Aerobic Oxidation Of Alcohols Research Articles

Metal-free aerobic oxidation of benzyl alcohols over the selective N, P dual-doped hollow carbon sphere as the efficient and sustainable heterogeneous catalyst under mild reaction condition

Nitrogen and phosphorous dual-doped carbon materials are one the promising candidate for the ecofriendly and metal-free heterogeneous catalytic systems owing to the abundance activated sites which is caused by doping the heteroatoms in the carbonaceous materials. The N, P-dual-doped carbon hollow sphere (HPNC-700) precursor prepared via template-assisted strategy by using the SiO 2 as the hard template in the presence of glucose, phosphoric acid and melamine as C, P, and N source, respectively. The resultant catalyst was obtained by pyrolyzing process at 700 °C under N 2 atmosphere by adding the NaOH solution to remove the template. According to various physicochemical analysis including FE-SEM, TEM, XRD, XPS, and Raman spectroscopy, the catalyst exhibited the desired and acceptable properties. So, based on these outcomes, the catalytic efficiency of the HPNC-700 was evaluated in the selective aerobic oxidation of benzyl alcohols. As expected, the HPNC-700 represented the acceptable proficiency in the mentioned reaction with high TOF value, full conversion (>99%) and also the notable recyclability. • P, N-dual doped carbon hollow spheres were designed for selective aerobic oxidation of benzyl alcohols. • SiO 2 spheres were used as the hard templet to synthesis the hollow spheres. • The heterogeneous metal-free HPNC-700 catalyst represents the high efficiency toward oxidation reaction at mild condition. • The more defects in the carbonaceous caused the more efficiency in the catalytic performance. • By doping The P and N in the sructure of carbon, the activated sites were developed in the synthesized catalyst.

The solvent-free and aerobic oxidation of benzyl alcohol catalyzed by Pd supported on carbon nitride/CeO2 composites

Palladium catalysts supported on carbon nitride/ceria composites showed superior activity during the solvent-free and aerobic oxidation of benzyl alcohol to benzaldehyde.

Aerobic oxidation of vanillyl alcohol to vanillin catalyzed by air-stable and recyclable copper complex and TEMPO under base-free conditions

An air-stable, recyclable, and sustainable copper catalyst was efficiently utilized for the aerobic oxidation of biomass model compound vanillyl alcohol to the important aroma compound vanillin under green conditions.

Oil foams stabilized by POSS/organosilica particle assemblies: application for aerobic oxidation of aromatic alcohols.

A novel amphiphilic polyhedral oligomeric silsesquioxane (POSS) with surfactant-like behavior was synthesized. By combining this new POSS, used as a frother, with surface-active catalytic organosilica particles, used as a stabilizer, we designed a dual particle system able to generate foams in pure organic solvents. Tunable foamability and foam stability were achieved in a variety of organic solvents by simply adjusting the POSS concentration. As a result, the catalytic activity was drastically boosted in the aerobic oxidation of pure aromatic alcohols under 1 bar O2 pressure. Particles were conveniently recycled with high foamability and the catalytic efficiency was maintained for at least 7 consecutive runs.

Catalytic behaviour of the Cu(i)/L/TEMPO system for aerobic oxidation of alcohols - a kinetic and predictive model.

