Oxidation Of Alcohols Research Articles

Catalytic Enantioselective Hydrogen Atom Abstraction Enables the Asymmetric Oxidation of Meso Diols.

Desymmetrization of meso diols is an important strategy for the synthesis of chiral oxygen-containing building blocks. Oxidative desymmetrization is an important subclass, but existing methods are often constrained by the need for activated alcohol substrates. We disclose a conceptually distinct strategy toward oxidative diol desymmetrization that is enabled by catalytic enantioselective hydrogen atom abstraction. Following single electron oxidation of a cinchona alkaloid-derived catalyst, enantiodetermining hydrogen atom abstraction generates a desymmetrized ketyl radical intermediate which reacts with either DIAD or O2 before in situ elimination to form valuable hydroxyketone products. A range of cyclic and acyclic meso diols are competent, defining the absolute configuration of up to four stereocenters in a single operation. As well as providing rapid access to complex hydroxyketones, this work emphasizes the broad synthetic potential of harnessing hydrogen atom abstraction in an enantioselective manner.

Facet-dependent spatial separation of dual cocatalysts on MOF photocatalysts for H2O2 production coupling biomass oxidation with enhanced performance

Cooperative coupling of photocatalytic two-electron oxygen reduction reaction (2e-ORR) with oxidative organic synthesis holds great promise for sustainable production of valuable chemicals. To achieve high performance, the rational design of photocatalysts with effective electron-hole separation and redox capability is crucial. Herein, a MOF-based photocatalyst with crystal facet-dependent spatial separation of dual cocatalysts is constructed for photocatalytic 2e-ORR coupled with vanillyl alcohol oxidation reaction (VAOR). The facet-dependent growth of reductive Pd and oxidative CoOx cocatalysts respectively on the {100} and {001} facets of MIL-125-NH2 enables the directional migration of photogenerated carries, facilitating the charge separation for redox reactions. Additionally, the interaction between Pd and MIL-125-NH2 modulates the Pd sites into electron-sufficient state with upshifted d-band center, promoting the O2 activation and *OOH intermediate formation. The rationally designed composite photocatalyst delivers an excellent H2O2 yield of 74.8 mM g−1 h−1 and a high vanillic acid production rate of 80.9 mM h−1 g−1 with the conversion and selectivity of 96.8 % and 91.1 %, respectively.

Study the effect of zinc oxide nanoparticles on degradation, antibacterial, thermal and morphological properties of polyvinyl alcohol films

Abstract In this study, a film was prepared from polyvinyl alcohol (PVA) and zinc oxide (ZnO) nanoparticles (nano-ZnO) via the casting method. Nanoparticles were added to PVA biopolymer to create reinforced biocomposite films with different loading contents (2, 4, and 6 wt.%), and they were tested by performing the following assays: the FTIR test, the antibacterial, soil burial test, DSC, AFM, and SEM. The results showed an improvement of the membranes in the antibacterial properties for both Escherichia coli (E. coli, Gram-negative) and Staphylococcus aureus (S. aureus, Gram-positive) when nano-ZnO was added. The biodegradation through weight loss was observed for all samples, and the results showed that the weight loss increased with the increase in ZnO nanoparticle content from 2% to 6% wt. The DSC results showed that the addition of ZnO led to an increase in Tg, and increasing the degree of glass transition led to an increase in the degradation rate. In the FTIR results, only physical interference was observed; no chemical interference was evident. The AFM results showed some agglomerations of nano-ZnO in the PVA matrix led to an increase in the surface roughness of the PVA/nano-ZnO film.

Computational Study of Network and Type-I Functional Divergence in Alcohol Dehydrogenase Enzymes Across Species Using Molecular Dynamics Simulation.

