Catalyst For Selective Aerobic Oxidation Research Articles

Bimetallic Cu-Pd Nanoparticles Supported on Bio-silica as an Efficient Catalyst for Selective Aerobic Oxidation of Benzylic Alcohols

A new bimetallic heterogeneous catalyst consisting of copper and palladium nanoparticles supported on bio-silica is presented. The use of TEMPO as co-catalyst allowed the aerobic oxidation of primary benzylic alcohols into the corresponding aldehydes with excellent selectivity and good activity. The methodology could be applied to the oxidation of allylic and heterobenzylic alcohols. The catalyst is easy to prepare from commercial starting materials and can be recovered and reused without apparent loss of activity.

Natural hydroxyapatite‐supported MnO2: a green heterogeneous catalyst for selective aerobic oxidation of alkylarenes and alcohols

Natural hydroxyapatite‐supported MnO2 (MnO2@NHAp) was easily prepared in situ from reduction of potassium permanganate with natural hydroxyapatite derived from cow bones in water at room temperature, and its structure was characterized using flame atomic absorption spectroscopy, X‐ray diffraction, thermogravimetric analysis, scanning electron microscopy and energy dispersive spectroscopy. The catalytic activity of the synthesized catalyst was investigated for the aerobic oxidation of alkylarenes and alcohols. MnO2@NHAp shows excellent catalytic performance for the oxidation of alkylarenes and alcohols to their corresponding carbonyl compounds without using any other oxidizing agent. This catalyst can be readily recycled and reused for several runs without any significant loss of efficiency. Copyright © 2016 John Wiley & Sons, Ltd.

ChemInform Abstract: Cobalt‐Chitosan: Magnetic and Biodegradable Heterogeneous Catalyst for Selective Aerobic Oxidation of Alkyl Arenes and Alcohols.

AbstractThe novel cobalt—chitosan compound is used as a magnetic heterogeneous catalyst for the aerobic oxidation of alkyl arenes and alcohols.

P-Doped Porous Carbon as Metal Free Catalysts for Selective Aerobic Oxidation with an Unexpected Mechanism.

An extremely simple and rapid (seconds) approach is reported to directly synthesize gram quantities of P-doped graphitic porous carbon materials with controlled P bond configuration. For the first time, it is demonstrated that the P-doped carbon materials can be used as a selective metal free catalyst for aerobic oxidation reactions. The work function of P-doped carbon materials, its connectivity to the P bond configuration, and the correlation with its catalytic efficiency are studied and established. In direct contrast to N-doped graphene, the P-doped carbon materials with higher work function show high activity in catalytic aerobic oxidation. The selectivity trend for the electron donating and withdrawing properties of the functional groups attached to the aromatic ring of benzyl alcohols is also different from other metal free carbon based catalysts. A unique catalytic mechanism is demonstrated, which differs from both GO and N-doped graphene obtained by high temperature nitrification. The unique and unexpected catalytic pathway endows the P-doped materials with not only good catalytic efficiency but also recyclability. This, combined with a rapid, energy saving approach that permits fabrication on a large scale, suggests that the P-doped porous materials are promising materials for "green catalysis" due to their higher theoretical surface area, sustainability, environmental friendliness, and low cost.

Natural hydroxyapatite supported cobalt tetrasulfophthalocyanine: a green, renewable and biomaterial-based heterogeneous catalyst for selective aerobic oxidation of alkyl arenes and alcohols

Natural hydroxyapatite supported cobalt tetrasulfophthalocyanine (CoTSPc-NHAp) as a green, renewable and biomaterial-based heterogeneous catalyst promotes aerobic oxidation of alkyl arenes and alcohols.

