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This review paper delves into the diverse ways in which carbonaceous resources, sourced from renewable and sustainable origins, can be used in catalytic processes. Renewable carbonaceous materials that come from biomass-derived and waste feedstocks are key to developing more sustainable processes by replacing traditional carbon-based materials. By examining the potential of these renewable carbonaceous materials, this review aims to shed light on their significance in fostering environmentally conscious and sustainable practices within the realm of catalysis. The more important applications identified are biofuel production, tar removal, chemical production, photocatalytic systems, microbial fuel cell electrodes, and oxidation applications. Regarding biofuel production, biochar-supported catalysts have proved to be able to achieve biodiesel production with yields exceeding 70%. Furthermore, hydrochars and activated carbons derived from diverse biomass sources have demonstrated significant tar removal efficiency. For instance, rice husk char exhibited an increased BET surface area from 2.2 m2/g to 141 m2/g after pyrolysis at 600 °C, showcasing its effectiveness in adsorbing phenol and light aromatic hydrocarbons. Concerning chemical production and the oxidation of alcohols, the influence of biochar quantity and pre-calcination temperature on catalytic performance has been proven, achieving selectivity toward benzaldehyde exceeding 70%. [ABSTRACT FROM AUTHOR]

The G SP ‡ sp for route III SB (N=O---H) sb is 5.76 kcal/mol, while the G SP ‡ sp for route IV SB (H---N=O) sb is 7.71 kcal/mol. On the Reaction Mechanism of the Selective C(sp3)-H Functionalization of N -Benzylpiperidines Mediated by TEMPO Oxoammonium Cation Keywords: selectivity; C-H oxidation; alkoxyamino lactams; oxoammonium salt of TEMPO; sodium chlorite EN selectivity C-H oxidation alkoxyamino lactams oxoammonium salt of TEMPO sodium chlorite 3662 3669 8 10/19/23 20231102 NES 231102 Graph It is now well-recognized that both 2,2,6,6-tetramethylpiperidine-1-oxoammonium cation (TEMPO SP + sp , B A b ) and its 4-amine-analogue cation 4-AcNH-TEMPO SP + sp are mild and selective oxidizing reagents of primary and secondary alcohols to their respective carbonyl compounds. On the other hand, comparing route I SB (N=O---H) sb and route III SB (N=O---H) sb , we note that despite the I exo i C-H bond being weaker than the I endo i C-H bond, [36] the latter hydrogen is slightly positive, [17] and a small but significant increase in the activation energy of 0.66 kcal/mol is observed. [Extracted from the article]

Bi-based perovskites (Bi 2 WO 6 , Bi 2 MoO 6 , BiFeO 3 , Bi 4 Ti 3 O 12 , etc.) have been documented as promising visible-light responsive materials for different photocatalytic applications (wastewater treatment, water splitting, CO 2 reduction, and oxidation of hydrocarbons and alcohols to produce valuable chemicals). However, the main disadvantage of pure perovskites is the rapid recombination of photoinduced charge carriers and, therefore, low activity. Among different methods developed, creating heterojunctions, especially Z-scheme and S-scheme, is considered as the most effective approach to improve the photocatalytic performances of materials due to increased light absorption, improved separation of electrons-hole pairs, combination of different favorable properties of each component of a hybrid, possibility to use a wide range of semiconductors to construct an ideal composite. This critical review reports progress over the last 5 years in creating Z-scheme and S-scheme composites based on Bi-containing perovskites in photocatalysis for environmental remediation, hydrogen evolution, reduction of CO 2 to CO and CH 4 , and production of industrially important organic chemicals by oxidation of hydrocarbons and alcohols. Moreover, challenges and opportunities are considered into developing new photocatalytic materials with their possible future commercialization. The critical review suggests strategies to improve the photocatalytic activity and stability of Z-scheme and S-scheme heterojunctions. [Display omitted] • Recent progress in application of Bi-based perovskite photocatalysts is overviewed. • Creating Z/S-scheme heterojunctions is effective approach for improving activity. • Bi-based perovskite heterojunctions are promising for environmental applications. • Industrial-scale prospects for Bi-based Z/S-scheme heterojunctions are explored. [ABSTRACT FROM AUTHOR]

Selective oxidation of low-molecular-weight aliphatic alcohols like methanol and ethanol into carboxylates in acid/base hybrid electrolytic cells offers reduced process operating costs for the generation of fuels and value-added chemicals, which is environmentally and economically more desirable than their full oxidation to CO2. Herein, we report the in-situ fabrication of oxygen-vacancies-rich CuO nanosheets on a copper foam (CF) via a simple ultrasonication-assisted acid-etching method. The CuO/CF monolith electrode enables efficient and selective electrooxidation of ethanol and methanol into value-added acetate and formate with ~100% selectivity. First principles calculations reveal that oxygen vacancies in CuO nanosheets efficiently regulate the surface chemistry and electronic structure, provide abundant active sites, and enhance charge transfer that facilitates the adsorption of reactant molecules on the catalyst surface. The as-prepared CuO/CF monolith electrode shows excellent stability for alcohol oxidation at current densities >200 mA·cm2 for 24 h. Moreover, the abundant oxygen vacancies significantly enhance the intrinsic indicators of the catalyst in terms of specific activity and outstanding turnover frequencies of 5.8k s−1 and 6k s−1 for acetate and formate normalized by their respective faradaic efficiencies at an applied potential of 1.82 V vs. RHE. Converting low-molecular-weight aliphatic alcohols like methanol and ethanol into value-added chemicals such as carboxylates in electrolytic cells offers low operating costs, but non-noble-metal catalysts often bring about low selectivities and overoxidation to CO2. Here, the authors report the efficient and selective electrooxidation of ethanol and methanol into acetate and formate on in-situ generated oxygen-vacancies-rich CuO nanosheets on a copper foam via ultrasonication-assisted acid-etching. [ABSTRACT FROM AUTHOR]