Alcohol dehydrogenases (ADHs) are critical enzymes involved in the oxidation of alcohols, contributing to various metabolic pathways across organisms. This study investigates type I functional divergence within three ADH1 families: Saccharomyces cerevisiae (PDB ID: 4W6Z), Gadus morhua (PDB ID: 1CDO), and Homo sapiens (PDB ID: 1HDX). Understanding the molecular evolution and mechanisms underlying functional divergence of ADHs is essential for comprehending their adaptive significance. For this purpose, we performed a computational analysis that included structural characterization of ADHs through three-dimensional modeling, site-specific analysis to evaluate selective pressures and evolutionary constraints, and network analysis to elucidate relationships between structural features and functional divergence. Our findings indicate substantial variations in evolutionary and structural adaptations among the ADH families.

Photocatalytic Substrate Oxidation Catalyzed by a Ruthenium(II) Complex with a Phenazine Moiety as the Active Site Using Dioxygen as a Terminal Oxidant.

We have developed photocatalytic oxidation of aromatic substrates using O2 as a terminal oxidant to afford only 2e--oxidized products without the reductive activation of O2 in acidic water under visible-light irradiation. A RuII complex (1) bearing a pyrazine moiety as the active site in tetrapyrido[3,2-a:2',3'-c:3″,2″-h:2‴,3‴-j]phenazine (tpphz) as a ligand was employed as a photocatalyst. The active species for the photocatalysis was revealed to be not complex 1 itself but the protonated form, 1-H+, protonated at the vacant diimine site of tpphz. Upon photoexcitation in the presence of an organic substrate, 1-H+ was converted to the corresponding dihydro-intermediate (2-H+), where the pyrazine moiety of the ligand received 2e- and 2H+ from the substrate. 2-H+ was facilely oxidized by O2 to recover 1-H+. Consequently, an oxidation product of the substrate and H2O2 derived from dioxygen reduction were obtained; however, the H2O2 formed was also used for oxidation of 2-H+. In the oxidation of benzyl alcohol to benzaldehyde, the turnover number reached 240 for 10 h, and the quantum yield was determined to be 4.0%. The absence of ring-opening products in the oxidation of cyclobutanol suggests that the catalytic reaction proceeds through a mechanism involving formal hydride transfer. Mechanistic studies revealed that the photocatalytic substrate oxidation by 1-H+ was achieved in neither the lowest singlet excited state nor triplet excited state (S1 or T1) but in the second lowest singlet excited state (S2), i.e., 1(π-π*)* of the tpphz ligand. Thus, the photocatalytic substrate oxidation by 1-H+ can be categorized into unusual anti-Kasha photocatalysis.

Novel Inorganic-Organic Dual-Photosensitizing Dinuclear-Metal Self-Assembly System for Efficient Artificial Photosynthesis without Sacrificial Electron Donors.

Owing to the unique synergistic effect, dinuclear-metal-molecule-catalysts (DMCs) show excellent performance in catalytic fields. However, for overall photocatalytic CO2 reaction (CO2RR), it is still a challenge to construct well-matched photosensitizer (PS) components for DMCs-based photocatalysts. Inorganic-quantum-dot PS possesses capacities of multiple exciton generation and catalyzing water oxidation but is incompatible with DMCs. In contrast, organic PS can be covalently linked with DMCs but inescapable of using sacrificial electron donors. For overall photocatalytic CO2RR, organic-inorganic dual-photosensitizing system might be a promising candidate. Herein, we employed covalent-linking and electrostatic-driven approaches to construct the self-assembly of pyrene-sensitized Co2L DMCs (Py-Co2L) and perovskite (PVK) quantum dots, i.e., PVK@[Py-Co2L]. Using H2O as an electron donor, PVK@[Py-Co2L] realized 105.24 μmol ⋅ g-1⋅h-1 CO yield in photocatalytic CO2RR, much higher than PVK (15.44 μmol ⋅ g-1⋅h-1) and PVK@Co2L (32.30 μmol ⋅ g-1 ⋅ h-1), ascribing to the efficient photogenerated charge separation and transfer. The experimental results and theoretical investigations demonstrated that the pyrene linked on Co2L boosted the electron delivery from PVK to DMCs. Besides, this strategy could also be extended to the photocatalytic H2 evolution coupled with alcohol oxidation. As a proof-of-concept, our work lightens the integration of DMCs, organic and inorganic PS components, promoting the development of photocatalysis without sacrificial electron donors.