Cobalt-chitosan: Magnetic and biodegradable heterogeneous catalyst for selective aerobic oxidation of alkyl arenes and alcohols

A novel and biodegradable cobalt-chitosan as a magnetic heterogeneous catalyst was synthesized and characterized by XPS, FT-IR, EDX and TEM. Catalytic performance of cobalt- chitosan was tested by aerobic oxidation of alkyl arenes and alcohols. The results show that the catalyst exhibits excellent conversion for selective aerobic oxidation of various alkyl arenes, primary and secondary alcohols with air as the only oxidant. The catalyst can be easily separated by magnetic devices and reused for 5 runs without appreciable loss of activity. A biodegradable cobalt-chitosan as a magnetic heterogeneous catalyst was synthesized. Catalytic performance of cobalt-chitosan was tested by aerobic oxidation of alkyl arenes and alcohols. The results show that the catalyst exhibits excellent conversion for selective aerobic oxidation of alkyl arenes and alcohols with air as the only oxidant.

ChemInform Abstract: Gold Nanoparticles Supported on Three‐Dimensional Nitrogen‐Doped Graphene: An Efficient Catalyst for Selective Aerobic Oxidation of Hydrocarbons under Mild Conditions.

The development of efficient and selective aerobic oxidation of alkylarenes to form more functional compounds by heterogeneously catalysed routes still presents a great challenge in the fine chemical industry and is a major research topic. In this work, gold nanoparticles supported on three-dimensional nitrogen-doped graphene-based frameworks (Au NPs@3D-(N)GFs) were successfully synthesized and found to have an impressive performance as bifunctional catalysts (nitrogen dopant as base and gold nanoparticles as active site) in the controlled oxidation of alkylarenes. The catalyst was found to be a simple bench top, stable, recyclable and selective catalytic system for the aerobic oxidation of various types of alkylarenes into their corresponding ketones at room temperature under environmentally friendly conditions with good yields and high selectivity. Copyright © 2015 John Wiley & Sons, Ltd.

Gold nanoparticles supported on three‐dimensional nitrogen‐doped graphene: an efficient catalyst for selective aerobic oxidation of hydrocarbons under mild conditions

The development of efficient and selective aerobic oxidation of alkylarenes to form more functional compounds by heterogeneously catalysed routes still presents a great challenge in the fine chemical industry and is a major research topic. In this work, gold nanoparticles supported on three‐dimensional nitrogen‐doped graphene‐based frameworks (Au NPs@3D‐(N)GFs) were successfully synthesized and found to have an impressive performance as bifunctional catalysts (nitrogen dopant as base and gold nanoparticles as active site) in the controlled oxidation of alkylarenes. The catalyst was found to be a simple bench top, stable, recyclable and selective catalytic system for the aerobic oxidation of various types of alkylarenes into their corresponding ketones at room temperature under environmentally friendly conditions with good yields and high selectivity. Copyright © 2015 John Wiley & Sons, Ltd.

Nanocrystalline cellulose grafted phthalocyanine: a heterogeneous catalyst for selective aerobic oxidation of alcohols and alkyl arenes at room temperature in a green solvent

A Cu-tetrasulfonate-phthalocyanine was conjugated to cationic cellulose nanocrystals which serve as a heterogeneous based catalyst for aerobic oxidation of alcohols and alkyl arenes at room temperature in aqueous medium.

Keggin type transition metal substituted phosphomolybdates: heterogeneous catalysts for selective aerobic oxidation of alcohols and alkenes under solvent free condition

Environmentally benign oxidation of alcohols and alkenes over transition metal substituted phosphomolybdates with molecular oxygen as an oxidant and TBHP as an initiator was carried out. The influence of different parameters on the conversion as well as the selectivity was investigated. All the catalysts showed good catalytic activity with excellent selectivity for the desired products as well as a higher TON. The system not only catalyzes the reaction but also avoids the use of organic solvents as it was carried out under solvent free conditions. Moreover, the catalysts could be recovered and reused four times without a significant loss in their activity and selectivity. A probable reaction mechanism was also proposed for the oxidation of alcohols and alkenes.

Aqueous aerobic oxidation of alkyl arenes and alcohols catalyzed by copper(II) phthalocyanine supported on three-dimensional nitrogen-doped graphene at room temperature.

