Oxidation Of Different Alcohols Research Articles

Oxidation of 5-Hydroxymethylfurfural into 2,5-Diformylfuran on Alkali Doped Ru/C Catalysts. Electron Properties of Ruthenium Species as Descriptor of Catalytic Activity.

Selective aerobic oxidation of 5-hydroxymethylfurfural into 2,5-diformylfuran has been achieved on alkali doped Ru/C catalyst. Optimization of Ru metal nanoparticles, as well as the nature and amount of the alkali dopant have been performed. The results showed that doping the Ru/C catalyst with controlled amount of potassium increases the catalytic activity, 2.5 fold with respect to the non-doped sample. Spectroscopic studies showed that these differences in activity can be attributed to a different oxidation reaction mechanism associated to the presence of electron rich Ru species in the promoted sample that facilitate the dissociation of O2, while prevents the oxidation of the metal. The Ru/C-K doped catalyst resulted very stable against leaching and metal sintering, being possible the reuse over several consecutive runs. Moreover, the catalyst could be successfully applied to the oxidation of different alcohols.

MIL-47(V)-derived carbon-doped vanadium oxide for selective oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran.

The development and transformation of biomass-derived platform compounds is a sustainable way to deal with the fossil fuel crisis. 5-Hydroxymethylfurfural (HMF) can be reduced or oxidized to produce many high-value compounds; however, it is challenging to effectively produce 2,5-diformylfuran (DFF) due to overoxidation. In this work, a carbon-doped V2O5 (C-V2O5) material was obtained through pyrolysis of MIL-47(V) nanorods, a typical metal-organic framework material. The X-ray diffraction patterns and X-ray photoelectron spectra showed that the graphitized carbon species were incorporated in C-V2O5. High-efficiency HMF oxidation, high specific selectivity for DFF and excellent recycling could be achieved with the C-V2O5 catalyst. Fourier-transform infrared spectroscopy combined with density functional theory (DFT) calculation revealed that graphitized carbon weakens the VO bond and promotes the formation of oxygen vacancies in C-V2O5, thus improving the catalytic activity in the oxidation of furfuryl alcohols. The V4+ induced by oxygen vacancies will be oxidized by O2 to form V5+, so that the cycle can be realized. It exhibits remarkable selectivity in the oxidation of different alcohols produced from biomass based on the relatively constant active sites in C-V2O5.

Ionic liquid/Mn complex immobilized on phenylene based periodic mesoporous organosilica: An efficient and reusable nanocatalyst for green oxidation of alcohols

A novel bifunctional periodic mesoporous organosilica with ionic liquid and phenylene framework supported manganese (BPMO-Ph-IL/Mn) was synthesized, characterized and its catalytic application was investigated. The BPMO-Ph-IL/Mn nanocatalyst was prepared through grafting of ionic liquid on a phenylene based PMO followed by treatment with manganese nitrate. The designed BPMO-Ph-IL/Mn catalyst was characterized using FT-IR, PXRD, TEM, EDX and N2 adsorption–desorption analyses. This was used as an efficient catalyst for selective oxidation of different alcohols. The BPMO-Ph-IL/Mn catalyst was recovered and reused for at least five times without a significant decrease in its efficiency.

Solvent-free selective oxidation of alcohols with tert-butyl hydroperoxide catalyzed by palladium(II) isatin Schiff base complex supported into three-dimensional mesoporous silica KIT-6

In this work, the catalytic activity of a palladium(II) isatin Schiff base complex immobilized into mesoporous silica KIT-6 (Pd-isatin Schiff base@KIT-6) was studied for the oxidation of different alcohols with tert-butyl hydroperoxide (TBHP, 70% aqueous solution) as an oxidant under solvent-free conditions. To find the suitable reaction conditions, the effect of essential factors including the solvent, temperature, catalyst amount and kind of oxidant on the oxidation of benzyl alcohol was explored. The results showed that in this catalytic system, the corresponding aldehydes and ketones were obtained with high to excellent yields at 50 °C without the formation of carboxylic acids as by-products. The catalyst was easily recovered by simple filtration and reused in five subsequent reaction cycles without any significant loss in the catalytic activity. Moreover, the comparison of the Fourier transform infrared (FT-IR) spectrum, X-ray diffraction (XRD) pattern, scanning and transmission electron microscopy (SEM and TEM) images of the used catalyst with a fresh one showed that the structure of the Pd-isatin Schiff base@KIT-6 catalyst remained intact after five times of reuse.

