Conversion Of Benzyl Alcohol Research Articles

Lewis and Brønsted Acids Synergy in Photocatalytic Aerobic Alcohol Oxidations.

Photocatalytic chemical transformations for green organic synthesis has attracted much interest. However, their development is greatly hampered by the lack of sufficient reactive sites on the photocatalyst surface for the adsorption and activation of substrate molecules. Herein, we demonstrate that the introduction of well-defined Lewis and Brønsted acid sites coexisting on the surface of TiO2 (SO42-/N-TiO2) creates abundant active adsorption sites for photoredox reactions. The electron-deficient Lewis acid sites supply coordinatively unsaturated surface sites to adsorb molecular oxygen, and the Brønsted acid sites are liable to donate protons to form hydrogen bonds with the OH groups of alcohols like benzyl alcohol (BA). These coexistent acid sites result in a strong synergistic effect in photocatalytic aerobic oxidation of BA. For example, the conversion of BA to benzaldehyde was found to be 88.6%, being much higher than those of pristine TiO2 (14.7%), N-doped TiO2 (N-TiO2, 24.6%), sulfated TiO2 (SO42-/ TiO2, 35.4%), and even their sum. The apparent quantum efficiency (AQE) was determined to be 58.1% at 365 nm and 12.9% at 420 nm over SO42-/N-TiO2. This strategy to create effective synergistic Lewis and Brønsted acids on the catalyst surfaces enables us to apply it to other semiconducting photocatalytic organic transformations.

Selective Photocatalysis of Benzyl Alcohol Valorization by Cocatalyst Engineering Over Zn2In2S5 Nanosheets

AbstractPhotocatalytic conversion of benzyl alcohol (BA) is a promising means to coproduce H2 with value‐added chemicals. However, there is a lack of an efficient strategy to regulate the selectivity of the BA conversion products. Here, by a simple cocatalyst engineering technique, the selective conversion of BA over Zn2In2S5 nanosheets (ZIS) is maneuvered. Two types of cocatalysts, i.e., Pt and Cd, are photo‐deposited onto ZIS that can shift the selectivity to diverse products, namely, Pt to benzaldehyde (BAD) and Cd to the carbon‐carbon (C─C) coupling compounds. Mechanistic studies indicate that Cd has a high reducing capacity to convert BAD back to the ketyl radical (C𝛼 radical), favoring the construction of the C─C bonds. Pt, however, facilitates the generation of C𝛼 radicals but is energetically unfavorable for their coupling reactions, resulting in the generation of BAD as the main product. Theoretical calculation reveals that the distinct catalytic behaviors of Pt and Cd stem from their different electronic structures that govern the adsorption strength to the reaction intermediates and the reaction energy barriers of the C─C coupling step. This work not only addresses the challenge of selectivity regulation for BA conversion but also brings fresh mechanistic insights into the role of the cocatalysts.

Optimizing Formation Energy Barrier of NiCo-LDH Cocatalyst to Enhance Photoelectrochemical Benzyl Alcohol Oxidation.

Using organic oxidation reactions to replace the oxygen evolution reaction is a promising approach for producing high-value organic products and hydrogen. Here, we report a photoelectrochemical benzyl alcohol oxidation system based on an α-Fe2O3 photoanode coated with a NiCo-layered double hydroxide (NiCo-LDH) cocatalyst. By adjustment of the relative content of Ni and Co in the NiCo-LDH, the optimized photoanode achieved a benzyl alcohol conversion efficiency of 99.1% and benzoic acid selectivity of 90.9%. Experimental studies revealed that the benzyl alcohol oxidation reaction proceeds via an indirect catalytic mechanism involving high-valence species of the NiCo-LDH cocatalyst. Co in NiCo-LDH reduced the formation energy barrier and oxidative capability of the high-valence species, thereby influencing the performance of the photoanode. This work provides insights into the crucial role of cocatalyst composition in organic reaction oxidation and contributes to developing various photoelectrochemical organic oxidation systems.

Dynamically Cyclic Fe2+/Fe3+ Active Sites as Electron and Proton-Feeding Centers Boosting CO2 Photoreduction Powered by Benzyl Alcohol Oxidation.