Here, we disclose a new copper(i)-Schiff base complex series for selective oxidation of primary alcohols to aldehydes under benign conditions. The catalytic protocol involves 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), N-methylimidazole (NMI), ambient air, acetonitrile, and room temperature. This system provides a straightforward and rapid pathway to a series of Schiff bases, particularly, the copper(i) complexes bearing the substituted (furan-2-yl)imine bases N-(4-fluorophenyl)-1-(furan-2-yl)methanimine (L2) and N-(2-fluoro-4-nitrophenyl)-1-(furan-2-yl)methanimine (L4) have shown excellent yields. Both benzylic and aliphatic alcohols were converted to aldehydes selectively with 99% yield (in 1–2 h) and 96% yield (in 16 h). The mechanistic studies via kinetic analysis of all components demonstrate that the ligand type plays a key role in reaction rate. The basicity of the ligand increases the electron density of the metal center, which leads to higher oxidation reactivity. The Hammett plot shows that the key step does not involve H-abstraction. Additionally, a generalized additive model (GAM, including random effect) showed that it was possible to correlate reaction composition with catalytic activity, ligand structure, and substrate behavior. This can be developed in the form of a predictive model bearing in mind numerous reactions to be performed or in order to produce a massive data-set of this type of oxidation reaction. The predictive model will act as a useful tool towards understanding the key steps in catalytic oxidation through dimensional optimization while reducing the screening of statistically poor active catalysis.

Boosting the catalytic behavior and stability of a gold catalyst with structure regulated by ceria.

In this work, a series of colloidal gold nanoparticles with controllable sizes were anchored on carbon nanotubes (CNT) for the aerobic oxidation of benzyl alcohol. The intrinsic influence of Au particles on the catalytic behavior was unraveled based on different nanoscale-gold systems. The Au/CNT-A sample with smaller Au sizes deserved a faster reaction rate, mainly resulting from the higher dispersion degree (23.5%) of Au with the available exposed sites contributed by small gold particles. However, monometallic Au/CNT samples lacked long-term stability. CeO2 was herein decorated to regulate the chemical and surface structure of the Au/CNT. An appropriate CeO2 content tuned the sizes and chemical states of Au by electron delivery with better metal dispersion. Small CeO2 crystals that were preferentially neighboring the Au particles facilitated the generation of Au–CeO2 interfaces, and benefited the continuous supplementation of oxygen species. The collaborative functions between the size effect and surface chemistry accounted for the higher benzaldehyde yield and sustainably stepped-up reaction rates by Au-Ce5/CNT with 5 wt% CeO2.

β-MnO2 nanoparticles as heterogenous catalysts for aerobic oxidative transformation of alcohols to carbonyl compounds, nitriles, and amides

β-MnO2 nanoparticles exhibit high catalytic performance for the aerobic oxidation of various aromatic, allylic, and heteroaromatic alcohols and one-pot tandem oxidation of alcohols to nitriles and amides in the presence of NH3.

The design of experiments (DoE) in optimization of an aerobic flow Pd-catalyzed oxidation of alcohol towards an important aldehyde precursor in the synthesis of phosphatidylinositide 3-kinase inhibitor (CPL302415).

Herein, we describe the development of a green, scalable flow Pd-catalyzed aerobic oxidation for the key step in the synthesis of CPL302415, which is a new PI3Kδ inhibitor. Applying this environmental-friendly, sustainable catalytic oxidation we significantly increased product yield (up to 84%) and by eliminating of workup step, we improved the waste index and E factor (up to 0.13) in comparison with the stoichiometric synthesis. The process was optimized by using the DoE approach.

Insight into Au/ZnO catalyzed aerobic benzyl alcohol oxidation by modulation–excitation attenuated total reflection IR spectroscopy

The chemisorbed or dissociated oxygen species is associated with the catalytic activity in alcohol oxidation catalyzed by Au/ZnO catalysts.

Copper/TEMPO-catalyzed continuous aerobic alcohol oxidation in a micro-packed bed reactor

A micro-packed bed reactor has been developed to demonstrate aerobic oxidation of alcohols to aldehydes, utilizing green oxidant O2 and effective Cu/TEMPO-catalyzed system.

Hierarchical Co@C-N synthesized by the confined pyrolysis of ionic liquid@metal–organic frameworks for the aerobic oxidation of alcohols

Co@C-N with hierarchical pores and highly active sites is synthesized by the pyrolysis of an ionic liquid@metal–organic framework.