Dual stimuli-responsive silver nanoparticles decorated SBA‒15 hybrid catalyst for selective oxidation of alcohols under ‘mild’ conditions

Herein, we develop an efficient and novel catalytic system, i.e. silver nanoparticles (AgNPs) incorporated mesoporous silica SBA‒15/copolymer hybrid material, for selective oxidation of different alcohols to aldehydes or ketones under ‘mild’ conditions. The copolymer of N,-N -dimethylaminoethyl methacrylate and 2-hydroxyethyl acrylate (p(DMAEMA- co -HEA)) was used to graft the surface-modified SBA‒15 (MS) using free radical polymerization method. Then AgNPs were decorated on the polymer grafted SBA‒15. The dual (thermal and pH) responsive behaviors of the AgNPs/p(DMAEMA- co -HEA)/MS catalyst were investigated using the dynamic light scattering technique. The lower critical solution temperature (LCST) of the copolymer was found to be approximately 30–35 °C. The catalytic activity of AgNPs/p(DMAEMA- co -HEA)/MS was investigated for the selective oxidation of different alcohols to aldehydes or ketones. The conversion of catalytic products and selectivity were calculated using gas chromatographic techniques, whereas the molecular structure of products was determined using 1 H and 13 C nuclear magnetic resonance spectroscopy. The catalyst showed improved catalytic activity toward the oxidation of alcohols to aldehydes in aqueous medium below LCST and pKa value (7–7.5) of the copolymer. The selectivity toward the corresponding aldehyde was found to be significantly high (99%). The main advantages of the hybrid catalyst as compared to existing catalysts include outstanding alcohol conversion (up to 99%), short reaction time (1 h), small necessary amount of catalyst (6 mg), and performing the catalytic conversion at room temperature using water as a solvent, which are highly beneficial for organic conversion under mild reaction conditions. • A catalytic system for selective oxidation of alcohols under ‘mild’ conditions was developed. • The catalyst consists of a temperature and pH-responsive copolymer, SBA-15, and Ag nanoparticles. • The catalyst showed outstanding alcohol conversion (up to 99%) within a short reaction time (1 h). • The catalyst performed the catalytic conversion at room temperature using water as a solvent.

Amine-functionalized metal–organic framework-based Pd nanoparticles: highly efficient multifunctional catalysts for base-free aerobic oxidation of different alcohols

Metal–organic framework-based palladium nanoparticles are found to be highly efficient multifunctional catalysts for the base-free aerobic oxidation of different aliphatic, aromatic and hetero-aromatic alcohols.

Synthesis and Structure of Copper Complexes of a N6O4 Macrocyclic Ligand and Catalytic Application in Alcohol Oxidation

Reactions between N6O4 macrocyclic 1,4,19,22,25,40-hexaaza-10,13,31,34-tetraoxa-6,14,27,35(1,4)-tetrabenzenacyclopentacontane (L) and several copper salts (viz. trifuoromethane and toluene sulfonates, nitrate, perchlorate, benzoate, and acetate) led to the formation of dinuclear compounds [Cu2(OSO2CF3)2(DMF)2L](SO3CF3)2 (1), [Cu2(p-OSO2C6H4Me)2L(DMF)2](SO3C6H4Me)2 (2), [Cu2(ONO2)2L(DMF)2](NO3)2 (3), [Cu2(OClO3)2(DMF)2L](ClO4)2 (4), [Cu2(OOCPh)2L(H2O)2](O2CPh)2 (5), and [Cu2(OOCMe)4L] (6), which were characterized by IR, elemental analysis and TG-DTA (thermogravimetric-differential thermal analysis), as well as by single-crystal X-ray diffraction, EPR (electron paramagnetic resonance) spectroscopy, and electrochemical techniques (cyclic voltammetry and controlled potential electrolysis). The molecular structures of compounds 1–6 reveal a considerable conformational flexibility of the ligand L, which allowed its readjustment for the formation of the metal compounds and confirmed the presence of dinuclear endo macrocyclic species. In every case, the L ligand coordinates to each copper cation via three nitrogen atoms, with the remaining coordination positions of the metal square pyramid environment being accomplished by neutral or anionic ligands. The macrocyclic cavities appear to be adequate for the enclosure of a neutral species as proved by compound 6 with 1,4-dioxane. The compounds, in combination with the TEMPO (2,2,6,6-tetramethyl-piperidinyloxyl) radical and in alkaline aqueous solution, act as efficient catalysts in the aerobic oxidation of different alcohols to the corresponding aldehydes (yields up to 99% and TON up 232) after 20 h at 70 °C. In addition, the microwave-assisted solvent-free peroxidative oxidation (by tert-butylhydroperoxide, TBHP) of 1-phenylethanol led to acetophenone yields up to 99% and TOF of 1.1 × 103 after 0.5 h, without any additive.