Solar-driven CO2 photoreduction holds promise for sustainable fuel and chemical productions, but the complex proton-coupled multi-electron transfer processes and sluggish oxidation half-reaction kinetics substantially hinder its efficiency. Here, we devised a rational catalyst design to address these challenges by fabricating ferrocene carboxylic acid-functionalized Cs3Sb2Br9 nanocrystals (CSB-Fc NCs), which facilitate simultaneous benzyl alcohol oxidation and CO2 reduction reactions under visible-light irradiation. The synchronized proton-coupled electron transfer processes between the reduction and oxidation half-reactions on CSB-Fc NCs resulted in a 5-fold increase in the CO2 reduction rate (45.56 μmol g-1 h-1, 97.9% CO selectivity) and a 5.8-fold enhancement in benzyl alcohol conversion (97.7% selectivity for benzaldehyde) compared to the CSB. Insitu Raman and ultraviolet-visible diffuse reflectance spectra revealed that the dynamic Fe2+/Fe3+ redox loop within the Fc unit serves as the actual active site, facilitating the activation of substrate molecules. More importantly, insitu attenuated total reflection Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry spectroscopy, with isotope labeling of Deuteron-benzyl alcohol and 13CO2, confirmed that proton transfer from the hydroxyl group generates reactive protons at the Fe2+/Fe3+ site, enabling efficient CO2 photoreduction through subsequent protonation steps. This work offers a cost-effective and efficient approach for synergetic CO2 photoreduction driven by organic synthesis, advancing solar energy utilization.

Light-Driven Organic Transformation with Bismuth Vanadate Photoanodes

Photoelectrocatalysis stands at the forefront of transformative advancements in the chemical industry, offering a path toward a more sustainable future. Harnessing abundant solar energy through semiconducting photoelectrodes, this approach drives redox reactions directly at the electrolyte interfaces, significantly reducing the required energy input and eliminating the need for toxic or costly homogeneous catalysts. Beyond water splitting and carbon dioxide reduction, the applicabilities of photoelectrocatalysis have been expanded to biomass upgrading and synthetic chemistry over the last ten years. In this work, we focus on the selective conversion of benzyl alcohol to benzaldehyde in acetonitrile, excluding the formation of benzoic acid, employing indirect photoelectrocatalysis with bismuth vanadate (BiVO4) as a photoanode, achieving nearly 100% Faradaic efficiency. Notably, our investigation reveals the emergence of surface states formed between BiVO4 and the redox mediator, N-hydroxy-succinimide (NHS), resulting in a gradual decline in photocurrent density over time. Small perturbation techniques, including electrochemical impedance spectroscopy and intensity-modulated photocurrent spectroscopy, were utilized for probing into the carrier dynamics at the electrolyte interface. In addition to blocking charge transfer sites of BiVO4, adsorption of NHS radicals also facilitates charge recombination on the photoelectrode surface. In addressing this issue, we present evidence that the density of these surface states can be effectively suppressed through optimized photoelectrode deposition methods as well as dopant incorporation. The roles of electrolytes and trace water impurities were also systematically analyzed. Our findings underscore the critical importance of understanding the chemical and dynamic landscapes at the semiconductor-electrolyte junction for unlocking the full potential of photoelectrocatalysis. This work sheds light on the intricacies of the photoelectrocatalytic processes and offers valuable insights for advancing the field and directing energy flow toward target molecular transformations with unique product selectivity.

One‐Step Synthesis of Melem‐Based Supramolecular Assemblies and Their Photocatalytic Properties

AbstractIn this work, melem‐based supramolecular assemblies were obtained in one step by thermal treatment of melamine in an autoclave in the presence of sodium chloride. The detailed analysis showed that the obtained powder consists of two phases: poorly crystalline Na‐PHI flakes and rod‐shaped melem hydrate single crystals (several micrometers long and ~300–500 nm wide). Melem hydrate crystals absorb light in the visible range (Eg=2.7 eV) and demonstrate photocatalytic activity in the reaction of partial oxidation of benzyl alcohol to benzaldehyde by air under visible light with high selectivity for the target product. At 60 % conversion of benzyl alcohol, the selectivity of benzaldehyde formation is above 95 %.

Unusually high selectivity (100 %) of photocatalytic C[sbnd]C coupling achieved by instant reverse reduction of byproducts

The photocatalytic CC coupling of benzyl alcohol (BA) into hydrobenzoin (HB), is appealing to obtain high-value chemicals. However, the selectivity of HB is still low due to the inevitable formation of benzaldehyde. Herein, we report In(OH)3-ZnS photocatalyst for CC coupling of BA into HB with very high selectivity (∼100 %). The introduction of In(OH)3 onto ZnS with stable interaction facilitates light harvesting and separation of photo-excited charges. As a result, BA conversion on optimized In(0.1)-ZnS catalyst (73 %) is much higher than ZnS (29 %). Besides, the surface hydroxyl groups derived from In(OH)3 enables the facile desorption of CH(OH)Ph radical. Therefore, the over oxidation of CH(OH)Ph radical into by-product of benzaldehyde can be effectively inhibited. More significantly, in-situ FTIR spectra and reduction of by-product manifest the instant reverse reduction process of benzaldehyde into CH(OH)Ph radical during CC coupling of BA, which is the key to realizing satisfied HB selectivity (100 %). Theoretical simulations reveal that the weak adsorption of CH(OH)Ph radical over catalyst and the high energy barrier of over-oxidation of CH(OH)Ph into benzaldehyde contributes to the formation of highly selective coupling products. This work will inspire new insights to design rational photoredox systems for organic transformations with high selectivity.