Unsymmetrical PEG-substituted tris(triazolyl)amines as bi-functional surfactants for copper-catalyzed aerobic oxidation of alcohols in water

Unsymmetric tris(triazolyl)amine surfactants with mPEG550 and mPEG2000 substituents efficiently promote copper-catalyzed alcohol oxidation in water.

Aerobic oxidation of alcohols enabled by nitrogen-doped copper nanoparticle catalysts

Heterogeneous nitrogen-doped carbon-incarcerated copper nanoparticle catalysts have been developed.

Nitroxyl radical-containing flexible porous coordination polymer for controllable size-aelective aerobic oxidation of alcohols.

The ability of flexible porous coordination polymers (PCPs) to change their structure in response to various stimuli has not been exploited in the design of tunable-selectivity catalysts. Herein, we make use of this ability and prepare nitroxyl radical-containing flexible PCP that can reversibly switch between large- and contracted-pore configurations in response to solvent change and thus promote the controllable size-selective aerobic oxidation of alcohols.

Selective iron-catalyzed aerobic oxidation of alcohols in water to carboxylic acids mediated by additives

The iron catalyst (POM-Fe) could combine with chloride ions to form a supramolecular aggregate FeMo6·Cl, which was used in the oxidation of alcohols to carboxylic acids under mild conditions and can tolerate 40 substrates with moderate to high yield.

Non -covalent LDH/MOF composite formation: a new approach in sustainability for solvent-dependent photocatalytic aerobic alcohol oxidation

An FeIII-based metal–organic framework denoted as MIL-100(Fe) coated with cobalt–aluminium layered double hydroxide (CoAl-LDH) nanoplates has been synthesized.

A “universal” catalyst for aerobic oxidations to synthesize (hetero)aromatic aldehydes, ketones, esters, acids, nitriles, and amides

<h2>Summary</h2> Functionalized (hetero)aromatic compounds are indispensable chemicals widely used in basic and applied sciences. Among these, especially aromatic aldehydes, ketones, carboxylic acids, esters, nitriles, and amides represent valuable fine and bulk chemicals, which are used in chemical, pharmaceutical, agrochemical, and material industries. For their synthesis, catalytic aerobic oxidation of alcohols constitutes a green, sustainable, and cost-effective process, which should ideally make use of active and selective 3D metals. Here, we report the preparation of graphitic layers encapsulated in Co-nanoparticles by pyrolysis of cobalt-piperazine-tartaric acid complex on carbon as a most general oxidation catalyst. This unique material allows for the synthesis of simple, functionalized, and structurally diverse (hetero)aromatic aldehydes, ketones, carboxylic acids, esters, nitriles, and amides from alcohols in excellent yields in the presence of air.

A Novel Pd-P Nano-Alloy Supported on Functionalized Silica for Catalytic Aerobic Oxidation of Benzyl Alcohol

Catalytic aerobic oxidation of benzyl alcohol (BnOH) to benzaldehyde (PhCHO) over supported noble metal catalysts has grabbed the attention of researchers due to the critical role of PhCHO in numerous industrial syntheses. In the present study, a novel catalyst, Pd-P alloy supported on aminopropyl-functionalized mesoporous silica (NH2-SiO2), was prepared through in situ reduction and characterized by BET-BJH analysis, SEM, TEM, XRD, FTIR, TG-DTA, and XPS. Chemical properties and catalytic performance of Pd-P/NH2-SiO2 were compared with those of Pd° nanoparticles (NPs) deposited on the same support. Over Pd-P/NH2-SiO2, the BnOH conversion to PhCHO was much higher than over Pd°/NH2-SiO2, and significantly influenced by the nature of solvent, reaching 57% in toluene at 111 °C, with 63% selectivity. Using pure oxygen as an oxidant in the same conditions, the BnOH conversion increased up to 78%, with 66% selectivity. The role of phosphorous in improving the activity may consist of the strong interaction with Pd that favours metal dispersion and lowers Pd electron density.