Background: Propionic acid as a very valuable chemical is in high demand, and it is industrially produced via the oxo-synthesis of ethylene or ethyl alcohol and via the oxidation of propionaldehyde with oxygen. It is urgent to discover a new preparation method for propionic acid via a green route. Recyclable amino-acid-based organic–inorganic heteropolyoxometalates were first used to high-efficiently catalyse the selective oxidation of 1-propanol to propionic acid with H2O2 as an oxidant. Result: A series of amino-acid-based heteropoly catalysts using different types of amino acids and heteropoly acids were synthesized, and the experimental results showed proline-based heteropolyphosphatotungstate (ProH)3[PW12O40] exhibited excellent catalytic activity for the selective catalytic oxidation of 1-propanol to propionic acid owing to its high capacity as an oxygen transfer agent and suitable acidity. Under optimized reaction conditions, the conversion of 1-propanol and the selectivity of propionic acid reached 88% and 75%, respectively. Over four cycles, the conversion remained at >80%, and the selectivity was >60%. (ProH)3[PW12O40] was also used to catalyse the oxidations of 1-butanol, 1-pentanol, 1-hexanol, and benzyl alcohol. All the reactions had high conversions, with the corresponding acids being the primary oxidation product. Conclusions: Proline-based heteropolyoxometalate (ProH)3[PW12O40] has been successfully used to catalyse the selective oxidation of primary alcohols to the corresponding carboxylic acids with H2O2 as the oxidant. The new developed catalytic oxidation system is mild, high-efficient, and reliable. This study provides a potential green route for the preparation propionic acid. [ABSTRACT FROM AUTHOR]

Heterogeneous catalysts are more prominent rather than homogenous catalysts since they are simply separated from products. To improve and develop heterogeneous catalysts, two core–shell magnetic nanocatalysts are prepared by anchoring of Cu and Ce complexes on the surface of Fe3O4, then the efficiency of the obtained catalysts are tested toward both chemical and electrochemical oxidation of sulfide and alcohol derivatives. Characterization of mentioned catalysts was performed by using FT-IR, XRD, EDX and SEM. The obtained results confirm that the reported method has outstanding advantages such as short reaction time, high yield, easy operation, easy separation, inexpensive and non-toxic material and chemical and thermal stability. [ABSTRACT FROM AUTHOR]

Chromium(III)‐doped layered double hydroxide supported copper nanoparticles (Cr3+‐Cu0/LDH) has been prepared as an efficient and reusable catalyst using simple and versatile synthetic method. Effect of doping of Cr3+ to the layered double hydroxide supported Cu0 nanoparticles was evaluated for the oxidation of alcohols and hydrocarbons by varying the amount of Cr3+ loading in the catalyst. The catalyst with Cu:Cr ratio= 1:1 afforded highest catalytic activity among the synthesized catalysts towards the oxidation using TBHP (tBuOOH) in aqueous medium and was structurally characterized by Fourier Transform Infrared Spectroscopy (FTIR), X‐Ray Diffraction Spectroscopy (XRD), Field Emission Gun‐Scanning Electron Microscopy (FEG‐SEM), Energy‐dispersive X‐Ray Spectroscopy (EDX), High Resolution‐Transmission Electron Spectroscopy (HR‐TEM), Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP‐AES) and X‐Ray Photoelectron Spectroscopy (XPS). The high activity and selectivity was assigned to the synergistic electronic interaction between copper(0) nanoparticles and chromium(III) ions based on experimental data and XPS results. Moreover, the high stability of Cu0 and Cr3+ in the catalyst was attributed to the strong metal‐support interactions, which make the catalyst recyclable upto five runs. [ABSTRACT FROM AUTHOR]

Different synthetic routes have been developed to obtain the aqua complex trans‐[RuII(trpy)(pypz‐H)(OH2)](PF6)2, Ru6. This complex, together with the chlorido intermediate complexes cis‐ and trans‐[RuIICl(pypz‐H)(trpy)]+, Ru5a and Ru5b, have been fully characterized by analytical, spectroscopic, and electrochemical methods. Furthermore, the trans‐Ru5b complex has been characterized in the solid state through single‐crystal X‐ray diffraction analysis. The aqua complex Ru6 was tested as catalyst in the photooxidation of alcohols in water and in the chemical oxidation of alkenes, displaying a good performance with high selectivity values in both catalytic processes. [ABSTRACT FROM AUTHOR]

The oxidation of alcohols to aldehydes, ketones, and carboxylic acids is reported using 2,2,6,6‐tetramethylpiperidine‐4‐acetamido‐hydroxyammonium tetrafluoroborate as a catalyst in conjunction with sodium hypochlorite pentahydrate as a terminal oxidant. The reaction is generally complete within 30–120 min using an acetonitrile/water mix as the solvent, and no additives are required. Product yields are good to excellent and of particular note is that the methodology can be used to access aryl α‐trifluoromethyl ketones. A hydroxyammonium cation can be used as a catalyst for the fast and easy oxidation of alcohols to aldehydes, ketones, and carboxylic acids. [ABSTRACT FROM AUTHOR]

Highlights • Trimetallic Pt-Ag-Ni NPs have been successfully fabricated. • The Pt-Ag-Ni NPs can serve as a new class of advanced nanocatalysts. • SPR induce PtAgNi NPs display great enhancement in catalytic activity. • This work offers a feasible route for engineering desirable nanocatalysts. Abstract High-efficiency adsorption of solar energy is a lofty goal and the pursuit of efficient photocatalyst is also one of the tough challenges. It's a growing interesting in the technology that is on the basis of surface plasma resonance (SPR) plasma resonance of the alloy nanoparticles (NPs). We herein successfully design a facile class of trimetallic Pt-Ag-Ni alloy NPs that combined the advantages of electronic effect, size and synergistic effect. Impressively, the Pt 2 Ag 1 Ni 1 NPs possess excellent electrocatalytic under visible light ethylene glycol oxidation reaction (EGOR) and glycerol oxidation reaction (GOR) with the mass activity founded to be: 7.99 and 4.88 A/mg, respectively. More significantly, SPR effect induces the optimal Pt-Ag-Ni NPs mass activity enhancement at 1.83 and 1.78 times higher under visible light than under environmental conditions. The design and SPR investigation of the trimetallic Pt-Ag-Ni alloy NPs in the research may provide a new approach for further development of high-performance nanocatalysts. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

