Oxidation Of 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.

Sub-nanometric ruthenium clusters prepared by solid-state dispersion for catalytic selective aerobic oxidation of aromatic alcohols

The selective aerobic oxidation of alcohols to corresponding aldehydes is one of the most important challenges in the green chemical industry. In this work, Ru/Al2O3-SSD catalyst with highly dispersed metallic ruthenium clusters (average particle size of 0.97 nm) was prepared by solid-state dispersion (SSD) for efficient selective aerobic oxidation of aromatic alcohols to aldehydes. Compared with the counterpart catalyst Ru/Al2O3-IM prepared by wet impregnation (IM), this catalyst has smaller metal particles (0.97 nm vs. 3.4 nm), resulting in a special electronic structure, and exhibits much higher TOF (234 h−1 vs. 98 h−1) in the aerobic oxidation reaction of benzyl alcohol at 80 °C. The catalyst also shows excellent catalytic activity in the preparation of vanillin by selective aerobic oxidation of vanillyl alcohol at 100 °C, delivering a vanillin yield of 99%. The solid-state dispersion strategy provides an efficient and facile way for the fabrication of high-performance sub-nanometric metal catalysts.

Role of non-redox innocent ligand units in the oxidation of alcohols with H2O2 catalyzed by μ-oxido-diiron(III) bis-phenolato polypyridyl complexes

Redox non-innocent ligands hold the potential to expand the redox chemistry and activity of transition metal catalysts. The impact of the additional redox chemistry of phenol ligands in oxidation catalysis is explored here in the complex μ-oxido-diiron(III) polypyridyl (1) [(L)Fe(III)(μ–O)Fe(III)(L)](ClO4)2 (where HL is 2-(((di(pyridin-2-yl)methyl) (pyridin-2-ylmethyl) amino)methyl)phenol) and its tert-butyl substituted analog 2, in which each of the Fe(III) centers is coordinated to a phenolato moiety of the ligand. Complex 1 was shown earlier to catalyse the oxidation of benzyl alcohols to aldehydes with H2O2. In particular acid was found to accelerate the reactions by removal of a lag period before catalysis initiated. Here, we use reaction monitoring with resonance Raman, UV/vis absorption and EPR spectroscopy to show that under catalytic conditions, i.e. with excess H2O2, rapid (< 5 s) loss of the phenolato moiety occurs, resulting in the formation of an N4 ligated Fe(III) complex. This N4 coordinated complex forms a Fe(III)-OOH species, which is responsible for alcohol oxidation and over time a relatively stable oxido-bridged dinuclear Fe(III) complex forms as a resting state in the catalytic system. The main role of acid in the catalysis is shown to be to facilitate the initial coordination of H2O2 by driving the formation of mononuclear complexes from 1 and 2. The data show that although the phenolato moiety imparts interesting redox properties on complex 1, it does not contribute directly to the oxidation catalysis observed with H2O2.

Synthesis and characterization of Zn-In-S composites for photocatalytic benzyl alcohol oxidation and nitrobenzene reduction

Photocatalytic transformation of organics is a promising alternative to conventional synthetic methodologies. ZnIn2S4 is active in photocatalytic redox reactions, but its performance is hindered by fast charge carrier recombination, and optimizing its properties through synthesis or modification is complicated. Herein, Zn-In-S based composites were prepared via a facile solvothermal method by varying the ratio of sulfide precursor (TAA) with a fixed Zn/ In molar ratio of 1: 2. The phase composition of the obtained materials depends on the amount of TAA. At lower ratios, composites consisting of crystalline In(OH)3 and unknown ZnxInySz phase were formed. Pure-phase ZnIn2S4 was obtained when the feed molar ratio of zinc and TAA was 1: 6 or higher. The photocatalytic oxidation of benzyl alcohol (BA) and reduction of nitrobenzene (NB) in a coupled system were applied to evaluate the activity of Zn-In-S-based composites. Under visible light irradiation, the ZnxInySz/ In(OH)3 composite (ZIS14) synthesized with a molar ratio of Zn to TAA of 1: 4 exhibited boosted and optimal performance compared to the bare ZnIn2S4 and other samples. After 5 hours of irradiation, the BA conversion and benzaldehyde (BAD) yield were 57 % and 55 %, respectively, and the NB conversion and aniline (AN) yield were 70 % and 35 %, individually, outperforming previous studies under similar experimental conditions. This work not only elucidates the photoredox process of BA and NB in one system, but also has significant implications for understanding the complex hydro/solvothermal processes involved in the fabrication of multicomponent sulfides.