Novel Inorganic‐Organic Dual‐Photosensitizing Dinuclear‐Metal Self‐Assembly System for Efficient Artificial Photosynthesis without Sacrificial Electron Donors

AbstractOwing to the unique synergistic effect, dinuclear‐metal‐molecule‐catalysts (DMCs) show excellent performance in catalytic fields. However, for overall photocatalytic CO2 reaction (CO2RR), it is still a challenge to construct well‐matched photosensitizer (PS) components for DMCs‐based photocatalysts. Inorganic‐quantum‐dot PS possesses capacities of multiple exciton generation and catalyzing water oxidation but is incompatible with DMCs. In contrast, organic PS can be covalently linked with DMCs but inescapable of using sacrificial electron donors. For overall photocatalytic CO2RR, organic–inorganic dual‐photosensitizing system might be a promising candidate. Herein, we employed covalent‐linking and electrostatic‐driven approaches to construct the self‐assembly of pyrene‐sensitized Co2L DMCs (Py‐Co2L) and perovskite (PVK) quantum dots, i.e., PVK@[Py‐Co2L]. Using H2O as an electron donor, PVK@[Py‐Co2L] realized 105.24 μmol ⋅ g−1⋅h−1 CO yield in photocatalytic CO2RR, much higher than PVK (15.44 μmol ⋅ g−1⋅h−1) and PVK@Co2L (32.30 μmol ⋅ g−1 ⋅ h−1), ascribing to the efficient photogenerated charge separation and transfer. The experimental results and theoretical investigations demonstrated that the pyrene linked on Co2L boosted the electron delivery from PVK to DMCs. Besides, this strategy could also be extended to the photocatalytic H2 evolution coupled with alcohol oxidation. As a proof‐of‐concept, our work lightens the integration of DMCs, organic and inorganic PS components, promoting the development of photocatalysis without sacrificial electron donors.

Bases Tuning Selective Aerobic Oxidation of Benzyl Alcohol to Benzaldehyde Catalyzed by Cu2+/TEMPO

Bases Tuning Selective Aerobic Oxidation of Benzyl Alcohol to Benzaldehyde Catalyzed by Cu2+/TEMPO

Preparation and Catalytic Properties of Gold Single-Atom and Cluster Catalysts Utilizing Nanoparticulate Mg-Al Layered Double Hydroxides.

Au single atoms and clusters were stabilized on Mg-Al layered double hydroxide nanoparticles (LDH NPs), and the obtained Au@LDH NPs were supported on SiO2 and CeO2. After hydrogen reduction, Au single atoms were found together with Au clusters on LDH/SiO2. In contrast to Au single-atom catalysts which are deposited in metal vacancies of oxide supports, the LDH NPs stabilize very small Au species despite the absence of metal vacancies. The obtained Au(0)@LDH/SiO2 catalyzed aerobic oxidation of alcohols, and Au single atoms maintained after the reaction. Given that only Au NPs were observed on bulk LDH, the abundant surface OH group of LDH NPs would contribute to stabilize Au, resulting in higher activity than Au/LDH-bulk. After calcination to transform LDH to mixed metal oxide (MMO), the obtained Au(0)@MMO/SiO2 also exhibited high catalytic activity. Moreover, Au(0)@LDH/CeO2 exhibited higher activity and excellent selectivity for hydrogenation of 4-nitrostyrene to 4-aminostyrene than conventional Au catalysts such as Au/CeO2 and Au/TiO2. We demonstrated that Au size can be minimized using LDH NPs, exhibiting high catalytic performance. The basic surface OH groups of LDH would be also beneficial for deprotonation of alcohols and heterolytic dissociation of H2 in the catalytic reactions.

