ◽  
Vol 79 (5) ◽  
pp. 947-957 ◽  
Author(s):  
Mahabubur Chowdhury ◽  
Sarah Kapinga ◽  
Franscious Cummings ◽  
Veruscha Fester
Keyword(s):  
Catalytic Activity ◽  
Methyl Orange ◽  
Environmental Remediation ◽  
Metal Ion ◽  
Dye Degradation ◽  
Lattice Structure ◽  
Host Lattice ◽  
Commercial Application ◽  
Potential Candidate ◽  
Methyl Orange Degradation

Abstract Advanced oxidation processes based on sulphate radical generated by peroxymonosulphate (PMS) activation is a promising area for environmental remediation. One of the biggest drawbacks of heterogeneous PMS activation is catalyst instability and metal ion leaching. In this study, a simple organic binder mediated route was explored to substitute Ti4+ ions into the Co3O4 host lattice structure to create a Co-O-Ti bond to minimise cobalt leaching during methyl orange degradation. The catalyst was characterised by X-ray diffraction, and scanning and transmission electron microscopy. The as-prepared catalysts with Co3O4:TiO2 ratio of 70:30 exhibited minimal leaching (0.9 mg/L) compared to other ratios studied. However, the pristine Co3O4 exhibited highest catalytic activity (rate constant = 0.41 min−1) and leaching (26.7 mg/L) compared to composite material (70:30 Co3O4:TiO2). Interestingly, the morphology of the composite and leaching of Co2+ ions were found to be temperature dependent, as an optimum temperature ensured strong Co-O-Ti bond for prevention of Co2+ leaching. The classical quenching test was utilised to determine the presence and role of radical species on methyl orange degradation. The fabricated catalyst also exhibited good catalytic activity in degrading mixed dyes and good recyclability, making it a potential candidate for commercial application.

scholarly journals Pd(0) encapsulated nanocatalysts as superior catalytic systems for Pd-catalyzed organic transformations

RSC Advances ◽  
2016 ◽  
Vol 6 (91) ◽  
pp. 88588-88624 ◽  
Author(s):  
S. Sadjadi ◽  
M. M. Heravi
Keyword(s):  
Chemical Reactions ◽  
Organic Transformations ◽  
Catalytic Systems

In the last decade, Pd(0) nanoparticles have attracted increasing attention due to their outstanding utility as nanocatalysts in a wide variety of key chemical reactions.

scholarly journals Volcano-Type Correlation between Particle Size and Catalytic Activity on Hydrodechlorination catalyzed by AuPd Nanoalloy

2020 ◽  
Author(s):  
Yuta Uetake ◽  
Sachi Mouri ◽  
Setsiri Haesuwannakij ◽  
Kazu Okumura ◽  
Hidehiro Sakurai
Keyword(s):  
Catalytic Activity ◽  
Metal Ion ◽  
Mixing Time ◽  
Metal Nanoparticle ◽  
Edge Structure ◽  
X Ray ◽  
Rate Determining Step ◽  
Transmission Electron ◽  
Random Alloy ◽  
X Ray Absorption

<div>Although changing the size of metal nanoparticle (NP) is a reasonable way to tune and/or enhance their catalytic activity, size-selective preparation of NP possessing random-alloy morphology has been challenging because of the differences in the ionization potential of each metal ion. This study demonstrates a time-controlled aggregation–stabilization method for a size-selective preparation of random alloy NPs composed of Au and Pd, which are stabilized by poly(<i>N</i>-vinyl-2-pyrrolidone) (PVP). By adjusting the mixing time in the presence of a small amount of PVP, the aggregation was induced to produce AuPd:PVP with sizes ranging between 1.2 and 8.2 nm at approximately 1 nm intervals. Transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and extended x-ray absorption fine structure (EXAFS) analyses clearly indicated the formation of various sizes of AuPd nanoalloys with almost the same morphology, and size-dependent catalytic activity was observed when hydrodechlorination of 4-choroanisole was performed using 2-propanol as a reducing agent. AuPd:PVP with a size of 3.1 nm exhibited the highest catalytic activity. A comparison of the absorption edges on x-ray absorption near edge structure (XANES) spectra suggested that the electronic state of the Au and Pd species correlated with their catalytic activity, presumably affecting the rate-determining step.</div><div> </div>

scholarly journals Metal Complexes of Schiff Bases of 3-Hydroxyquinoxaline-2-carboxaldehyde Encapsulated in Zeolite Y Cages: Potential Catalyst for Removing Phenol from Effluent Media

2021 ◽  
Vol 33 (11) ◽  
pp. 2746-2754
Author(s):  
N.R. Suja ◽  
T.K. Bindu Sharmila ◽  
S.R. Amrutha
Keyword(s):  
Catalytic Activity ◽  
Transition Metal ◽  
Metal Complexes ◽  
Schiff Bases ◽  
Transition Metal Complexes ◽  
Zeolite Y ◽  
Point Of View ◽  
Organic Transformations ◽  
Efficient Catalyst ◽  
Industrial Pollutants

Transition metal complexes are known to be efficient catalyst for many organic transformations. Encapsulation of metal complexes in zeolite cage brings many significant modifications in the structure of the metal complexes, which are very interesting from the catalytic point of view. This study aims in a comparative evaluation of the influence of structure of neat and encapsulated complexes in their catalytic activity. Phenol is one of the major industrial pollutants. Heterogenizing transition metal Schiff bases by encapsulation inside the zeolite would help to minimize the reuse problem of transition metal complexes. This article deals with the synthesis, characterization and catalytic activity studies of Co(II), Ni(II) and Cu(II) complexes of 3-hydroxyquinoxaline-2-carboxaldehyde with ethylenediamine (L1) and an o-phenylene diamine (L2).

