Efficient Aerobic Oxidation Of Alcohols Research Articles

Efficient aerobic oxidation of alcohols and sulfides using an M-doped (M: Mn and Ni) zinc oxide nanostructure

The generation of aldehydes and sulfoxides through selective oxidation process plays an essential role in different organic synthesis. However, using or toxic solvents under harsh reaction conditions leads to wastes and undesired by-products. With this background, ultrafast one-step fabrication of Ni/Mn doped-ZnO was developed under ultrasonic agitation for the first time. The resulting nanostructure was characterized by XRD, SEM, TEM, and BET analysis. According to data, a single-phase ZnO structure (wurtzite type) with uniform morphology, and acceptable surface area was obtained for the prepared nanocatalyst. Next, the catalytic activity of the nanostructure was investigated in aerobic oxidation of aliphatic and benzylic alcohols and sulfides. Notably, the present work is the first report of using ultrasound-engendered Ni/Mn doped-ZnO for selective aerobic oxidation reactions. It was found that the proposed nanostructure represented a novel chemical function for catalyzed alcohols and sulfides oxidation with excellent yields and selectivity without using any additives.

Efficient aerobic oxidation of alcohols to esters by acidified carbon nitride photocatalysts

Photocatalytic aerobic oxidation of alcohols for the direct synthesis of esters has received significant attention in recent years, but the relatively low efficiency and selectivity under visible light irradiation is the main challenge for their practical applications. Here, surface acidic sites were imparted onto metal-free heterogeneous photocatalysts by the protonation of carbon nitride (HMCN) to promote the activity for the esterification reaction through further adsorption and activation of the intermediate aldehyde. The activation of the substrate could be remarkably modulated through tuning the acidic sites on the surface of the photocatalyst, leading to a controllable reactivity of the catalytic reaction. The one-pot process for the direct aerobic oxidative esterification of alcohol exhibits high efficiency and selectivity under mild and additive-free conditions and the apparent quantum yield (AQY) of the photocatalytic esterification reaction is 0.41% at 420 nm. Moreover, a scalable photocatalytic process by the merging of a continuous flow system with the heterogeneous HMCN photocatalyst is demonstrated, combining high catalytic efficiency and stability at ambient temperatures and being promising for larger-scale applications.

Solvent and additive-free efficient aerobic oxidation of alcohols by a perovskite oxide-based heterogeneous catalyst

A perovskite oxide has been utilized for the solvent and additive-free heterogeneous oxidation of various alcohols.

Efficient selective oxidation of alcohols to carbonyl compounds catalyzed by Ru-terpyridine complexes with molecular oxygen

The oxidation of alcohols with molecular oxygen is a promising approach to produce corresponding carbonyl compounds. In this work, efficient aerobic oxidation of alcohols to carbonyl compounds catalyzed by ruthenium-terpyridine [(tpy-PhCH3)RuCl3] with isobutyraldehyde as co-substrate was developed. Various alcohols including primary and secondary alcohols are smoothly converted to corresponding carbonyl compounds in good yield. In a 100 times large-scale oxidation of benzyl alcohol, benzaldehyde was obtained with 92% isolated yield. Moreover, a plausible mechanism involving high-valence ruthenium species was proposed based on in situ UV–vis spectroscopy.

Efficient aerobic oxidation of alcohols to aldehydes and ketones using a ruthenium carbonyl complex of a tert-butyl-substituted tetramethylcyclopentadienyl ligand as catalyst

Tert-butyl-substituted tetramethylcyclopentadiene [C5HMe 4 Bu] was reacted with Ru3(CO)12 to prepare [(η5-C5Me 4 Bu)Ru(CO)(μ-CO)]2. The complex was characterized by IR, 1H NMR, 13C NMR, elemental analysis, and single-crystal X-ray diffraction. The complex was investigated as a catalyst in the aerobic oxidation of alcohols to the corresponding aldehydes and ketones in the presence of 2,2’,6,6’-tetramethylpiperidine N-oxide (TEMPO) as co-oxidant. The combination of [(η5-C5Me 4 Bu)Ru(CO)(μ-CO)]2 and TEMPO afforded an efficient catalytic system for the aerobic oxidation of a variety of primary and secondary alcohols, giving the corresponding carbonyl compounds in good-to-excellent yields.

Co-N-C catalysts synthesized by pyrolysis of Co-based deep eutectic solvents for aerobic oxidation of alcohols

DES derived Co-N-C composites were used for highly efficient aerobic oxidation of alcohols into the corresponding aldehydes and ketones.

Efficient aerobic oxidation of alcohols catalyzed by NiGa hydrotalcites in the absence of any additives

The surface Brønsted OH basic site on NiGa hydrotalcites was suggested to be the key active site for the oxidation.