A new kind of bionanohybrids, synthesized by using 63 kDa‐lipase from Candida rugosa (CRL) in the presence of polyethyleneimine (PEI) by in situ formation of Pd (0) nanoparticles (PdNPs) in aqueous media at room temperature were obtained. Addition of Triton X‐100 as additive was also used. XRD confirmed the formation of crystalline Pd (0) as metal species. TEM analyses revealed PdNPs ranging from 6 to 8 nm, whereas using Triton X‐100 the size range of the nanoparticles was 9 to 24 nm (mainly being 13 nm). PdNPs of biohybrid created only with Triton X‐100 ranged from 8 to 21 nm. The different heterogeneous nanobiohybrids were applied as catalyst in the oxidation of benzyl alcohol under mild conditions. In all cases, they were selective to the synthesis of alcohol to benzaldehyde without traces of carboxylic acid. More than >99 % conversion was obtained in THF at 50 °C under air as oxidant. The addition of hydrogen peroxide improved the conversion initially but the reaction was stopped at around 50–68 % conversion after 24 h in the best of cases. These new nanocatalysts synthesized using PEI showed a very high recyclability, maintaining >95 % activity after 5 cycles of use. Also successful results were obtained in the oxidation of other aromatic primary and secondary alcohols. The new PEI‐nanobiohybrids conserved the enzymatic activity and showed excellent results in metallic‐enzymatic domino reaction. Bionanocatalyst for selective oxidation: Bionanohybrids of lipase‐PEI−Pd nanoparticles were used as the first time for selective oxidation of aromatic alcohols at moderate conditions. Higher conversion and excellent >99 % selectivity in the Pd‐catalyzed oxidation of several aromatic alcohols to the corresponding aldehydes were obtained. Also cascade process was successfully obtained demonstrating the applicability of metallic and enzymatic activities of these nanocatalysts. [ABSTRACT FROM AUTHOR]

Herein, a well-defined nanostructure with leaf-like WO3 nanoflakes decorated on g-C3N4 was constructed via a facile impregnation and subsequent annealing method. The prepared WO3/g-C3N4 exhibited excellent catalytic activity for the selective oxidation of alcohols under mild conditions, and satisfactory yields to the corresponding carbonyl compounds were achieved without using non-green additives and organic solvents. It was found that the enhanced catalytic activity could be attributed to the enlarged specific surface area, the well-defined nanostructure, and the strong interactions between WO3 and g-C3N4. The distribution of WO3 nanoflakes on the g-C3N4 support increased the number of catalytically active sites for this reaction. XPS analysis suggested that a synergistic electron effect occurred because of the electron transfer from g-C3N4 to WO3. Moreover, the effects of reaction temperature, reaction time, oxidant amount and catalyst dosage on catalytic activity were investigated. Recycle studies showed that the catalyst could be readily recovered and no obvious decrease in catalytic efficiency was observed after seven cycles. The present catalytic system can afford a wide substrate scope for both aryl and alkyl alcohols with superior conversion and selectivity. Also, a plausible reaction mechanism was proposed to better illustrate the catalytic process. This work might provide a facile construction of a well-defined WO3/g-C3N4 catalyst for the selective oxidation of alcohols using a sustainable approach. [ABSTRACT FROM AUTHOR]

Several new trinuclear ruthenium carbonyl complexes chelated with 6-bromopyridine alcohol ligands, [6-bromopyC(CH2)4O]Ru3(CO)9 (1a), [6-bromopyC(CH2)5O]Ru3(CO)9 (1b), [6-bromopyC(Me)2O]Ru3(CO)9 (1c) and [6-bromopyCMeC6H5O]Ru3(CO)9 (1d), were synthesized by the reaction of Ru3(CO)12 with 6-bromopyC(CH2)4OH (L1H), 6-bromopyC(CH2)5OH (L2H), 6-bromopyC(Me)2OH (L3H) and 6-bromopyCMeC6H5OH (L4H) in refluxing THF, respectively. The free ligands L1H–L4H were synthesized by the nucleophilic reaction of lithium salt (generated from 2,6-dibromopyridine and n-BuLi) with the corresponding ketones. Furthermore, these pyridine-based ligands were characterized by NMR spectroscopy and elemental analyses. All the four ruthenium carbonyl complexes were well characterized by NMR, IR, single-crystal X-ray crystallography, etc. Complexes 1a–1d were found to exhibit high catalytic activities for the dehydrogenative oxidation of secondary alcohols to give their corresponding products in good to excellent yields. [ABSTRACT FROM AUTHOR]

Abstract: Covalent triazine frameworks (CTFs) with aromatic triazine linkages have recently received increasing interest for various applications because of their rich nitrogen content and high chemical stability. Owing to the strong aromatic C=N bond and high chemical stability, only a few CTFs are crystalline, and most CTFs are amorphous. Herein we report a new general strategy to give highly crystalline CTFs by in situ formation of aldehyde monomers through the controlled oxidation of alcohols. This general strategy allows a series of crystalline CTFs with different monomers to be prepared, which are shown to have higher thermal stability and enhanced performance in photocatalysis as compared with the less crystalline or amorphous CTFs. This open‐system approach is very simple and convenient, which presents a potential pathway to large‐scale industrial production of crystalline CTFs. [ABSTRACT FROM AUTHOR]