Heterogeneous Recyclable Fiber-Supported TEMPO Catalyst for Highly Selective Aryl Alcohols Oxidation

Heterogeneous Recyclable Fiber-Supported TEMPO Catalyst for Highly Selective Aryl Alcohols Oxidation

Ceria nanocatalyst-supported oxidative organic transformations of aromatic alcohols and p-nitrotoluene

Hydrothermally derived nanocubes of CeO2(10 nm) were explored as an efficient heterogeneous catalyst in the partial oxidation of aromatic alcohols to the corresponding aldehydes and aerobic oxidation ofp-nitrotoluene top-nitrobenzoic acid. The CeO2nanocatalyst was characterized by x-ray diffraction, transmission electron microscopy (TEM), energy dispersive spectroscopy, x-ray photoelectron spectroscopy, Brunauer-Emmett-Teller (BET) surface area analysis, Fourier transform infrared spectroscopy, thermal gravimetric analysis and ultraviolet-visible spectroscopy. TEM/high-resolution TEM micrographs reveal a morphology of mostly cubic nanostructures with exposed highly active {100} and {110} facets. The surface area of nanoceria was determined by BET analysis and found to be 33.8 m2g-1. To demonstrate the universality of the catalytic system, the selective oxidation of different substrates of benzylic alcohol and complete oxidation ofp-nitrotoluene was investigated under mild conditions. Absolute selectivity towards their respective aldehydes was found to be 99.50% (benzaldehyde), 90.18% (p-chlorobenzaldehyde), 99.71% (p-nitrobenzaldehyde), 98.10% (p-fluorobenzaldehyde), 94.66% (p-anisaldehyde) and 86.14% (cinnamaldehyde). Moreover, the catalytic oxidative transformation of nitrotoluene results in 100% conversion with 99.29% selectivity towards nitrobenzoic acid.

Catalytic oxidation of alcohols catalyzed by gold-coated iron oxide magnetic nanoparticles in water

Catalytic oxidation of alcohols catalyzed by gold-coated iron oxide magnetic nanoparticles in water

Constructing p-n heterojunctions of Cl-Cu2O and PANI on three-dimensional nanofiber networks for enhanced photocatalytic degradation of oxytetracycline

A p-n heterojunction was constructed on a bacterial cellulose (BC) film by combining n-type semiconductor chlorine-doped Cu2O (Cl-Cu2O) and p-type semiconductor polyaniline (PANI), creating a ternary composite flexible film of Cl-Cu2O/PANI/BC. The chemical structure, microscopic morphology, and photoelectrochemical properties of Cl-Cu2O/PANI/BC were characterized and analyzed. Compared with pure Cl-Cu2O, the Cl-Cu2O/PANI/BC composite flexible film exhibited a broader response range to visible and near-infrared light, higher carrier concentration, lower impedance value, and substantial reduction in the recombination probability of photogenerated carriers. The process conditions for the photocatalytic degradation of oxytetracycline (OTC) were optimized using the response surface method, and the degradation rate of OTC caused by the Cl-Cu2O/PANI/BC was 96.3 %. In the degradation process of OTC, superoxide radical is the main active species. It was found that OTC molecules degraded via demethylation, secondary alcohol oxidation, decarboxylation, and deamination reactions, finally being degraded into H2O, CO2, and other small organic molecules. Thirteen major intermediates and possible degradation pathways were speculated. The photocatalytic performance of the Cl-Cu2O/PANI/BC was improved owing to the successful construction of the p-n heterojunction. The built-in electric field generated at the interface between the two semiconductors promoted the diffusion of photogenerated holes from the n-type Cl-Cu2O particles to the PANI coating layer on the BC chain, whereas the photogenerated electrons from PANI diffused toward Cl-Cu2O, accelerating the separation efficiency of photoinduced electrons and holes in the two semiconductors and thereby improving the efficiency of photocatalytic degradation. In addition, the three-dimensional network structure of a composite flexible film can help recover the photocatalyst. After performing seven experiments for recovery and reuse, the photocatalytic degradation rate of OTC still remained above 90 %.

Biosynthetic Strategies of Berberine Bridge Enzyme-like Flavoprotein Oxidases toward Structural Diversification in Natural Product Biosynthesis.