Copper(ii) tetrasulfophthalocyanine supported on three-dimensional nitrogen-doped graphene-based frameworks was synthesized and introduced as a bifunctional catalyst for selective aerobic oxidation of alkyl arenes and alcohols to the corresponding carbonyl compounds. The ease of catalyst separation, high turnover, low catalyst loading and recyclability could potentially render it applicable in industrial setting.

Platinum/Gold Alloy Nanoparticles-Supported Hydrotalcite Catalyst for Selective Aerobic Oxidation of Polyols in Base-Free Aqueous Solution at Room Temperature

As-prepared platinum/gold alloy nanoparticles-supported hydrotalcites (PtxAuy–starch/HTs) by using a soluble starch as a green reducing and a stabilizing agent are found to be truly effective heterogeneous catalysts for the selective aerobic oxidation of glycerol (GLY) and 1,2-propanediol (PG) in base-free aqueous solution using molecular oxygen in atmospheric pressure at room temperature. The PtxAuy–starch/HTs exhibited higher selectivities for oxidation of the primary hydroxyl group in GLY and PG toward glyceric acid (GA) and lactic acid (LA), respectively, with molecular oxygen in aqueous solution than those reactions over monometallic Pt–starch/HT or Au–starch/HT. Pt60Au40–starch/HT was found to be the most active catalyst for selective aerobic oxidation of polyols. It showed 73% GLY conversion with 57% GA yield and 63% PG conversion with 47% LA yield and retained high selectivity in recycling experiments. XRD patterns of the PtxAuy–starch NPs indicated the d-spacing of Pt atoms was changed by alloyin...

Manganese octahedral molecular sieve (OMS-2) catalysts for selective aerobic oxidation of thiols to disulfides

Selective aerobic oxidation of thiols to disulfides without any over oxidized products is studied using cryptomelane type manganese oxides (K-OMS-2) with a tunnel structure as catalysts. Using K-OMS-2 prepared by different synthetic procedures, complete conversion was obtained under air atmosphere without generating any overoxidized products. K-OMS-2 prepared by solvent free method (K-OMS-2SF) with the highest surface area (155±1m2/g) gave complete conversion, while materials prepared using hydrothermal method (K-OMS-2HY) with the lowest surface area (44±1m2/g) gave only 18% conversion at room temperature. Selective poisoning of the acid sites suggests that Lewis acid sites are the dominating active site during the reaction. Effects of surface area of the catalyst, solvent polarity, substrate effect, catalyst recyclability and temperature were studied. The catalyst could be recovered in the active form after the reaction without significant structural changes. The characterization of the catalyst using XRD, SEM, TGA, BET, TEM, and FT-IR are reported. The process developed is environmentally benign and is indeed heterogeneous.

Activated carbon-supported ruthenium as an efficient catalyst for selective aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

The aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) was performed on an activated carbon-supported ruthenium (Ru/C) catalyst. The excellent DFF yield of 95.8% was achieved at 383 K and O 2 pressure 2.0 MPa in toluene. It exhibited superior activity and DFF selectivity than other C-supported noble metals (i.e. Pt, Rh, Pd, and Au) with comparable nanoparticle size. The Ru/C catalyst was stable and can be recycled by a simple hydrothermal treatment. Moreover, the product distribution in the HMF oxidation on Ru/C can be tuned by the use of water as solvent and the addition of hydrotalcite, giving either 5-formyl-2-furancarboxylic acid or 2,5-furandicarboxylic acid as the dominant product. 在活性炭负载金属钌(Ru/C)催化剂上实现了5-羟甲基糠醛的高效选择氧化. 以甲苯为反应溶剂, 在383 K和2.0 MPa O 2 的反应条件下, 2,5-呋喃二甲醛(DFF)收率高达95.8%. 与活性炭负载的具有相似粒径的Pt, Rh, Pd, Au等其它贵金属催化剂相比, Ru/C具有更加优良的活性和DFF选择性. 同时Ru/C催化剂结构稳定, 具有良好的重复使用性能. 在相似的反应条件下, 采用水代替甲苯作为溶剂, 同时添加少量水滑石固体碱, 可便捷地将主要产物从DFF调变为5-甲酰基-2-呋喃甲酸或2,5-呋喃二甲酸, 显示出Ru/C催化剂在控制5-羟甲基糠醛选择氧化反应产物方面的优异性能. Ru/C is an effective and recyclable catalyst in the aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF), affording a high DFF yield of 95.8% in toluene.