Cu(II) Schiff base complex supported on Fe3O4 nanoparticles as an efficient nanocatalyst for the selective aerobic oxidation of alcohols

Herein, we have prepared a new Cu(II) Schiff base complex supported onto the surface of modified Fe3O4 nanoparticles as highly stable, heterogeneous and magnetically recyclable nanocatalyst for the selective aerobic oxidation of different alcohols. The structure, morphology, chemical composition and magnetic property of the nanocatalyst and its precursors were characterized using FT‐IR, TGA, AAS, ICP‐AES, XRD, SEM, EDS, VSM and N2 adsorption–desorption analyses. Characterization results exhibited the uniform spherical morphology for nanocatalyst and its precursors. A promising eco‐friendly method with short reaction time and high conversion and selectivity for oxidation of various primary and secondary alcohols under O2 atmosphere condition was achieved. The synthesized nanocatalyst could be recovered easily by applying an external magnetic field and reused for least eight subsequent reaction cycles with only negligible deterioration in catalytic performance.

Linear amphiphilic TEMPO-grafted poly(ether sulfone) as polymeric interfacial catalyst: Synthesis, self-assembly behavior, and application

In this study, we report the development of a novel recyclable polymer-supported interfacial catalyst for Montanari oxidation. The catalyst was prepared by immobilization of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) on poly(ether sulfone) (PES) bridged by imidazole groups and characterized by 1H nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, elemental analysis, contact angle measurement, and transmission electron microscopy (TEM). This well-designed polymer was self-assembled into nanoaggregates in CH2Cl2. It was then used as Pickering emulsifier in Montanari oxidation system (NaClO/NaBr/immobilized TEMPO) for selective oxidation of different alcohols, which exhibited higher activity due to the enhanced mass transfer through microreactor mechanism. Moreover, this polymeric interfacial catalyst was pH-sensitive and could be easily recycled by adding small amount of acid, and subsequent cycles of alcohol oxidation showed no loss on either conversion or selectivity. This study represents an innovative approach for developing polymeric interfacial catalyst.

Catalytic polymeric membranes with palladium nanoparticle/multi-wall carbon nanotubes as hierarchical nanofillers: preparation, characterization and application

In this study, incorporation of Palladium nanoparticles into the membrane matrix using hierarchical nanostructures is reported as a novel approach to prepare catalytic polymeric membranes (CPMs). CMPs are prepared through a phase inversion method by loading of palladium nanoparticles decorated multi-wall carbon nanotubes (Pd–MWCNTs) with three different concentrations (0.1 %, 0.5 % and 1 wt%) in polysulfone/t-BA–EDA grafted polysulfone matrix. The Pd-MWCNTs impregnated PSf/PSf–g–P(t-BA–EDA) membranes are thoroughly characterized using TEM and XRD. SEM, TGA and DSC analyses were also performed to evaluate the effect of the Pd–MWCNTs on the morphology and thermal properties of catalytic membranes. The developed membranes are applied in a flow-through mode and showed excellent catalytic activities for selective oxidation of different alcohols to the corresponding aldehydes or ketones at solvent-free conditions. It was found that the reactivity and reusability of this catalytic membranes containing Pd–MWCNT were better than the conventional catalytic membranes containing free Pd nanoparticles. Catalytic membrane containing 1 % of Pd–MWCNT showed the highest reaction conversion (> 98 %) in 5th cycle for benzyl alcohol oxidation. Moreover, 100 % aldehyde and ketone selectivity were observed for all the catalytic membrane samples.