Abstract: Homogeneous Cu(I)/NMI/TEMPO catalyst system (TEMPO = 2,2,6,6-tetramethylpiperidine-N-oxyl) has been investigated for its catalysis on the aerobic oxidation of 1-octanol and other alcohols into aldehydes under room temperature. The catalytic species was found to be a Cu(I) centre coordinated by two NMI molecules and other two weakly bound solvent molecules, [Cu(NMI)2(Sol)2]+ (Sol = solvent). When CuI was used, this species could be [Cu(NMI)I(Sol)2]. Not like being speculated previously, NMI in this system acts solely as a ligand and its role coordinated to the copper centre enhanced the electron density on the metal centre which promoted the O2 binding in the catalysis. The labile solvent binding to the Cu(I) centre is essential to ensure both oxygen and substrate binding. The catalyst system is suitable for the oxidation of various alcohols using a simple reaction setup and workup. In particular, the system possesses strong oxidizing capability in quantitative conversion of benzylic alcohols regardless of the substituents on the phenyl ring and allylic alcohols into aldehydes. A plausible mechanism was also proposed for the catalysis.Graphical Abstract: The aerobic oxidation of primary alcohols at room temperature to corresponding aldehydes was achieved by the catalyst composed by Cu(I) and methyl imidazole (NMI) mediated by TEMPO in acetonitrile. The catalytic species is proposed to be such a Cu(I) complex that two of its four coordinating sites are occupied by a strong ligand(s) and the rest two are weakly bound by solvent molecules. [ABSTRACT FROM AUTHOR]

We describe an eco-friendly, practical and operationally simple procedure for the bis(methoxypropyl) ether-promoted oxidation of aromatic alcohols into aromatic carboxylic acids and aromatic ketones with atmospheric dioxygen as the sole oxidant. This chemical process is clean with high conversion and good selectivity, and an external initiator, catalyst, additive and base are not required. The virtue of this reaction is highlighted by its easily available and economical raw materials and excellent functional group tolerance (acid-, base- and oxidant-labile groups). [ABSTRACT FROM AUTHOR]

Trifluoromethyl ketones have recently been attracting considerable attention because they represent powerful synthetic building blocks with potential pharmaceutical applications. This short review provides an overview of recent development in the synthesis of aryl trifluoromethyl ketones with novel reagents. 1 Introduction 2 Various Methods for the Synthesis of Aryl Trifluoromethyl Ketones 2.1 Oxidation of Trifluoromethyl Alcohols 2.2 Nucleophilic Trifluoromethylation Reactions 2.3 Electrophilic-Type Reactions 2.4 Recently Developed Direct Trifluoroacetylation 3 Conclusions [ABSTRACT FROM AUTHOR]

B(C6F5)3-catalyzed deoxygenation of ether-substituted alcohols and carbonyl compounds has been developed using (HMe2SiCH2)2 as the reductant. This unique reagent shows distinct superiority over traditional one silicon-centered hydrosilanes, giving the corresponding alkanes in high yields with good tolerance of ethers, aryl halides and alkenes. The control experiments suggest that (HMe2SiCH2)2 might facilitate the approach in an intramolecular Si/O activation manner. [ABSTRACT FROM AUTHOR]

Rare earths (RE) have been studied in the literature as additives in Pt and PtSn catalysts for the ethanol oxidation reaction (EOR), but their stability and influence on the mechanism of the EOR have not been reported. In this work, PtSnRE/C (RE: La, Ce, and Pr) catalysts were obtained by the polyol method, characterized, and their stability toward the EOR evaluated by cycling at two different potential ranges. The accelerated aging tests indicated that despite the changes in the CO stripping profiles, the ternary catalysts exhibit higher current densities after aging than Pt/C and PtSn/C catalysts. Even after dissolution of the rare-earth metals, as observed by energy-dispersive X-ray spectroscopy (EDS) before and after aging, the EOR activity after short-term stability tests was found to be higher than the initial one. The addition of these metals facilitates the retention of tin in the material, contributing to the overall stability of the bimetallic catalyst. The oxidation products of the ternary catalysts were evaluated by in situ Fourier transform infrared spectroscopy (FTIR) spectroscopy and high-performance liquid chromatography (HPLC), where the major products were found to be acetaldehyde and acetic acid, with only small concentrations of CO2. The improvement in the ethanol oxidation efficiency by PtSnRE/C catalysts can be explained by a bifunctional mechanism in which the rare-earth oxides are able to provide oxygenated species at low potentials. [ABSTRACT FROM AUTHOR]

Abstract: We aimed to immobilize a complex of iron(III) amine bis(phenolate) on silica‐coated magnetic nanoparticles as a new magnetically recoverable catalyst (Fe3O4@SiO2‐APTES‐FeLGDC). Both the chemical nature and the structure of catalyst were confirmed by using field‐emission transmission electron microscopy, field‐emission scanning electron microscopy, FTIR spectroscopy, thermogravimetric analysis, vibrating sample magnetometry, X‐ray photoelectron spectroscopy, XRD, atomic absorption spectroscopy, and elemental analysis. This sustainable catalyst leads to the efficient oxidation of a wide range of alcohols and sulfides with excellent conversion and selectivity under a mild conditions to their corresponding oxidized products, acids (or ketones) and sulfoxides, respectively. Furthermore, the stability of the structure and morphology of our efficient recyclable system was investigated, and all of the data proved that the complex was anchored firmly to the magnetite nanoparticles. [ABSTRACT FROM AUTHOR]

