Synthesis of smart bimetallic nano-Cu/Ag@SiO2for clean oxidation of alcohols

2017 ◽  
Vol 41 (22) ◽  
pp. 13377-13381 ◽  
Author(s):  
Arijit Saha ◽  
Soumen Payra ◽  
Subhash Banerjee
Keyword(s):  
Silver Nanoparticles ◽  
Catalytic Performance ◽  
Benzyl Alcohols ◽  
Nano Catalyst ◽  
Oxidation Of Alcohols

Silica (SiO2) supported bimetallic copper/silver nanoparticles (Cu/Ag@SiO2NPs) were synthesized for clean oxidation of benzoins/benzyl alcohols. All the reactions were fast, clean and high yielding (95–99%) and the Cu/Ag@SiO2nano-catalyst was reused eight times without loss of its catalytic performance.

scholarly journals Catalytic Degradability of p-Nitrophenol Using Ecofriendly Silver Nanoparticles

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1661
Author(s):  
Ganesh Shimoga ◽  
Ramasubba Reddy Palem ◽  
Soo-Hong Lee ◽  
Sang-Youn Kim
Keyword(s):  
Silver Nanoparticles ◽  
Waste Water Treatment ◽  
Aquatic Organisms ◽  
Catalytic Performance ◽  
Water Remediation ◽  
Short Report ◽  
Potential Threat ◽  
First Order Kinetics ◽  
Green Route ◽  
Nano Catalyst

In an effort to produce non-toxic and economically viable “green” protocols for waste water treatment, researchers are actively involved to develop versatile and effective silver nanoparticles (SNPs) as nano-catalyst from bio-based techniques. Since, p-nitrophenol (PNP) is one of the anthropogenic contaminants, considerable attention has been focused in catalytic degradability of PNP in wastewater treatment by curtailing serious effect on aquatic fauna. Ingestion of contaminants by aquatic organisms will not only affect the aquatic species but is also a potential threat to human health, especially if the toxic contaminants are involved in food chain. In this short report, we provided a comprehensive insight on few remarkable nanocatalysts especially based on SNPs and its biopolymer composites synthesized via ecofriendly “green” route. The beneficiality and catalytic performance of these silver nanocatalysts are concisely documented on standard model degradation reduction of PNP to p-aminophenol (PAP) in the presence of aqueous sodium borohydride. The catalytic degradation of PNP to PAP using SNPs follows pseudo first order kinetics involving six-electrons with lower activation energy. Furthermore, we provided a list of highly effective, recoverable, and economically viable SNPs, which demonstrated its potential as nanocatalysts by focusing its technical impact in the area of water remediation.

Oxidation of secondary alcohols and ethers by dimethyldioxirane

1999 ◽  
Vol 77 (3) ◽  
pp. 308-312 ◽  
Author(s):  
Alfons L Baumstark ◽  
Franci Kovac ◽  
Pedro C Vasquez
Keyword(s):  
Oxygen Atom ◽  
Methyl Ether ◽  
Radical Pair ◽  
Parent Compound ◽  
Activation Parameters ◽  
Silyl Ether ◽  
Secondary Alcohols ◽  
Benzyl Alcohols ◽  
Oxidation Of Alcohols ◽  
Direct Abstraction

The oxidation of several series of secondary alcohols 2-9, ethers 10-17, and related derivatives 18 and19, by dimethyldioxirane, 1, in acetone at 25°C produced the corresponding ketones in good to excellent yields for all but two cases. (The exceptions: oxidation of 1-methoxy-2-methyl-1-phenylpropane (48%) and 1-methoxy-2,2-dimethyl-1-phenylpropane (24%).) The oxidation of the secondary alcohols was found to yield k2 values that were roughly 10-fold greater than those of the corresponding methyl ethers. The rate constant for oxidation of a silyl ether was slightly lower than that for the corresponding methyl ether while that for the ester derivative was roughly half the value. For oxidation of alcohols and methyl ethers, the k2 values became smaller as the R " series (Me, Et, nPr, iPr, and tBu) increased in steric bulk (ρ* = 1.7; r = 0.998 and ρ* = 3.2; r = 0.95, respectively). The Hammett study for the oxidation of the methyl ethers of α-methyl-p-benzyl alcohols (10, 20-25) yielded a ρ value of -0.74. The activation parameters for oxidation of the parent compound of the ether series (1-methoxy-1-phenylethane) were ΔH‡ = 14.8 ± 0.5 kcal/mol, ΔS‡ = -21.9 eu, ΔG‡ = 21.3 kcal/mol, k2 (25°C) = 1.6 × 10-3 M-1 s-1. The mechanistic aspects of the oxidation are discussed in relation to two mechanistic extremes: (a) direct insertion of the oxygen atom into the C—H bond and (b) direct abstraction of the H by dimethyldioxirane to yield a caged-radical pair, with subsequent coupling to hemi-ketal intermediates that fragment to yield acetone, alcohol or water, and ketone as the final products.Key words: dimethyldioxirane, oxidation.

scholarly journals A Study of Catalytic Oxidation of a Library of C2 to C4 Alcohols in the Presence of Nanogold

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 442
Author(s):  
Maciej Kapkowski ◽  
Anna Niemczyk-Wojdyla ◽  
Piotr Bartczak ◽  
Monika Pyrkosz Bulska ◽  
Kamila Gajcy ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Green Chemistry ◽  
Alcohol Oxidation ◽  
Catalytic Performance ◽  
Toxic Chemicals ◽  
Wide Scope ◽  
Catalytic Potential ◽  
Green Oxidation ◽  
Oxidation Of Alcohols ◽  
Different Levels