Aerobic Oxidation of Alcohols and Olefins Using Ru NPs Decorated on Functionalized PNIPAM Grafted Magnetic Nanoparticles

ABSTRACTA thermo‐responsive ruthenium catalyst was produced by immobilizing poly(N‐isopropyl acrylamide) on the silica surface coated iron oxide nanoparticles (Fe3O4@Si). After being exposed to ethylenediamine, the amino‐modified support (Fe3O4@Si‐PNIPAM‐NH2) was produced, and Fe3O4@Si‐PNIPAM‐NH2‐EDTA was made in the ensuing reaction with EDTA (ethylenediaminetetraacetic acid). Ru NPs were introduced to the modified magnetic support to create a well‐organized heterogeneous catalytic system with several advantages, such as enabling catalyst recycling and simple separation. This new catalyst was characterized by means of various techniques, including TGA, ICP, FT‐IR, DLS, TEM, SEM, EDX, VSM, XRD, CHN, and XPS. In the presence of H2O2 or air alone, this catalyst showed a significant effect in the oxidation of various alcohols to the corresponding aldehydes or ketones. Furthermore, the catalyst exhibited outstanding capacity in the aerobic oxidation of olefines to the carbonyl or oxirane counterparts. A main aspect of this catalytic system is the reusability of the catalyst at least eight times in consecutive runs without causing any discernible loss of activity, structural change, or leaching.

A New CuI/Oxalamide Catalytic System for the Large‐Scale Aerobic Oxidation of Alcohols

AbstractSince the report of oxamide ligands, they have been widely used for the efficient construction of various types of C−X (such as C, N, O and S) bonds. To evaluate whether the easily tunable electronic properties and unique coordination modes of oxamide ligands can also shine in the field of oxidation, we initiated a study on oxamide ligand/copper/air oxidation and applied it to the oxidation of alcohols to assess its practicality and potential applications. The practicality of this strategy was further verified through scale‐up reactions on a 100 mmol scale and gram‐scale derivatization of pharmaceutical molecules.

Nanocellulose‐reinforced, anti‐freezing, highly conductive ionic organic hydrogels for flexible electronic devices

AbstractCurrently, flexible electronic devices based on ionic conductive hydrogels are receiving widespread attention in the field of human health detection. In this paper, a facile one‐pot method is proposed for the preparation of ionic organic hydrogels, in which polyvinyl alcohol (PVA), cellulose nanofiber (CNF), and graphene oxide (GO) are dissolved in dimethyl sulfoxide‐water (DMSO/H2O), and the organic hydrogel is obtained by a freezing–thawing process. The ionic organic hydrogel with excellent properties is then prepared by soaking the hydrogel in a calcium chloride (CaCl2) solution using a salting‐out strategy. The ionic organic hydrogel possesses good tensile (283%) and strength (0.3 MPa), super electrical conductivity (7.72 S/m), and high strain sensitivity [gauge factor (GF) up to 5.22]. Meanwhile, it has excellent anti‐freezing and moisturizing properties. In addition, the ionic organic hydrogels can be used in flexible strain sensors and triboelectric nanogenerators to realize real‐time monitoring of human motion, traceless writing, and energy conversion. It is foreseen that the prepared ionic organic hydrogels provide a feasible method for realizing the long‐term use of wearable electronic devices in extreme environments and daily life.

Efficient and selective oxidation of alcohols and hydrocarbons catalyzed by oxovanadium(IV) unsymmetrical salophen complex supported on silica-coated CoFe2O4 magnetic nanoparticles

Efficient and selective oxidation of alcohols and hydrocarbons catalyzed by oxovanadium(IV) unsymmetrical salophen complex supported on silica-coated CoFe2O4 magnetic nanoparticles

Platinum and CeO2−x Occlusion Electrodeposition at Unsupported Vulcan XC-72R for Methanol and Ethanol Oxidation Reactions in Alkaline Media