Green oxidation of alcohols with hydrogen peroxide catalyzed by a tetra-cobalt polyoxometalate in water

In this work it was demonstrated that the sodium and potassium salts of a sandwich-type tetra-cobalt tungstophosphate, [Co4(H2O)2(PW9O34)2]10−, are efficient catalysts for the selective oxidation of alcohols into corresponding aldehydes with hydrogen peroxide in water. Among these two salts, Na10[Co4(H2O)2(PW9O34)2]·27H2O complex showed better catalytic activity for the alcohols’ oxidation. Using trace amounts of catalyst, different benzylic and aliphatic hydroxyl groups were converted into the corresponding carbonyl compounds in high to excellent yields. In this work green and efficient catalytic oxidation of various alcohols to aldehydes and ketons with a sandwich-type tetra-cobalt tungstophosphate, [Co4(H2O)2(PW9O34)2]10−, is developed. High-to-excellent yields for oxidation of different alcohols by hydrogen peroxide in water are some advantageous of this catalytic system.

Improvement the Activity and Selectivity of Fenton System in the Oxidation of Alcohols

The reactivity and selectivity of Fenton system (Fe2+/H2O2) were improved with N-hydroxyphthalimide (NHPI) as cocatalyst. The oxidation process of benzyl alcohol to benzaldehyde has been studied. The reaction catalyzed by this new Fe2+/H2O2/NHPI system can be well performed under room temperature without adding any organic solvent. Besides, this catalyst system is effective for the oxidation of different alcohols.

An efficient oxidation of alcohols using a new trinuclear copper complex as a reusable catalyst under solvent free conditions

A new copper complex has shown efficacy as a catalyst for the selective oxidation of different alcohols using H2O2 as an oxidant under solvent free conditions.

Ionic liquids promoted the C H oxidation of alcohols to carbonyl compounds using a new polysiloxane-supported (salen)chromium(III) catalyst

Abstract An ion-exchangeable layered polysiloxane was first used as support for immobilizing a sulphonato-(salen)chromium(III) complex, and the resulted catalyst exhibited moderate to great reactivities in the C H oxidation of different alcohols into carbonyl compounds when aqueous hydrogen peroxide were employed as oxidant. And then three room temperature ionic liquids were loaded respectively for the purpose of recycling, and indeed the ionic liquid phases containing catalyst could be recycled effectively. At last, a novel layered structure of the supported catalyst was afforded and briefly discussed after X-ray powder diffraction analysis.

Oxidation of benzylic and some aliphatic alcohols 1,2-ethylenebis(triphenylphosphonium)chlorochromate (EBTPPCC): As a new, an efficient and mild oxidant

1,2-Ethylenebis(triphenylphosphonium)chlorochromate was quantitatively prepared and used for the oxidation of various benzylic and some aliphatic alcohols to their corresponding carbonyl compounds in water or acetonitrile and under microwave irradiation. This new oxidizing agent has advantages over similar oxidants in terms of the amount of used oxidant, short reaction time, simple work-up, and high yields. Furthermore, the oxidation of alcohols occurred under microwave irradiation many times and it produced the corresponding carbonyl compounds with high yields and short reaction times, when compared with the conventional method. Finally, the oxidation of different alcohols were accomplished in water under reflux condition with good yields as green chemistry.

Hidróxido de níquel suportado em carbono: um catalisador de baixo custo para a eletro-oxidação de alcoóis em meio alcalino

The present manuscript shows the synthesis of nickel hydroxide supported in carbon (Ni(OH)2/C) as a alternative material for catalytic alcohol oxidation in alkaline medium. The Ni(OH)2/C was synthesized in different percentage using a sonic bath. No current densities variation during successive cyclic voltammetry experiments was observed. The Ni(OH)2/C electrodes exhibit a potent and persistent electrocatalytic activity towards the oxidation of different alcohols. In addition, alcohols electooxidation occurs in less positive potential compared with noble metal catalyst.