Berberine bridge enzyme-like oxidases are often involved in natural product biosynthesis and are seen as essential enzymes for the generation of intricate pharmacophores. These oxidases have the ability to transfer a hydride atom to the FAD cofactor, which enables complex substrate modifications and rearrangements including (intramolecular) cyclizations, carbon-carbon bond formations, and nucleophilic additions. Despite the diverse range of activities, the mechanistic details of these reactions often remain incompletely understood. In this Review, we delve into the complexity that BBE-like oxidases from bacteria, fungal, and plant origins exhibit by providing an overview of the shared catalytic features and emphasizing the different reactivities. We propose four generalized modes of action by which BBE-like oxidases enable the synthesis of natural products, ranging from the classic alcohol oxidation reactions to less common amine and amide oxidation reactions. Exploring the mechanisms utilized by nature to produce its vast array of natural products is a subject of considerable interest and can lead to the discovery of unique biochemical activities.

Material Dynamics of Nickel (oxy)Hydroxide As an Alcohol Oxidation Electrocatalyst

Electrochemical alcohol oxidation is an attractive reaction for renewable-energy driven production of value-added chemicals, like precursors for acrylic (acrolein from glycerol) and nylon (adipic acid from cyclohexanol). Implementing selective, earth-abundant catalysts for alcohol oxidation can improve electrolyzer efficiency and economics. For example, replacing the energy intensive oxygen evolution reaction (OER) in CO2 electrolyzers with alcohol oxidation can decrease operating voltage by about 0.85 V and reduce electricity requirements up to 53% while also reducing carbon emissions from chemical production.1 Electrochemical alcohol oxidation catalyzed by as synthesized nickel oxyhydroxide (NiOOH) is hypothesized to proceed through two pathways, a chemical, redox pathway preferred by aldehydes (geminal diols in alkaline electrolyte), and a potential dependent pathway preferred by alcohols.2 Many studies have focused on understanding reaction mechanisms and device performance, however, transition metal alcohol oxidation catalysts, such as NiOOH, are known to undergo reduction/oxidation, phase changes, and even dissolution in the same potential window as alcohol oxidation.3 It is still unclear how these processes affect catalyst material stability and electrochemical performance.In this work, we probe the performance stability and material stability of Ni(OH)2 for alcohol oxidation in alkaline media through electrochemical cycling and chronoamperometry. We use a rigorously Fe-free environment to mitigate performance impacts from Fe-contamination common in non-purified alkaline electrochemical studies.4 We show that the rate of change of alcohol oxidation current density (mA cm-2) depends on reaction pathway (redox vs. potential dependent), alcohol concentration, and side chain structure. Using EC-MS and NMR, we also probe changes in performance in yield and selectivity by quantifying oxidation products, including oxygen gas. These changes in performance are correlated to material changes through monitoring dissolution with on-line ICP-MS. Furthermore, to disentangle the role of potential and reactant (e.g. alcohol or water) on stability, we elucidate oxidation state and local structural changes using in situ X-ray Absorption Spectroscopy (XAS). Insights from this rigorous model system are directly translatable to the broader goal of developing efficient, long-lasting catalysts for industrial deployment of electrochemical organic reactions powered by clean energy. References. Verma, Sumit, Shawn Lu, and Paul JA Kenis. Nature Energy 4.6 (2019): 466-474.2.Bender, Michael T., and Kyoung‐Shin Choi. ChemSusChem 15.13 (2022): e202200675.Klaus, Shannon, et al. The Journal of Physical Chemistry C 119.13 (2015): 7243-7254Wei, Lingze, et al. ACS Catalysis 13.7 (2023): 4272-4282.

Mesoporous g-C3N4/ZnFe2O4/TCPP nanocomposite for selective liquid-phase oxidation of alcohols to aldehydes under visible light irradiation

This study provides a viable strategy for the production of aromatic benzaldehydes by a three-component magnetic recoverable photocatalyst. The novel photocatalyst was fabricated by modification of Graphitic carbon nitride (g-C3N4) using ZnFe2O4 magnetic nanoparticles and Tetrakis(4-carboxyphenyl)porphyrin (TCPP) and labeled as CFP where C is the carbonic substrate, F shows the magnetic component and P demonstrated TCPP porphyrin. The optimized CFP photocatalyst demonstrated approximately 96 % conversion and 99 % selectivity for the oxidation of benzyl alcohol to benzaldehyde. The photocatalytic reaction carried out in the presence of acetonitrile and H2O2 as solvent and oxidant under LED lamp (15 W) irradiation. The results reveal that the values of conversion and selectivity of various types of benzylic alcohols are attributed to the aromaticity and position of substituents on the benzene ring. The reusability of CFP photocatalyst was investigated up to the fourth cycle, and it revealed any significant loss of photocatalytic oxidation activity, which is related to high structural stability of photocatalyst.