Abstract: The sustainable chemical industry encompasses a shift from the use of fossil carbon to renewable carbon. The synthesis of chemicals from nonedible biomass (cellulosic or oil) represents one of the key steps for “greening” the chemical industry. In this paper, we report the aerobic oxidative cleavage of C6 polyols (5‐HMF, glucose, fructose and sucrose) to oxalic acid (OA) and succinic acid (SA) in water under mild conditions using M@CNT and M@NCNT (M=Fe, V; CNT=carbon nanotubes; NCNT=N‐doped CNT), which, under suitable conditions, were recoverable and reusable without any loss of efficiency. The influence of the temperature, O2 pressure (P O 2 ), reaction time and stirring rate are discussed and the best reaction conditions are determined for an almost complete conversion of the starting material and a good OA yield of 48 %. SA and formic acid were the only co‐products. The former could be further converted into OA by oxidation in the presence of formic acid, resulting in an overall OA yield of >62 %. This process was clean and did not produce organic waste nor gas emissions. [ABSTRACT FROM AUTHOR]

Ammonium tungstate was found to be a facile and efficient catalyst for selective oxidation of alcohols to the corresponding carbonyl compounds with hydrogen peroxide as oxidant. Heterogeneous graphene oxide as acid effectively intensified the transformations and resulted in excellent yields. The use of water as solvent rendered the reactions promising both economically and environmentally. [ABSTRACT FROM AUTHOR]

The ferrate(vi) ion, [FeO4]2−, has attracted much interest in recent years because of its potential use as a green oxidant in organic synthesis and water treatment. Although there have been several reports on the use of ferrate(vi) for the oxidation of alcohols to the corresponding carbonyl compounds, the mechanism remains unclear. In this work, the kinetics of the oxidation of a series of alcohols with α-C–H bond dissociation energies ranging from 81 to 95 kcal mol−1 have been studied by UV/Vis spectrophotometry. The reactions are first-order in both [FeO4]2− and [alcohol]. The deuterium isotope effects for the oxidation of methanol/d4-methanol, ethanol/d6-ethanol and benzyl alcohol/d7-benzyl alcohol are 18.0 ± 0.1, 4.1 ± 0.1 and 11.2 ± 0.1, respectively. A linear correlation is found between the second-order rate constants and the α-C–H bond dissociation energies (BDEs) of the alcohols, consistent with a hydrogen atom transfer (HAT) mechanism. The proposed HAT mechanism is supported by DFT calculations. [ABSTRACT FROM AUTHOR]

A metal-free iodine/NaOH-catalyzed oxidation of alcohols and aldehydes has been developed for the practical synthesis of a wide range of carboxylic acids using water as the solvent. This transformation involves dehydrogenation of an alcohol, followed by a fast attack of water on an aldehyde. This method is mostly free from chromatographic purification, which makes it suitable for large-scale synthesis. The iodine species formed during the reaction as the active oxidation catalyst has been deduced as IO2− by control experiments. We also demonstrate a 10 gram scale synthesis of furandicarboxylic acid (FDCA) from HMF in good yield using our method. [ABSTRACT FROM AUTHOR]

A copper(II) complex containing tetradentate NO Schiff base ligand immobilized into aminopropyl-functionalised MCM-41 (mobile crystalline material number 41), was prepared and characterized by Fourier-transform infrared, X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, N adsorption-desorption and inductively coupled plasma analysis techniques. The novel heterogeneous catalyst, MCM-41-pr-NH-CuL, can be successfully applied for efficient and selective oxidation of different primary and secondary alcohols to the corresponding carbonyl compounds using hydrogen peroxide as an oxidant in acetonitrile at 60 °C. The effect of reaction parameters such as solvent, amount of catalyst, temperature and kind of oxidant on the oxidation of benzyl alcohol was also studied. The prepared catalyst could be recovered and reused four times without important loss of its catalytic performance. The heterogeneous MCM-41-pr-NH-CuL catalyst was found to be catalytically more active in the oxidation of alcohols compared to the similar type of copper(II) Schiff base complex in homogeneous media under the same reaction conditions. [ABSTRACT FROM AUTHOR]

A novel catalyst of gold nanoparticles supported on cellulose fibres with the ionic liquid framework (Au NPs@CL-IL) has been shown to be a highly active and recyclable catalyst for the oxidation of primary and secondary alcohols and reduction of nitroarenes in aqueous media. The reusability of this catalyst is high, and it can be reused ten times without a significant decrease in its catalytic activity. Furthermore, transmission electron micrographs of the recovered catalyst show the presence of well-distributed Au NPs on the CL-IL fibres without any aggregation. [ABSTRACT FROM AUTHOR]

It is demonstrated here that tridentate imine ligands can control the nuclearity of copper(II) complexes based on the donor atoms present in the ligand. The N,N',N''-donating imine ligand led to a mononuclear compound, namely dichlorido[N,N-dimethyl-N'-(pyridin-2-ylmethylidene)ethane-1,2-di-amine]copper(II) monohydrate, [CuCl2(C10H15N3)]⋅H2O, 1, while the N,N',O-donating imine ligand produced a binuclear metal complex, namely μ2-chlorido-dichlorido(μ2-2-{[2-(dimethylamino)ethyl]iminomethyl}phenolato)(N,N-dimethylethylenediamine)dicopper(II) 0.11-hydrate, [Cu2(C11H15N2O)Cl3(C4H12N2)]⋅0.11H2O, 2. The structure of 2 is a remarkable example of a binuclear copper(II) complex containing a single substituted 2-iminomethylphenolate ligand that has two copper(II) sites in square-pyramidal coordination. [ABSTRACT FROM AUTHOR]