Au–Pd/AC as catalysts for alcohol oxidation: Effect of reaction parameters on catalytic activity and selectivity

The oxidation of different alcohols with molecular oxygen in water has been investigated using a range of activated carbon-supported Au–Pd bimetallic catalysts. The effect of the Au–Pd ratio on the conversion and selectivity was observed and a synergistic effect is present in a large range of the Au–Pd ratio, being maximized for Au 80–Pd 20 composition instead of Au 90–Pd 10 shown in glycerol oxidation [A. Villa, C. Campione, L. Prati, Catal. Lett. 115 (2007) 133]. Moreover the enhancement of conversion observed by adding a base resulted greater for gold-rich catalysts rather than for palladium-rich ones. The effect of the alcohol concentration and the metal/substrate ratio in the presence or the absence of the base was also studied revealing substantial differences in terms of both activity and selectivity. At 1 M concentration under biphasic conditions benzyl alcohol has been selectively oxidized to benzaldehyde (S90 = 98%) even in the presence of NaOH with a TOF of 18,000 h −1 using Au 60–Pd 40/AC as the catalyst.

Investigation of the Moffatt−Swern Oxidation in a Continuous Flow Microreactor System

The Moffatt−Swern oxidation of different alcohols is performed in a continuous flow microreactor system. The microreactor process offers significant advantages over the batch process. First, because of the small reactor volume, accumulation of the labile trifluoroacetoxydimethylsulfonium salt (3) and alkoxydimethylsulfonium salt (5) is minimized. Second, because of the short residence times, which can be applied in the microreactor, the exothermic Pummerer rearrangement of the unstable intermediate 3 is limited. Because of this, the process can be operated at remarkably high temperatures in comparison with a batch reaction, viz. 0−20 °C instead of −70 °C. In the present study, a continuous flow microreactor system was optimized using reactors of different volumes allowing modulation of the residence times of labile intermediates. The efficiency of mixing was studied using different mixing devices. It has been shown that the continuous flow microreactor is an ideal tool for rapid optimization of reaction p...

FluoRuGel: a versatile catalyst for aerobic alcohol oxidation in supercritical carbon dioxide

FluoRuGel--a hybrid fluorinated silica glass doped with TPAP (tetra-n-propylammonium perruthenate)--is a versatile catalyst for the aerobic oxidation of different alcohols in dense phase CO(2) with marked stabilization and activity enhancement of perruthenate upon its confinement in the sol-gel fluorinated silica matrix. A brief competitive analysis shows large potential rewards.

Detection of NAD<SUP>+</SUP>-Dependent Alcohol Dehydrogenase Activities in YR-1 Strain of <I>Mucor circinelloides</I>, a Potential Bioremediator of Petroleum Contaminated Soils

Different soluble NAD+-dependent alcohol dehydrogenase (ADH) isozymes were detected in cell-free homogenates from aerobically grown mycelia of YR-1 strain of Mucor circinelloides isolated from petroleum- contaminated soil samples. Depending on the carbon source present in the growth media, multiple NAD+-dependent ADHs were detected when hexadecane or decane was used as the sole carbon source in the culture media. ADH activities from aerobically or anaerobically grown mycelium or yeast cells, respectively, were detected when growth medium with glucose added was the sole carbon source; the enzyme activity exhibited optimum pH for the oxidation of different alcohols (methanol, ethanol, and hexadecanol) similar to that of the corresponding aldehyde (approximately 7.0). Zymogram analysis conducted with partially purified fractions of extracts from aerobic mycelium or anaerobic yeast cells of the YR-1 strain grown in glucose as the sole carbon source indicated the presence of a single NAD+-dependent ADH enzyme in each case, and the activity level was higher in the yeast cells. ADH enzyme from mycelium grown in different carbon sources showed high activity using ethanol as substrate, although higher activity was displayed when the cells were grown in hexadecane as the sole carbon source. Zymogram analysis with these extracts showed that this particular strain of M. circinelloides has four different isozymes with ADH activity and, interestingly, one of them, ADH4, was identified also as phenanthrene-diol- dehydrogenase, an enzyme that possibly participates in the aromatic hydrocarbon biodegradation pathway.