Gold Catalysts for Selective Aerobic Oxidation of the Lignan Hydroxymatairesinol to Oxomatairesinol: Catalyst Deactivation and Regeneration

The lignan oxomatairesinol was synthesized from the biomass-derived lignan hydroxymatairesinol via selective aerobic oxidation over a heterogeneous gold catalyst. The catalyst was prepared by direct ion-exchange and characterized by XRD, TEM and ICP-OES methods. The reaction was carried out at 70 °C and atmospheric pressure in a semi-batch reactor. To reveal the origin of catalyst deactivation, spent catalysts were studied by TEM, XRD, nitrogen physisorption, ICP-OES, TPO, and DSC-TGA techniques. Several regeneration procedures were applied—extraction by several solvents and calcinations in the oxidizing atmosphere. The former one was found to be the most effective way for the catalyst regeneration.

ChemInform Abstract: Synthesis of Bimagnetic Ionic Liquid and Application for Selective Aerobic Oxidation of Aromatic Alcohols under Mild Conditions.

The first bimagnetic ionic liquid based on Fe and TEMPO with cooperative functionalities not only exhibited strong paramagnetic behaviour at room temperature under an applied magnetic field of 5000 Oe but also proved to be an effective catalyst for selective aerobic oxidation of aromatic alcohols under mild and clean conditions.

Influence of support surface basicity and gold particle size on catalytic activity of Au/γ-AlOOH and Au/γ-Al2O3 catalyst in aerobic oxidation of α,ω-diols to lactones

Gold catalysts on inert support γ-AlOOH and γ-Al2O3 were used as catalysts for selective aerobic oxidation of α,ω-diols to the corresponding lactones. The support crystal phase and basicity can be adjusted by calcination. Support calcined at below 573K is in the γ-AlOOH phase and when calcined at above 773K it is in the form of γ-Al2O3. There are only weak or medium basic sites on γ-Al2O3, while γ-AlOOH has strong or medium basic sites. Both support surface acidic–basic properties and gold particle size have influence on the activity and selectivity of the catalysts. Highly active catalysts can be obtained on both of the support, and from the characterization results it was found that the strong basic sites of γ-AlOOH were beneficial for the reaction, while selectivity would be sacrificed due to the hydrolysis of the product or further oxidation to acids under basic conditions. By loading gold onto γ-Al2O3, average gold particle size small as 3.8nm can be obtained and it gives higher activity and selectivity than Au/γ-AlOOH.

Synthesis of bimagnetic ionic liquid and application for selective aerobic oxidation of aromatic alcohols under mild conditions

The first bimagnetic ionic liquid based on Fe and TEMPO with cooperative functionalities not only exhibited strong paramagnetic behaviour at room temperature under an applied magnetic field of 5000 Oe but also proved to be an effective catalyst for selective aerobic oxidation of aromatic alcohols under mild and clean conditions.

ChemInform Abstract: Creation of a Monomeric Ruthenium Species on the Surface of Micro‐Size Copper Hydrogen Phosphate: An Active Heterogeneous Catalyst for Selective Aerobic Oxidation of Alcohols.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Creation of a Monomeric Ruthenium Species on the Surface of Micro‐Size Copper Hydrogen Phosphate: An Active Heterogeneous Catalyst for Selective Aerobic Oxidation of Alcohols

AbstractA new micro‐size copper hydrogen phosphate (CHP) synthesized by the emulsion method combined with a monomeric ruthenium species was found to be a very effective catalyst for the selective oxidation of alcohols. Several kinds of alcohols were transformed into the corresponding aldehydes or ketones over the RuCHP catalyst by oxygen under very mild conditions. The results showed that the CHP material was perfect as a catalyst support due to its high ion‐exchange ability and adsorption capacity.