BACKGROUND Unlike Pt and Au, Ag has recently been reported to be an active catalyst for the synthesis of glycolic acid from the liquid phase oxidation of glycerol ( GLY). In order to provide comparative information about the kinetics of this reaction using Pt, Au or Ag, a kinetic model was derived for each catalyst (Ag/, Pt/ and Au/ Al2O3), using the experimental results obtained at different temperatures. RESULTS A power-law kinetic model was proposed for each catalyst, which included the Khang-Levenspiel model to evaluate potential catalyst deactivation. All three kinetic models predicted well the experimental concentrations. Pt/ and Au/ Al2O3 showed higher kinetic rate constants, the highest being that of the production of glyceric acid. The lower the metal particle size, the higher the kinetic rate constant of the production of glyceric acid was. Deactivation parameters played an important role in the model of Pt/ Al2O3, so that Au/ and Ag/ Al2O3 seemed to be more resistant to deactivation. CONCLUSIONS This work reports the first kinetic model for the oxidation of GLY using an Ag-based catalyst. It showed a noticeable kinetic rate constant for the production of glycolic acid. The activation energies obtained were in the range 48-97 kJ mol−1. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The uniform monodisperse skull-like structure with diameter of 300-400 nm, rugged surface, many holes and bumps have been successfully synthesized via a simple hydrothermal route. The cubic fluorite structure of the synthesized skull-like CeO nanostructures was confirmed by X-ray diffraction. Mixed oxidation states (Ce4+ and Ce3+) were detected in the samples, confirmed using X-ray photoelectron spectroscopy and Raman spectrum. It has been proven that oxygen vacancies and Ce3+ ions exist at the grain surface and at the grain boundaries. The appearance of emission peaks and the visible luminescence peaks can be attributed to the oxygen related defects. [ABSTRACT FROM AUTHOR]

The 2-azaadamantane-N-oxyl (AZADO)- and 9-azanoradamantane- N-oxyl (nor-AZADO)-catalyzed selective oxidation of primary alcohols to the corresponding aldehydes is described. The use of tertbutyl nitrite as the co-catalyst enables efficient aerobic oxidation in MeCN instead of previously reported AcOH; this is important for the selectivity of the reaction. The addition of a solution of saturated aqueous NaHCO3 after the completion of the reaction was effective to suppress the overoxidation of the product to the corresponding carboxylic acid during the workup. [ABSTRACT FROM AUTHOR]

Selective oxidation of alcohols to aldehydes plays an important role in perfumery, pharmaceuticals, and agrochemicals industry. Different from traditional catalysis or photocatalytic process, here we report an effective photoelectrochemical (PEC) approach for selective anaerobic oxidation of alcohols accompanied with H2 production by means of solar energy. By using TiO2 nanowires modified with graphitic carbon layer as photoanode, benzyl alcohol (BA) has been oxidized to benzaldehyde with high efficiency and selectivity (>99 %) in aqueous media at room temperature, superior to individual electrocatalytic or photocatalytic processes. Moreover, this PEC synthesis method can be effectively extended to the oxidation of several other aryl alcohols to their corresponding aldehydes under mild conditions. The electron spin resonance (ESR) results indicate the formation of intermediate active oxygen (O2.−) on the photoanode, which further reacts with alcohols to produce final aldehyde compounds. [ABSTRACT FROM AUTHOR]

This work reports the zirconia (ZrOx) nanoparticles doped MnCO3 catalysts prepared by facile and simple coprecipitation technique and the synthesis of zirconia-manganese carbonate [X% ZrOx–MnCO3] (where X% = 0–7%) catalyst which upon calcination at 400°C is converted to zirconia-manganese dioxide [1% ZrOx–MnO2] and when calcined at 500°C is converted to zirconia-manganic trioxide [1% ZrOx–Mn2O3]. A comparative catalytic study was performed to investigate the catalytic efficiency between carbonate and oxides for the selective oxidation of 1-phenylethanol by using molecular O2 as a clean oxidant. The influence of several parameters such as w/w% of ZrOx, reaction time, calcination temperature, catalyst amount, and reaction temperature has been thoroughly examined using oxidation of 1-phenylethanol as a model substrate. The 1% ZrOx–MnCO3 precalcined at 300°C exhibited the best catalytic efficiency. It was found that ZrOx nanoparticles also play an essential role in enhancing the effectiveness of the catalytic system for the aerobic oxidation of alcohols. Furthermore, the physical and chemical properties of synthesized catalysts were evaluated by microscopic and spectroscopic techniques. An extremely high specific activity of 40 mmol·g−1·h−1 with a 100% conversion of oxidation product and selectivity of >99% was achieved within extremely short reaction time (6 min). [ABSTRACT FROM AUTHOR]

In the hunt for a simple, mild, and scalable protocol for gold nanoparticle-catalyzed oxidation of benzylic and allylic alcohols under O2, we have used commercially available gold nanoparticles supported on alumina to selectively oxidize a large range of activated alcohols to the corresponding carbonyl compounds in good yields (68-99 %) and with excellent selectivity (ca. 100 %). The true heterogeneous nature of the catalysis by gold was demonstrated, allowing us to further adapt this protocol to continuous-flow reactors by using the tube-in-tube technology, in which higher yields were obtained thanks to an improved oxygenation of the reaction medium. [ABSTRACT FROM AUTHOR]

Carbon-nanodot-doped g-C3N4 is used as a photocatalyst to promote the aerobic oxidation of alcohols and oxyfunctionalisation of activated hydrocarbons. A critical E-factor analysis of the current reaction system reveals its limitations en route to environmentally acceptable oxidation procedures. [ABSTRACT FROM AUTHOR]

Oxidation is one of the most important industrial reactions as it yields useful products. Literature survey indicates the use of several organic oxidants for the oxidation of alcohols to the corresponding carbonyl compounds but inorganic oxidants have rarely been used. Further, the kinetic and thermodynamic aspects of oxidation of perfumery alcohols have not been investigated. In this paper, we report the kinetic studies of oxidation of acyclic primary perfumery alcohols, Nerol, Citronellol and Geraniol, to aldehydes using K2S2O8 and KIO4 in acidic medium. The oxidation was carried out under first order kinetic conditions with respect to the inorganic oxidants. The progress of reaction was monitored by iodometric estimation of the unreacted oxidants at regular time interval during the course of the reaction. The reaction was found to be independent of ionic strength (μ).The thermodynamic activation parameters have been determined from the variation of oxidation rate with temperature. Suitable reactionmechanism have been suggested for the oxidation of perfumery alcohols. [ABSTRACT FROM AUTHOR]