Reusable homogeneous metal- and additive-free photocatalyst for high-performance aerobic oxidation of alcohols to carboxylic acids

How to realize the recycling of homogeneous catalysts has been a great challenge for chemists. In this background, a new pyridinium compound was synthesized and applied in selective photocatalytic oxidation. This photocatalytic system is advantageous in accelerating the transformation of alcohols into acids by two consecutive routes, including (1) photocatalytic oxidation of alcohols to aldehydes; (2) photocatalytic oxidation and autoxidation of aldehydes to acids. By activating molecular oxygen into •O2− and 1O2, the system displays advantages of high efficiency and simplicity, as well as environment-friendly nature without metals or additives. Attractively, this compound as a homogeneous catalyst can be reused by direct filtration of products profiting from its high performance and stability. The present work develops a new approach to achieve an efficient and recyclable aerobic oxidation of alcohols into acids by using pyridinium-based photocatalysts and provides a valuable insight into the separation and recycling of homogeneous catalysts for economic compatibility and industrial application.

Effect of oxy-vanadium (IV) and oxy-zirconium (IV) ions in O,N-bidentate arylhydrazone complexes on their catalytic and biological potentials that supported via computerized usages

BackgroundBased on the high coordination behavior of arylhydrazones, as pincer chelating agents, the purpose of this research is to study the synthesis, characterization and reactivity of two mononuclear oxy-vanadium (IV) and oxy- zirconium (IV) complexes (VO(ALz)2 and ZrO(ALz)2, respectively) of O,N-monobasic bidenate arylhydazone derivative (2-((2-(2,4-dinitrophenyl) hydrazineylidene)methyl)-4-nitrophenol, HALz). MethodsVarious spectroscopic methods were applied to characterize the chemical structures of the ligand and their O=M4+-complexes (NMR, UV-Vis., Mass and IR spectra). Their reactivity was estimated catalytically and biologically. The significant findingsHere, the function of the oxy-highly charged metal ion of (O=M4+: V4+ and Zr4+-ions) on reactivity of their arylhydrazone complexes was reported catalytically and biologically. The differentiation in the catalytic features of VO(ALz)2 and ZrO(ALz)2 depends on the type of O=M4+ ion, which examined in the aerobic oxidation of benzyl alcohol using tert-butyl hydroperoxide (tBuOOH) under solvent free atmosphere at 90 °C (the optimized conditions). VO(ALz)2 exhibited little more progressed catalytic potential (2 h with 89% yield of benzaldehyde) over that of ZrO(ALz)2 (6 h with 82% yield of benzaldehyde). The electron-oxygen gain/loss of O=M4+ ion in its complex catalyst displayed the major role for progressing of its catalytic potential. The catalytic oxidation of secondary alcohols to their corresponded ketones was performed with VO(ALz)2 and ZrO(ALz)2 catalysts. A mechanistic pathway was proposed depending on via DFT approach and on spectroscopic aspects.The biological action of HALz, VO(ALz)2 and ZrO(ALz)2 were studied within their binding action towards ctDNA (through UV–Visible spectroscopy and viscosity measuring) depending on the type of O=M4+ ion in their reagents. The interaction of HALz, VO(ALz)2 and ZrO(ALz)2 and was evaluated with the binding constant (2.85, 6.07 and 5.42 × 105 mol−1 dm3, respectively), which referred to their high reactivity towards ctDNA. In addition, the values of Gibbs’ free energy supported their ctNDA interaction (-31.11, -32.99 and -32.71 kJ mol−1, respectively). Both V4+ and Zr4+ ions in their complexes promoted their reactivity as antioxidant, antimicrobial and anticancer reagents more that their uncoordinated HALz ligand. The interaction with DNA-pockets was investigated through in-silico ways regarding pharmacophore query and MOE-docking module, to strengthen the biological screening. Considerably, the current MO-complexes with their effective antimicrobial, antioxidant, and cytotoxicity activity would be probably appraised for further medicinal and pharmaceutical applications.