Second-Order Biomimicry: In Situ Oxidative Self-Processing Converts Copper(I)/Diamine Precursor into a Highly Active Aerobic Oxidation Catalyst.

A homogeneous Cu-based catalyst system consisting of [Cu(MeCN)4]PF6, N,N′-di-tert-butylethylenediamine (DBED), and p-(N,N-dimethylamino)pyridine (DMAP) mediates efficient aerobic oxidation of alcohols. Mechanistic study of this reaction shows that the catalyst undergoes an in situ oxidative self-processing step, resulting in conversion of DBED into a nitroxyl that serves as an efficient cocatalyst for aerobic alcohol oxidation. Insights into this behavior are gained from kinetic studies, which reveal an induction period at the beginning of the reaction that correlates with the oxidative self-processing step, EPR spectroscopic analysis of the catalytic reaction mixture, which shows the buildup of the organic nitroxyl species during steady state turnover, and independent synthesis of oxygenated DBED derivatives, which are shown to serve as effective cocatalysts and eliminate the induction period in the reaction. The overall mechanism bears considerable resemblance to enzymatic reactivity. Most notable is the “oxygenase”-type self-processing step that mirrors generation of catalytic cofactors in enzymes via post-translational modification of amino acid side chains. This higher-order function within a synthetic catalyst system presents new opportunities for the discovery and development of biomimetic catalysts.

Nearly atomic precise gold nanoclusters on nickel-based layered double hydroxides for extraordinarily efficient aerobic oxidation of alcohols

Nearly atomic precise Au25/NixAl-LDH catalysts obtained via adsorption of Au25Capt18 onto predispersed NixAl-LDH following proper calcination show extraordinary alcohol oxidation property due to ultrafine Au cluster, ordered LDH layer and strong Au25–LDH synergy.

Fabrication of hierarchical composite microspheres of copper-doped Fe3O4@P4VP@ZIF-8 and their application in aerobic oxidation

Copper-doped Fe3O4@P4VP@ZIF-8 composite microspheres were fabricated for application in the highly efficient aerobic oxidation of alcohols and epoxidation of olefins.

ChemInform Abstract: Highly Efficient Aerobic Oxidation of Alcohols by Using Less‐Hindered Nitroxyl‐Radical/Copper Catalysis: Optimum Catalyst Combinations and Their Substrate Scope.

AbstractThe corresponding carbonyl compounds are efficiently obtained under mild reaction conditions from various alcohols, including highly hindered and heteroatom‐rich ones.

ChemInform Abstract: Green and Reusable Homogeneous Oxidative System with Ceric Ammonium Nitrate/[Imim‐PEG1000‐TEMPO] for Efficient Aerobic Oxidation of Alcohols and One‐Pot Synthesis of Benzimidazoles from Alcohols under Ambient Conditions.

AbstractThe environmentally friendly catalytic system is reusable without significant loss of activity after seven runs.

Highly efficient aerobic oxidation of alcohols by using less-hindered nitroxyl-radical/copper catalysis: optimum catalyst combinations and their substrate scope.

The oxidation of alcohols into their corresponding carbonyl compounds is one of the most fundamental transformations in organic chemistry. In our recent report, 2-azaadamantane N-oxyl (AZADO)/copper catalysis promoted the highly chemoselective aerobic oxidation of unprotected amino alcohols into amino carbonyl compounds. Herein, we investigated the extension of the promising AZADO/copper-catalyzed aerobic oxidation of alcohols to other types of alcohol. During close optimization of the reaction conditions by using various alcohols, we found that the optimum combination of nitroxyl radical, copper salt, and solution concentration was dependent on the type of substrate. Various alcohols, including highly hindered and heteroatom-rich ones, were efficiently oxidized into their corresponding carbonyl compounds under mild conditions with lower amounts of the catalysts.

Green and reusable homogeneous oxidative system with ceric ammonium nitrate/[Imim‐PEG1000‐TEMPO] for efficient aerobic oxidation of alcohols and one‐pot synthesis of benzimidazoles from alcohols under ambient conditions

An efficient and reusable catalytic system for aerobic oxidation of alcohols and one‐pot synthesis of benzimidazoles from alcohols with ceric ammonium nitrate and PEG1000–ionic liquid‐immobilized 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) is described. This system shows excellent activity and selectivity, affording the target products with good yields. Moreover, the catalytic system can be recycled and reused without significant loss of catalytic activity after seven runs. Copyright © 2014 John Wiley & Sons, Ltd.