Effects of Vanadate on the Molybdoproteins Xanthine Oxidase and Nitrate Reductase: Kinetic Evidence for Multiple Site Interaction

1980 ◽  
Vol 35 (9-10) ◽  
pp. 702-707 ◽  
Author(s):  
Candadai S. Ramadoss
Keyword(s):  
Catalytic Activity ◽  
Nitrate Reductase ◽  
Xanthine Oxidase ◽  
Oxidase Activity ◽  
Metal Ion ◽  
Nadh Oxidase ◽  
Multiple Site ◽  
Vanadate Inhibition ◽  
Nadh Oxidase Activity

Abstract The inhibition of the activity of xanthine oxidase by vanadate was strikingly similar to vanadate inhibition of another molybdoprotein nitrate reductase. Although the main catalytic activity of both enzymes was inhibited, the partial NADH oxidase activity associated with these enzymes was stimulated several fold. It appears that the metal ion binds at multiple site in both enzymes. In the absence of any enzymes a combination of vanadium (V) and molybdenum (V) in air was found to oxide NADH rapidly.

scholarly journals THE METAL COMPLEXES OF NOVEL SCHIFF BASE CONTAINING ISATIN: CHARACTERIZATION, ANTIMICROBIAL, ANTIOXIDANT AND CATALYTIC ACTIVITY STUDY

2019 ◽  
pp. 206-210
Author(s):  
VAIRALAKSHMI M ◽  
PRINCESS R ◽  
JOHNSON RAJA S
Keyword(s):  
Catalytic Activity ◽  
Metal Complexes ◽  
1H Nmr ◽  
Metal Ion ◽  
Analytical Data ◽  
Free Ligand ◽  
Molar Conductance ◽  
Diffusion Method ◽  
Spectral Studies ◽  
Standard Drug

Objectives: The aim of our work was to synthesize novel mixed ligand-metal complexes and evaluation of antimicrobial, antioxidant assay, and analysis of catalytic oxidation of cyclohexane. Methods: The complexes were characterized by means of various physicochemical techniques such as elemental analysis, molar conductance, magnetic susceptibility, infrared (IR), electronic absorption, 1H NMR (proton magnetic resonance), and mass spectral studies. The antimicrobial screening study was done by disc diffusion method. The catalytic activity of the complexes was observed in the oxidation of cyclohexane using eco-friendly hydrogen peroxide as oxidant. Results: On comparing the 1H NMR and IR spectral data of free ligand and its complexes, it was found to be azomethine (CH=N) proton which is formed in the free ligand. During complexation, the azomethine proton is coordinated to the metal ion and the phenolic oxygen is coordinated to the metal ion by deprotonation. The analytical data and mass spectra of the ligand and the complexes confirm the stoichiometry of metal complexes as being of the (MLY)Cl type and the metal to ligand ratio is 1:1. The antimicrobial, antioxidant, and catalytic potential were evaluated and the result shows the better activity of the complexes than the ligand. Conclusion: It was found to be copper(II) and zinc(II) complexes which are effective against all the bacteria when compared to standard drug streptomycin. Copper(II) complex was found to be effective antibacterial agent against Aspergillus niger and Aspergillus flavus in comparison to the standard drug Nystatin. The zinc complex exhibited good catalytic activity.

scholarly journals Preparation of hydroxyapatite-based porous materials for absorption of lead ions

2019 ◽  
Vol 80 (7) ◽  
pp. 1266-1275
Author(s):  
Zejun Wang ◽  
Kangqi Sun ◽  
Yufeng He ◽  
Pengfei Song ◽  
Dawei Zhang ◽  
...  
Keyword(s):  
Porous Materials ◽  
Metal Ion ◽  
Ph Value ◽  
Soybean Protein ◽  
Protein Isolate ◽  
Soybean Protein Isolate ◽  
Bet Analysis ◽  
Initial Ph ◽  
Infrared Spectrometer ◽  
Composition Structure

Abstract In this paper, soybean protein isolate (SPI) was used as template, hydroxyapatite was crystallized on protein chains of SPI by in-situ synthesis, then the obtained inorganic HA/biopolymer SPI composite (HA@SPI) was calcined at suitable temperature, which afforded a novel hydroxyapatite-based porous materials (HApM). The results indicated that the product showed a porous morphology structure and excellent absorption performance for Pb2+. HApM maximum removal of lead was attained (96.25%) at an initial pH value of 7.4, temperature of 25 °C and contact time of 30 min with an initial metal concentration of 60 mg/L. In order to identify composition, structure and functional groups involved in the uptake of Pb2+, Fourier transform infrared spectrometer (FTIR), thermogravimetric analysis (TG), X-ray diffraction (XRD) scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Brunauer–Emmett–Teller (BET) analysis were carried out. Therefore, the hydroxyapatite-based porous materials (HApM) is a promising candidate for the treatment of liquid wastes containing toxic Pb2+ metal ion, heavy metal ion antidotes and other related fields.

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