Value-Added Electrolysis Hydrogen Production Via Methanol Oxidation over a Synergetic Pt1-W Dual-Site Catalyst

Electrochemical water splitting is a promising way of generating hydrogen for future sustainable green energy source technology options to replace nonrenewable and environmentally pollutant hydrocarbon energy sources. However, due to its high overpotential in oxygen evolution reaction (OER) and low-value product O2, some candidate anodic reactions with low potential should be proposed to replace OER, such as alcohol oxidation. Unlike fuel cell applications, partial oxidation is preferred to achieve high-value products rather than complete oxidation. For this purpose, we design a synergistic effect Pt1-W site on the dual-doped TiO2 support (Ti0.8W0.2NxOy) to catalyze alkaline methanol oxidation and gain 90% selectivity of formate production. Comparing the case of the Pt nanoparticles (69% selectivity of formaldehyde), the Pt single-atom catalyst controls selectivity and enhances the reactivity and stability attributed to the strong catalyst-support interaction. As a result, this work shows a novel strategy for electrochemical hydrogen production at far lower anodic potential by designing a stable and efficient Pt-based single-atom catalyst.

(Invited) The Activation of Alkanes at Electrochemical Interfaces Using Real-Time Control of Potentials: Novel Avenues for Energy Storage and Sustainable Chemical Manufacturing

Producing fuels and chemicals using renewable electricity holds the promise to enable a truly sustainable circular economy based on sustainably produced carriers of electrical energy and sustainably produced chemicals. The science which allows us to link electricity to chemical transformations, electrocatalysis, remains chiefly focused on the electricity-driven transformation of small inorganic molecules such as CO2, H2O, N2, as well as the oxidation and reduction of alcohols. However, comprehensive electrification of society will require electrocatalytic reactions that can promote the central processes that sustain today’s society: alkane transformations. In this presentation, I will show how fundamental understanding of the interfacial processes occurring in electrocatalytic reactions, combined with monolayer-sensitive differential electrochemical mass spectrometry, allows us to independently control the elementary steps (adsorption, transformation, desorption) of complex alkane transformation reactions, allowing for the room-temperature fragmentation of ethane into methane, as well as for enabling the extraction of the chemical energy stored in alkanes in the form of electricity. I will show how we can apply these technologies to expand the reaction scope of electrocatalysis, allowing for novel avenues in energy storage, chemical synthesis and plastics recycling.

Investigating the pH-Dependent Activity, Selectivity, and Dynamics of Metal Nitride Electrocatalysts for Fuel Cells and Electrolyzers

To mitigate climate change caused by the use of fossil fuel energy sources, there is an urgent need to decarbonize our energy systems. Developing fuel cell and water electrolysis technologies to support a green hydrogen infrastructure is a promising strategy for this transition. In both hydrogen fuel cells and water electrolyzers, platinum-group metal (PGM) materials such as Pt and IrOx are benchmark electrocatalysts, exhibiting high activity and stability for kinetically-hindered reactions including the oxygen reduction reaction (ORR), the oxygen evolution reaction (OER), and alcohol oxidation reactions (AOR; alternative anodic reactions to OER). Despite their remarkable performance, the high cost and low abundance of PGMs is a key factor limiting the widespread adoption of these technologies.Cobalt- and nickel-based metal and oxide catalysts have emerged in the literature as a promising PGM-alternative class of low-cost, high-performing ORR, OER and AOR catalysts. Substituting oxides with nitrides or other chalcogenides could be a favorable method to improve activity, selectivity, and stability; however, the material stability of these non-oxides as a function of reaction, potential window, and pH is not well-understood. Furthermore, the most active of these materials tend to be carbon-supported nanoparticles with complicated and heterogeneous active sites, which makes deconvoluting the role of the cobalt and secondary element(s) (e.g. N, C, etc.) difficult.With the goal of developing fundamental activity-stability relationships for non-precious metal-based electrocatalysts, we have developed a synthesis procedure for well-defined Co- and Ni-based thin film materials. Focusing on Co, using physical vapor deposition followed by thermal treatments with ammonia and an Sb-based precursor, we have synthesized CoxSbyNz thin films of varying compositions. These synthesis methods can be extended to synthesize a broad class of metallic (Co, Ni, Fe, etc.) or bimetallic X-ide (X = N, S, etc.) thin film materials. We evaluate ORR, OER, and AOR activity with cyclic voltammetry, demonstrating that activity depends on composition and electrolyte pH. Specifically, for Co-based thin films for ORR, we see improvement in activity with the incorporation of N, and improvement in acid-stability with the incorporation of Sb. In addition to ex situ post-characterization with x-ray photoelectron spectroscopy, we utilize in situ techniques to evaluate catalyst stability in real time. We monitor time- and potential-dependent cobalt dissolution with an on-line inductively coupled plasma mass spectrometer (ICP-MS) as well as nitride degradation with electrochemical mass spectrometry (EC-MS). In acidic media, the stability of CoxN is limited by Co dissolution, while in alkaline media stability appears to be limited by nitride degradation. With highly active non-oxide materials it is typically too complicated to disentangle the role of each individual element within an electrocatalyst. With our stepwise material synthesis platform and multifaceted characterization techniques we are able to individually probe the material stability and product-specific activity of each element. These results provide new insights to guide the strategic design of electrocatalysts across a range of reactions and applications.