Zirconia-Supported Ruthenium Catalyst for Efficient Aerobic Oxidation of Alcohols to Aldehydes

We have developed the supported ruthenium catalyst (Ru(OH)x/ZrO2) that shows highly efficient catalytic performance for the oxidation of activated, nonactivated, and heterocyclic alcohols with only 1 atm of molecular oxygen as a green oxidant. The ruthenium active site gave excellent aerobic alcohol oxidation reaction (turnover number (TON) = 63 000). The catalyst was easily recovered after the reaction and could be reused without a significant loss of its catalytic performance.

Efficient aerobic oxidation of alcohols using magnetically recoverable catalysts

A simple, highly efficient and mild catalytic aerobic oxidation of alcohol, in particularly benzoin was studied using iron oxide nanoparticles as a reusable catalyst. Moreover, benzyl was synthesized in large scale using inexpensive, readily available and environmentally friendly protocol in the presence of air. This novel and green methodology will allow further development not only in the geochemistry, but also in the oxidation of alcohols to replace expensive metals and corrosive reagents.

Bi-functionalized PEG1000 ionic liquid [Imim-PEG1000-TEMPO][CuCl2−]: an efficient and reusable catalytic system for solvent-free aerobic oxidation of alcohols

A reusable catalytic system for efficient aerobic oxidation of alcohols with bi-functionalized PEG1000 ionic liquid [Imim-PEG1000-TEMPO][CuCl2−] was described.

Layered double hydroxide supported gold nanoclusters by glutathione-capped Au nanoclusters precursor method for highly efficient aerobic oxidation of alcohols

M3Al-layered double hydroxide (LDH, M = Mg, Ni, Co) supported Au nanoclusters (AuNCs) catalysts have been prepared for the first time by using water-soluble glutathione-capped Au nanoclusters as precursor. Detailed characterizations show that the ultrafine Au nanoclusters (ca. 1.5 ± 0.6 nm) were well dispersed on the surface of LDH with a loading of Au below ∼0.23 wt% upon synergetic interaction between AuNCs and M3Al-LDH. AuNCs/Mg3Al-LDH-0.23 exhibits much higher catalytic performance for the oxidation of 1-phenylethanol in toluene than Au/Mg3Al-LDH(DP) by the conventional deposition precipitation method and can be applied for a wide range of alcohols without basic additives. This catalyst can also be reused without loss of activity or selectivity. The AuNCs/M(= Ni, Co)3Al-LDH catalysts present even higher alcohol oxidation activity than AuNCs/Mg3Al-LDH. Particularly, AuNCs/Ni3Al-LDH-0.22 exhibits the highest activity (46 500 h(-1)) for the aerobic oxidation of 1-phenylethanol under solvent-free conditions attributed to its strongest Au-support synergy. The excellent activity and stability of AuNCs/M3Al-LDH catalysts render these materials promising candidates for green base-free selective oxidation of alcohols by molecular oxygen.

Highly efficient and selective aerobic oxidation of alcohols in aqueous media by TEMPO-containing catalytic systems

The use of molecular oxygen as the oxidant and water as reaction medium is a charming research orientation in the oxidation of alcohols. In this communication, the efficient aerobic oxidation of alcohols to the corresponding carbonyl compounds in aqueous media has been achieved with TEMPO-containing catalytic systems. In the absence of base/acid, a 99% conversion and 94% selectivity for benzaldehyde were obtained for the oxidation of benzyl alcohol by TEMPO–Ce(IV)–NaNO2 in water. Moreover, the effects of quaternary ammonium salts and anionic surfactants were investigated. The aerobic selective oxidation of different non-heterocyclic alcohols in aqueous media was further investigated, and the moderate to high yields (45.5–98.0%) of products were obtained.

Cobalt Porphyrin Immobilized on Montmorillonite: A Highly Efficient and Reusable Catalyst for Aerobic Oxidation of Alcohols to Carbonyl Compounds

The highly efficient aerobic oxidation of alcohols to carbonyl compounds was achieved catalyzed by cationic meso -tetrakis (1-methyl-4-pyridyl, TM4PyP) metalloporphyrins immobilized in montmorillonite interlayers. Cobalt porphyrin (CoTM4PyP-MT) showed excellent activity and selectivity in the aerobic oxidation of benzyl alcohol, where 90% yield of benzaldehyde was obtained. CoTM4PyP-MT can be five times reused without significant loss of activity. 制备了蒙脱土负载的离子型四 (1-甲基-4-吡啶基) 金属卟啉, 并用于催化醇类氧化制备羰基化合物的反应中. 结果表明, 该催化剂表现出优异的活性和产物选择性, 其中在苯甲醇氧化反应中, 苯甲醛收率可达 90%, 且连续重复使用 5 次后, 其活性未见明显下降. Efficient aerobic oxidation of alcohols catalyzed by cobalt porphyrin immobilized into montmorillonite was achieved. The catalyst could be five times consecutively reused.