CuI N-heterocycle thiolate clusters efficiently catalyze the acceptorless dehydrogenation of alcohols at 70 °C. A variety of secondary/primary benzylic, allylic, and aliphatic alcohols are dehydrogenated to the corresponding ketones and aldehydes in high yields of isolated product upon release of H2. This simple catalytic system is involved in the synthesis of imines through the one-pot reaction of alcohols and amines. [ABSTRACT FROM AUTHOR]

Many important chemical transformations occur in two-phase reactions, which are widely used in chemical, pharmaceutical, and polymer manufacturing. We present an efficient method for performing two-phase reactions in microdroplets sheared by sheath gas without using a phase-transfer catalyst. This avoids disadvantages such as thermal instability, high cost, and, especially, the need to separate and recycle the catalysts. We show that various alcohols can be oxidized to the corresponding aldehydes and ketones within milliseconds in moderate to good yields (50-75 %). The scale-up of the present method was achieved at an isolated rate of 1.2 mg min−1 for the synthesis of 4-nitrobenzylaldehyde from 4-nitrobenzyl alcohol in the presence of sodium hypochlorite. The biphasic nature of this process, which avoids use of a phase-transfer catalyst, greatly enhances synthetic effectiveness. [ABSTRACT FROM AUTHOR]

One-pot electrochemical oxidation of alcohols to nitriles was carried out with ammonium acetate as the nitrogen source and 2,2,6,6-tetramethylpiperidinyl-l-oxy (TEMPO) as the catalyst. Cyclic voltammetry investigation showed that an obvious redox reaction between alcohol and TEMPO occurred efficiently in the presence of NH4OAc. The constant potential electrolysis of various functionalized alcohols, especially of benzylic alcohols, afforded the corresponding nitriles in moderate to excellent yields at ambient temperature. A plausible reaction mechanism of one-pot electrochemical oxidation of alcohols to nitriles was proposed based on the cyclic voltammetry investigation, in situ FTIR analysis and preparative electrolysis. [ABSTRACT FROM AUTHOR]

The selective and simultaneous production of hydrogen and chemicals from renewable alcohols was accomplished by using an electrolyzer, for which the anode electrocatalyst was an organometallic complex, [Rh(OTf)(trop2NH){P(4-BuC6H4)3}] (trop2NH=bis(5 H-dibenzo[ a, d]cyclohepten-5-yl)amine; −OTf=CF3SO3−), deposited on amorphous carbon and appropriately designed to promote the partial and selective oxidation of alcohols. The electrolyzer converted alcohols into industrially relevant chemicals and high-purity hydrogen at high volume and with very low energy consumption. [ABSTRACT FROM AUTHOR]

Selective oxidation of alcohols to aldehydes/ketones has been achieved with the help of 3-mercaptopropionic acid (MPA)-capped CdSe quantum dot (MPA-CdSe QD) and visible light. Visible-light-prompted electron-transfer reaction initiates the oxidation. The thiyl radical generated from the thiolate anion adsorbed on a CdSe QD plays a key role by abstracting the hydrogen atom from the C−H bond of the alcohol (R1CH(OH)R2). The reaction shows high efficiency, good functional group tolerance, and high site-selectivity in polyhydroxy compounds. The generality and selectivity reported here offer a new opportunity for further applications of QDs in organic transformations. [ABSTRACT FROM AUTHOR]

A catalytic system for the aerobic oxidation of alcohols by N-hydroxyphthalimide (NHPI) combined with cobalt porphyrin intercalated heterogeneous hybrid catalyst (CoTPP-Zn Al-LDH) has been developed. The results showed that this catalytic system can effectively catalyze the oxidation of alcohols to the corresponding carbonyl compounds. And the hybrid catalyst can be reused for five times with no appreciable reduction of activity. [ABSTRACT FROM AUTHOR]

A novel third-generation metalloporphyrin, chloro-5,10,15,20-tetrakis-(3′-bromine-4′-methoxyphenyl)-2,3,7,8,12,13,17,18-octabromoporphyrinatomanganese(iii), [MnIIIBr12T4(-OMe)PPCl], designated as MnBr12Por, was synthesized and characterized. The catalytic activity of the new manganese porphyrin was investigated in the oxidation of cyclohexane, adamantane and n-hexane by iodosylbenzene (PhIO) or iodobenzene diacetate (PhI(OAc)2) in comparison to the catalytic activity of the second-generation catalyst [MnIIIT4(-OMe)PPCl], designated as MnPor. All yields were based on oxidants. The MnBr12Por/PhIO system led to higher yields of cyclohexane oxidation products (45%) with high selectivity for cyclohexanol (80%) as compared to the MnPor/PhIO system (23% and 77%, respectively). Addition of imidazole to MnPor/PhIO increased the total product yield from 23 to 43%; addition of imidazole to MnBr12Por/PhIO did not alter the total product yield at all. For the MnPor/PhI(OAc)2 and MnBr12Por/PhI(OAc)2 systems, addition of imidazole increased the product yields from 19 to 45% and from 35 to 66%, respectively. Addition of water increased the total product yields during cyclohexane and adamantane oxidation for all the studied systems. In all cases, MnBr12Por performed better than MnPor. [ABSTRACT FROM AUTHOR]