Platinum was electrodeposited in a slurry solution of CeO2 and Vulcan XC-72R to produce Pt/CeO2−x/Vulcan XC-72R catalysts by using the Rotating Disk Slurry Electrodeposition (RoDSE) Technique. The activity of the catalysts was measured towards methanol and ethanol oxidation reactions in alkaline conditions by cyclic voltammetry and chronoamperometry. The electrochemical results were compared to those obtained on commercial catalysts. Pt/CeO2−x/Vulcan XC-72R (with ∼ 26 wt% Pt) catalyst was the most active for both alcohol oxidation reactions when compared to commercial 40 wt.% and 20% /Vulcan XC-72R (ETEK) catalysts. The mass activity increases 2.0x and 2.4x for methanol and ethanol oxidation reactions when compare with 40 and 20 Pt wt. % commercial catalysts, respectively. The Pt/CeO2−x/Vulcan XC-72R catalysts contained Pt nanoparticles growth within the cerium oxide through an occlusion electrodeposition method. These effects were systematically investigated using X-ray Diffraction (XRD), High Resolution Transmission Electron Microscopy (HR-TEM), and X-ray Photoelectron Spectroscopy (XPS).

Recent Progress in Situ Application of H2O2 Produced via Catalytic Synthesis.

Industrial production of H2O2 requires lots of energy and causes environmental pollution. Moreover, in subsequent applications, much economic loss could be produced during the transportation process of H2O2 and its dilution process. Therefore, it is highly desirable for in situ application of H2O2. In recent years, catalytic synthesis of H2O2, e. g., direct catalytic synthesis, electrocatalytic synthesis, and photocatalytic synthesis, has attracted more and more attention because the continuous and low-concentration H2O2 produced by catalytic synthesis can be directly used for the oxidation of organic compounds, effectively avoiding the shortcomings of the current industrial route. Here, we briefly reviewed the latest processes for the catalytic production of H2O2 via various routes. On this basis, we summarized and discussed the in situ application of H2O2 in typical organic conversion reactions, including the ammoximation of ketones, the oxidation of alcohols, the oxidation of C-H bonds, and the oxidation of olefins. Some in situ coupling reactions have shown excellent performance with high conversion and selectivity, and the economic cost has been significantly reduced. Finally, the shortcomings of the in situ utilization of H2O2 in coupling reactions were analyzed, and some strategies for promoting the efficiency of the H2O2 application in organic synthesis were proposed.

Constructing organic-inorganic woven hybrid membrane for highly-selective catalytic conversion of lignin-based phenolic molecule to value-added products

Addressing the global need for sustainable chemical processes, this study introduces an innovative Woven Hybrid Membrane (WHM) specifically designed for the efficient oxidation of vanillyl alcohol (VAA) to vanillin (VLN). This transformation is crucial for converting lignocellulosic biomass into valuable chemical products, aligning with sustainable development goals. Utilizing a novel catalytic system that combines 2,2,6,6-tetramethylpiperidine 1-oxyl (TMP) and copper on a unique mesh-like structure, the WHM enhances both the economic and environmental viability of the process. This design not only overcomes the limitations of powdered catalysts, which are challenging to recover and reuse, but also promotes high catalytic efficiency and selectivity. By employing oxygen as the oxidant, our system maintains near 100% selectivity for VLN, demonstrating high conversion rates across multiple cycles without significant degradation in performance. Advanced analytical techniques, including electrochemical analysis and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), were used to explore the catalyst's functionality and the reaction mechanism. The results confirm the stability and effectiveness of the WHM, showcasing its potential as a reusable, highly efficient, and environmentally friendly catalyst. This research represents a significant step forward in the field of sustainable industrial chemistry, offering a robust solution for the bio-refinery industry's push towards greener processes.