Covalently linked molecular catalysts in conjugated polymer dots boost photocatalytic alcohol oxidation in neutral condition

As a new class of organic photocatalysts, polymer dots show a potential application in photocatalytic hydrogen peroxide production coupled with chemical oxidation such as methanol oxidation. However, the poor methanol oxidation ability by polymer dots still inhibits the overall photocatalytic reaction occurring in the neutral condition. In this work, an organic molecular catalyst 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl radical is covalently linked to a fluorene unit in a polymer skeleton, eventually enabling photocatalytic hydrogen peroxide production coupled with methanol oxidation in the neutral condition. By conducting various spectroscopic measurements, charge transfer between components in this molecular catalyst-immobilized polymer dots system is studied and found to be very efficient for hydrogen peroxide production coupled with alcohol oxidation. This work proves a strategy for designing polymer dots photocatalysts with molecular catalysts, facilitating their future development and potential applications in other fields such as water splitting, CO2 reduction, photoredox catalysis and photodynamic therapy.

Vacancy-Engineered 1D Nanorods with Spatially Segregated Dual Redox Sites for Visible-Light-Driven Cooperative CO2 Reduction.

Cooperative CO2 photoreduction with tailored organic synthesis offers a potent avenue for harnessing concurrently generated electrons and holes, facilitating the creation of both solar fuels and specialized chemical compounds. However, controlling the crystallization and morphologies of metal-free molecular nanostructures with exceptional photocatalytic activities toward CO2 reduction remains a significant challenge. These hurdles encompass insufficient CO2 activation potential, sluggish multielectron processes, delayed charge-separation kinetics, inadequate storage of long-lived photoexcitons, unfavorable thermodynamic conditions, and the precise control of product selectivity. Here, melem oligomer 2D nanosheets (MNSs) synthesized through pyrolysis are transformed into 1D nanorods (MNRs) at room temperature with the simultaneous engineering of vacancies and morphology. Transient absorption spectral analysis reveals that vacancies in MNRs trap charges, extending charge carrier lifetimes. Additionally, carbon vacancies enhance CO2 adsorption by increasing amine functional centers. The photocatalytic performance of MNRs for CO2 reduction coupled with benzyl alcohol oxidation is approximately ten times higher (CH3OH and aromatic aldehyde production rate 27 ± 0.5 and 93 ± 0.5 mmol g-1 h-1, respectively) than for the MNSs (CH3OH and aromatic aldehyde production rate 2.9 ± 0.5 and 9 ± 0.5 mmol g-1 h-1, respectively). The CO2 reduction pathway involved the carbon-coordinated formyl pathway through the formation of *COOH and *CHO intermediates, as mapped by in situ Fourier-transform infrared spectroscopy. The superior performance of MNRs is attributed to favorable energy-level alignment, enriched amine surfaces, and unique morphology, enhancing solar-to-chemical conversion.

Nitrogen-Tungsten Oxide Nanostructures on Nickel Foam as High Efficient Electrocatalysts for Benzyl Alcohol Oxidation.