Identifying the mechanism of a catalytic reaction is paramount for designing new and improved catalysts. Several alternative catalytic cycles for the copper/2,2,6,6-tetramethylpiperidine- N-oxyl (TEMPO)-catalyzed aerobic oxidation of alcohols to the corresponding aldehydes or ketones were examined using DFT at the SMD(CH3CN)-RIJCOSX-DSD-PBEB95/def2-TZVP//DF-PBED3BJ/def2-SVP level of theory. A catalytic cycle in which TEMPO remains coordinated to copper throughout was identified as the most likely mechanism. There are three components to the catalytic cycle: 1) hydrogen transfer from the alkoxyl ligand to coordinated TEMPO, 2) oxygen activation with formation of a peroxo complex, and 3) alcohol activation with transfer of the OH proton to the peroxo ligand. The oxidation takes place via a six-membered intramolecular hydrogen-transfer transition state. Importantly, this is not the rate-determining step, which instead involves oxygen activation and/or the initial alcohol activation. [ABSTRACT FROM AUTHOR]

Benzyl alcohols were oxidized with oxygen to aldehydes in excellent yields with high selectivities at room temperature. Dual catalysis was operative with HNO3 as the oxidant and precursor of the nitrogen oxides and with the use of 1,1,1,3,3,3-hexafluoro-2-propanol as a template catalyst and solvent. Fluorinated alcohols also increased the selectivity by inhibiting further oxidation to benzoic acids. Activation of nitric acid catalyzed aerobic oxidation by the fluorinated solvent made the use of 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) or a metal catalyst superfluous. [ABSTRACT FROM AUTHOR]

Oxoperoxo tungsten(VI) complex immobilized on Schiff base-modified Fe3O4super paramagnetic nanoparticles were synthesized and appropriately characterized using FT-IR, XRD, SEM, TEM, EDX, BET, and VSM analysis. The synthesized nanoparticles efficiently catalyzed oxidation of benzylic alcohols with H2O2as oxidant in high yields, with high to excellent selectivity. The catalyst can be recovered using an external magnetic field and recycled for subsequent oxidation reactions without any appreciable loss of efficiency. The simple preparation, high activity, excellent selectivity, and simple recoverability of the catalyst are advantageous. [ABSTRACT FROM AUTHOR]

A simple and convenient method for the construction of substituted cycloheptenones from 1-bromoocta-1,7-diene-3-ols has been developed. The reaction involves Pd(0)-catalyzed intramolecular 7-exo-trig cyclization followed by Pd(ii)-catalyzed oxidation of cyclic alcohol. The course of the reaction pathway has been evaluated using DFT calculations. [ABSTRACT FROM AUTHOR]

(2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO) was immobilized on crosslinked polystyrene (CPS) microspheres by polymer reaction to obtain microspheres of the heterogeneous catalyst TEMPO/CPS. TEMPO/CPS microspheres in combination with different transition metal salts were used in the aerobic oxidation of 1-phenylethanol. This work focuses on the catalytic activities and mechanisms of various co-catalysts, and the different behavior of these co-catalysts is explained for the first time with the theory of redox potentials, so that some important principles for selecting better transition metal salts as co-catalysts of TEMPO are presented. The experimental results show that 1-phenylethanol can be oxidized to acetophenone as the sole product with a high conversion of 96 % under mild conditions (at 55 °C and with molecular oxygen at ordinary pressure) by using the combinational catalyst consisting of TEMPO/CPS microspheres and transition metal salts. [ABSTRACT FROM AUTHOR]

Immobilised molybdenum thiosemicarbazide Schiff base complex on the surface of magnetite nanoparticles (MoO2—thio-SCMNPs) was used as a heterogeneous nanocatalyst for the oxidation of various benzylic alcohols to their corresponding carbonyl compounds in DMF and acetonitrile by H2O2 at 60°C. The progress of reaction was monitored by TLC and the products was characterised by GC. This new oxidising system has advantages over similar oxidant systems in terms of the mild and green reaction conditions, selectivity, simple work-up, and high yield. [ABSTRACT FROM AUTHOR]

A novel microbial strain Microbacterium oxydans with high alcohol dehydrogenase (ADH) activity and enantioselectivity was isolated from soil, through an effective screening procedure in which rac-1-phenylethanol was supplied as the sole carbon and energy source. After series optimization of fermentation, the biosynthesis of the ADH in Microbacterium oxydans reached a maximum of 120 U/l at 30 h of cultivation and the activity retained for considerable time (5 days). In the gram preparative biooxidation of 50 mM rac-1-phenylethanol using resting cells of Microbacterium oxydans, (S)-(-)-1-phenylethanol (>99.5% enantiomeric excess (e.e.), 40.1% yield) and acetophenone (34.6% yield) were obtained, respectively. [ABSTRACT FROM AUTHOR]

Electrode designs based on sheet racks and blocks with multidiffuse groove spaces and enriched active sites and scales would promote the commercial applications of electroactive materials. A facile one-pot hydrothermal approach is reported to synthesize mesoscopic porous Co3O4 or hybrid graphene (GO)/Co3O4 sheet-on-sheet racks and blocks. Three basic types of sheet scalability racks can be built in vertical and nonstacked edge orientations, such as neat micro/nanogroove rooms, butterfly wing scales, and wall groves, leading to highly exposed surface converges and sites. In particular, the stacked GO/Co3O4 sheet-on-sheet blocks (GO/Co3O4 blocks) can be oriented in vertical tower buildings. The atomic structures of the developed Co3O4 catalysts are dominant along the highly dense {112/111} interfaces and single crystal {111} and {112} facets. The electrochemical performance of the mesoscopic porous Co3O4 catalyst toward methanol and ethanol electrooxidation is evaluated in alkaline conditions. The mesoscopic hybrid GO/Co3O4 racks reveal superior catalytic activity in terms of oxidation currents and onset potentials, indicating the effect of the synergetic role of active Co3+ sites along the densely exposed {112} facets, graphene counterparts, and hierarchically nonstacked sheet racks on the electroactive functionality. Results indicate that the mesoscopic GO/Co3O4 sheet catalyst is suitable for highly efficient electrochemical reactions. [ABSTRACT FROM AUTHOR]