Right iliac deep vein thrombosis and pulmonary embolism associated with recreational nitrous oxide: a case report

BackgroundThe recreational use of nitrous oxide is becoming increasingly common among teenagers and young adults. Since 2018, the use of nitrous oxide has increased exponentially and has become a public health problem.Case presentationA 23-year-old patient was referred to accident and emergency (A&E) by his general practitioner for deterioration in general condition, vomiting, diarrhea and febrile headache at 39 °C.He reported that he had been partying for a month and consuming alcohol, cannabis and nitrous oxide. Three days before the consultation, he reported increased abdominal pain in the right iliac fossa. His homocysteine concentration was 51.9 μmol/L, and his plasma methyl malonate concentration increased to 4.45 μmol/L. A thoracic and abdominal CT scan revealed right iliac venous thrombosis associated with bilateral pulmonary embolism.ConclusionNitrous oxide inhibits the activity of methionine synthetase. We therefore observed an increase in plasma homocysteine and 5-methyl-THF. The increase in homocysteine could be responsible for the pro-thrombotic activity resulting from nitrous oxide intoxication. At present, no threshold or duration of exposure has been identified as being particularly likely to cause complications. It is likely that other factors coexist, such as coagulation disorders and polymorphisms of the MHTFR gene, which can lead to hyperhomocysteinaemia, cannabis consumption, inflammatory conditions and others. Treatment is based on vitamin B12 supplementation and curative anticoagulation. Some authors also recommend folate supplementation.Consumption of nitrous oxide could be associated with arterial and venous thromboembolic disease.

Selective Oxidation of Alcohols to Carbonyls Under Decatungstate-Mediated Photoelectrochemical Conditions.

The oxidation of alcohols to the corresponding carbonyl derivatives has been realized under photoelectrochemical conditions in the presence of tetrabutylammonium decatungstate (TBADT) as the homogeneous photocatalyst. The protocol can be applied to both primary and secondary, benzylic and aliphatic alcohols. The desired products are obtained selectively, skipping the need for purposely added chemical oxidants. An in-depth study of photoelectrochemical conditions revealed that the protocol works best under amperostatic conditions in an undivided electrochemical cell irradiated with a 390 nm LED lamp. The comparison with analogous electrochemical and chemical oxidant-promoted photocatalytic transformations demonstrates the superior efficiency and selectivity of the hereby reported photoelectrochemical conditions.

Photocatalyst Design Principles for Photocatalytic Hydrogen Production and Benzyl Alcohol Oxidation with CdS Nanosheets

Photocatalyst Design Principles for Photocatalytic Hydrogen Production and Benzyl Alcohol Oxidation with CdS Nanosheets

Silica coated N-doped carbon modified with ruthenium nanoparticles: An effective waste derived carbon nanocatalyst in oxidation reactions and also its evaluation by DFT and anti-bacterial studies

This report presents the development of an inexpensive mesoporous nanocatalyst i.e. silica coated N-doped carbon modified with ruthenium nanoparticles (Ru/RuO2@NSAC). The carbon and nanosilica components were derived from waste materials namely waste tea extract and rice husk respectively highlighting the sustainable approach to the synthesis process. The nanocatalyst was thoroughly characterized using various advanced techniques such as Fourier transform infrared spectroscopy (FTIR), Powder X-ray diffraction (P-XRD), Field emission gun-scanning electron microscopy (FEG-SEM), Energy dispersive X-ray analysis (EDX), High resolution-transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) surface area analysis, X-ray resonance fluorescence (XRF) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). These characterizations provided comprehensive insights into the structural features of the nanocatalyst. XPS analysis confirmed the presence of both metallic ruthenium and Ru (IV) on the nanocatalytic support. The particle size of Ru/RuO2@NSAC was determined using Scherrer's equation and came out to be 21.37 nm. This nanocatalyst demonstrated remarkable performance as a robust heterogeneous catalyst for the oxidation of alkylarenes and alcohols to their corresponding carbonyl compounds. It exhibited excellent recyclability, maintaining its activity for up to five consecutive runs. Post-recycling, the catalyst was again characterized by P-XRD and FEG-SEM to ensure its structural integrity. Additionally, the antibacterial activity of Ru/RuO2@NSAC was evaluated against both Gram-positive and Gram-negative bacteria. A density functional theory study was also conducted to support the experimental findings, providing a theoretical basis for the observed catalytic behavior.