The classical stoichiometric oxidation of alcohols is an important tool in contemporary organic chemistry. However, it still requires huge modifications in order to comply with the principles of green chemistry. The use of toxic chemicals, hazardous organic solvents, and the large amounts of toxic wastes that result from the reactions are a few examples of the problems that must be solved. Nanogold alone or conjugated with palladium were supported on different carriers (SiO2, C) and investigated in order to evaluate their catalytic potential for environmentally friendly alcohol oxidation under solvent-free and base-free conditions in the presence H2O2 as a clean oxidant. We tested different levels of Au loading (0.1–1.2% wt.) and different active catalytic site forms (monometallic Au or bimetallic Au–Pd sites). This provided new insights on how the structure of the Au-dispersions affected their catalytic performance. Importantly, the examination of the catalytic performance of the resulting catalysts was oriented toward a broad scope of alcohols, including those that are the most resistant to oxidation—the primary aliphatic alcohols. Surprisingly, the studies proved that Au/SiO2 at a level of Au loading as low as 0.1% wt. appeared to be efficient and prospective catalytic system for the green oxidation of alcohol. Most importantly, the results revealed that 0.1% Au/SiO2 might be the catalyst of choice with a wide scope of utility in the green oxidation of various structurally different alcohols as well as the non-activated aliphatic ones.

scholarly journals Cu(II) and Fe(III) Complexes Derived from N-Acetylpyrazine-2-Carbohydrazide as Efficient Catalysts Towards Neat Microwave Assisted Oxidation of Alcohols

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1053 ◽  
Author(s):  
Manas Sutradhar ◽  
Tannistha Roy Barman ◽  
Armando J. L. Pombeiro ◽  
Luísa M. D. R. S. Martins
Keyword(s):  
Catalytic Activity ◽  
Ir Spectroscopy ◽  
Maximum Yield ◽  
Catalytic Efficiency ◽  
Benzyl Alcohols ◽  
X Ray ◽  
X Ray Crystallography ◽  
Microwave Assisted ◽  
Tert Butyl Hydroperoxide ◽  
Oxidation Of Alcohols

The mononuclear Cu(II) complex [Cu((kNN′O-HL)(H2O)2] (1) was synthesized using N-acetylpyrazine-2-carbohydrazide (H2L) and characterized by elemental analysis, IR spectroscopy, ESI-MS and single crystal X-ray crystallography. Two Fe(III) complexes derived from the same ligand viz, mononuclear [Fe((kNN′O-HL)Cl2] (2) and the binuclear [Fe(kNN′O-HL)Cl(μ-OMe)]2 (3) (synthesized as reported earlier), were also used in this study. The catalytic activity of these three complexes (1–3) was examined towards the oxidation of alcohols using tert-butyl hydroperoxide (TBHP) as oxidising agent under solvent-free microwave irradiation conditions. Primary and secondary benzyl alcohols (benzyl alcohol and 1-phenylethanol), and secondary aliphatic alcohols (cyclohexanol) were used as model substrates for this study. A comparison of their catalytic efficiency was performed. Complex 1 exhibited the highest activity in the presence of TEMPO as promoter for the oxidation of 1-phenylethanol with a maximum yield of 91.3% of acetophenone.

scholarly journals Ultrafine Pd Nanoparticles Supported on Soft Nitriding Porous Carbon for Hydrogen Production from Hydrolytic Dehydrogenation of Dimethyl Amine-Borane

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1612
Author(s):  
Zhaoyu Wen ◽  
Qiong Fu ◽  
Jie Wu ◽  
Guangyin Fan
Keyword(s):  
Porous Carbon ◽  
High Performance ◽  
Hydrogen Generation ◽  
Pd Nanoparticles ◽  
Catalytic Performance ◽  
Pd Catalysts ◽  
Nano Catalyst ◽  
Dimethyl Amine ◽  
Catalytic Hydrogen ◽  
Hydrolysis Of

Simple and efficient synthesis of a nano-catalyst with an excellent catalytic property for hydrogen generation from hydrolysis of dimethyl amine-borane (DMAB) is a missing piece. Herein, effective and recycled palladium (Pd) nanoparticles (NPs) supported on soft nitriding porous carbon (NPC) are fabricated and applied for DMAB hydrolysis. It is discovered that the soft nitriding via a low-temperature urea-pretreatment induces abundant nitrogen-containing species on the NPC support, thus promoting the affinity of the Pd precursor and hindering the agglomeration of formed Pd NPs onto the NPC surface during the preparation process. Surface-clean Pd NPs with a diameter of sub-2.0 nm deposited on the NPC support (Pd/NPC) exhibit an outstanding catalytic performance with a turnover frequency (TOF) of 2758 h−1 toward DMAB hydrolysis, better than many previous reported Pd-based catalysts. It should be emphasized that the Pd/NPC also possesses a good stability without an obvious decrease in catalytic activity for DMAB hydrolysis in five successive recycling runs. This study provides a facile but efficient way for preparing high-performance Pd catalysts for catalytic hydrogen productions.

scholarly journals Silver nanoparticles supported on passivated silica: preparation and catalytic performance in alkyne semi-hydrogenation

2014 ◽  
Vol 43 (40) ◽  
pp. 15138-15142 ◽  
Author(s):  
Emma Oakton ◽  
Gianvito Vilé ◽  
Daniel S. Levine ◽  
Eva Zocher ◽  
David Baudouin ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Catalytic Activity ◽  
Catalytic Performance ◽  
Ag Particles

When X = SiMe3, small (2.1 ± 0.5 nm) densely packed silica-supported Ag particles can be prepared, which show an improved catalytic activity (per gram) whilst maintaining high alkene selectivity.

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