Electrocatalytic alcohol oxidation (EAO) is an attractive alternative to the sluggish oxygen evolution reaction in electrochemical hydrogen evolution cells. However, the development of high-performance bifunctional electrocatalysts is a major challenge. Herein, we developed a nitrogen-doped bimetallic oxide electrocatalyst (WO-N/NF) by a one-step hydrothermal method for the selective electrooxidation of benzyl alcohol to benzoic acid in alkaline electrolytes. The WO-N/NF electrode features block-shaped particles on a rough, inhomogeneous surface with cracks and lumpy nodules, increasing active sites and enhancing electrolyte diffusion. The electrode demonstrates exceptional activity, stability, and selectivity, achieving efficient benzoic acid production while reducing the electrolysis voltage. A low onset potential of 1.38 V (vs. RHE) is achieved to reach a current density of 100 mA cm-2 in 1.0 M KOH electrolyte with only 0.2 mmol of metal precursors, which is 396 mV lower than that of water oxidation. The analysis reveals a yield, conversion, and selectivity of 98.41%, 99.66%, and 99.74%, respectively, with a Faradaic efficiency of 98.77%. This work provides insight into the rational design of a highly active and selective catalyst for electrocatalytic alcohol oxidation.

Development of an Effective Au : Pd Bimetallic Heterogeneous Catalyst for Oxidative Lignin Depolymerization to Low Molecular Weight Aromatics

AbstractLignin, a phenolic‐rich biomass component, holds promise for producing value‐added products. However, its complex structure and recalcitrance present challenges for its effective utilization. To overcome this, a AuPd/Li−Al layered double hydroxide (LDH) catalyst was developed to facilitate lignin depolymerization. Various AuPd bimetallic nanoparticle compositions were supported on a basic Li−Al LDH support via a sol‐immobilization method and characterized using N2‐physisorption, X‐ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The catalysts were then evaluated in the oxidation of several benzylic alcohols using O2 as the oxidant, from which Au7Pd3/Li−Al LDH and Au1Pd1/Li−Al LDH were identified as possessing promising catalytic activity. Further investigations focused on the aerobic oxidation of β‐O‐4 linked lignin model dimers under atmospheric pressure. The tested catalysts demonstrated sequential oxidation of the model compounds, leading to cleavage of the β‐O‐4 linkage. Finally, the catalysts were applied to the oxidative deconstruction of γ‐valerolactone (GVL) extracted maple lignin at 120 °C. Au1Pd1/Li−Al LDH emerged as the most effective catalyst, yielding a range of aromatic monomers with a total monomer yield of 27 %. These results highlight the potential of the Au1Pd1/Li−Al LDH catalyst system as an eco‐friendly approach for lignin depolymerization under mild conditions.

High-Efficiency Photocatalytic Oxidation of Benzyl Alcohol by NH2-UiO-66-(Indole-2,3-Dione)-Fe.

The photocatalytic oxidation of biomass-derived benzyl alcohol provides a promising way for the synthesis of benzoic acid, which is an important intermediate with wide applications. To improve the efficiency of photocatalytic benzyl alcohol oxidation to benzoic acid is of great interest. In this work, we propose the utilization of NH2-UiO-66-ID-Fe catalyst for photocatalytic oxidation of benzyl alcohol to benzoic acid, where NH2-UiO-66 is a typically used metal-organic framework, ID is indole-2,3-dione (ID) that has biocompatibility, light absorption property and can be covalently combined with amino-functionalized substances. The NH2-UiO-66-ID-Fe catalyst exhibits improved light absorption and photo-generated electron-hole separation ability compared with NH2-UiO-66. The photocatalytic performance of NH2-UiO-66-ID-Fe was examined for the oxidation of bio-based benzyl alcohol under mild conditions of air atmosphere, room temperature and no additive or additional oxidant involved. The results show that the conversion of benzyl alcohol and the selectivity to benzoic acid could both reach over 99 % in 6 h, and the generation rate of benzoic acid per gram of catalyst is 3.36 mmol g-1 h-1. The reaction mechanism was detected by radical trapping method and in situ electron paramagnetic resonance. This study presents an efficient and environmentally benign avenue for the synthesis of carboxylic acid compounds.

Formation of C–C and C–N bonds through primary alcohol oxidation catalyzed by ruthenium(II) POCOP pincer complexes

In this study, we present the successful application of new and known stable 16‐electron ruthenium(II) pincer complexes POCOP, based on the naphthoresorcinate backbone, [Ru(X)(POCOP)(CO)] (X = H, Cl, Br, I, OCOCF3), in the catalytic alkylation of ketones and the coupling between amines and primary alcohols under mild conditions. These protocols demonstrated tolerance to a wide range of alcohols, ketones, and anilines, with reactions proceeding in high conversions and selectivity towards the hydrogenated ketones and the imines. The use of an excess of alcohol as the proton source facilitated the formation of the hydrogenated products. These results mark a significant advancement in the development of catalytic reactions with ruthenium POCOP pincer derivatives.