Urea Enzymolysis‐Induced Ions Replacing: A Promising Strategy for One‐Pot Loading of Core–Shell Heterojunction on 1D Catalyst Support

AbstractEven distribution of core–shell heterojunction on porous catalyst supports is promising to get the super‐catalysts, yet laborious preparation hinders the wide application. A novel strategy of urea enzymolysis‐induced ions replacement is proposed for one‐pot loading of Bi12O17Cl2@Bi48Al2O75 core–shell heterojunction onto porous Al2O3 nanorod (named as Al2O3‐Bi12O17Cl2@Bi48Al2O75). The clever combination of urea enzymolysis and precipitation reactions that consume the ions generated in urea enzymolysis can switch the “on‐off” of urease, and thus allow the precise controlling of the concentration and existence time of the ions, as well as ions replacement. It is the urea enzymolysis‐induced ions replacing strategy that can generate the unique structure of Al2O3‐Bi12O17Cl2@Bi48Al2O75, and it is the distinctive structure that can get the selectivity of 96% benzaldehyde with 90% benzyl alcohol (BA) conversion in the photocatalytic oxidation of BA. The ions replacement, the growth of Al2O3‐Bi12O17Cl2@Bi48Al2O75, and the photocatalytic mechanism are investigated in detail. This work highlights a novel and convenient strategy for one‐pot loading core–shell heterojunction onto porous nanorod support, unveils a fresh biosynthesis of nanomaterials with elaborate structure, and thus paves the way for wide application of elaborate nanomaterials.

Efficient and selective photocatalytic oxidation of benzylic alcohols with built-in electric field CsPbBr3/SiO2 nanocomposites through Fe3+ gradient doping

Lead halide perovskite nanocrystals (PNCs) have emerged as promising materials for photocatalysis due to their exceptional optoelectronic properties, yet achieving efficient charge separation and selective oxidation reactions remains a significant challenge. In this study, we report the synthesis of Fe3+-doped CsPbBr3/SiO2 nanocomposites (Fe-PNCs/SNPs) with gradient energy levels, designed to enhance photocatalytic performance. Our results demonstrate that Fe3+ doping introduces mid-gap states, promotes photoinduced charge separation, and generates reactive oxygen species (ROS) such as O2− and OH radicals under sunlight-simulating light irradiation from a 300 W Xe arc lamp. The Fe20-PNCs/SNPs catalyst achieved over 99 % conversion of benzyl alcohol to benzaldehyde with high selectivity and stability in the ethanol under ambient conditions. Additionally, the catalyst exhibited excellent recyclability and broad substrate tolerance. These findings highlight the innovative design of gradient energy levels in perovskite nanocomposites, offering a new strategy for enhancing photocatalytic efficiency in selective organic transformations.

0D/1D p-n heterostructured composite of bismuth ferrite perovskite clusters on sodium titanate nanotube arouse exceptional blue-light-driven photooxidation

This study describes the synthesis of a 0D/1D p-n heterostructured composite of bismuth ferrite perovskite clusters on sodium titanate nanotubes prepared using an in-situ hydrothermal method. BiFeO3/Na2Ti3O7 (BFT) nanocomposite, forming a p-n heterojunction due to the equilibrium of Fermi level, exhibits exceptional blue-light-driven photo-oxidation activity with an exceptional benzyl alcohol conversion rate of 29.64 mmolproduced BAD·g−1 h−1. The outstanding performance originates from the promotion of photogenerated charge separation and effective inhibition of charge recombination due to internal electric field of p-n heterojunction. Density functional theory calculations combined with femtosecond transient absorption spectroscopy distinctly confirms the efficient separation and transfer of photogenerated carriers to be S-scheme charge transfer mechanism over the p-n heterojunctions. Furthermore, in-situ infrared spectroscopy combined with XPS results demonstrate the strong adsorption of benzyl alcohol and weak adsorption of benzaldehyde on BFT, which facilitates the transformation of reactant and desorption of product. This study provides a simple and effective approach to enhance photocatalytic selective oxidation reactions.

Selective oxidation of benzyl alcohols photocatalyzed by asymmetric cobalt thioporphyrazine supported on alumina

The sunlight-powered transformation of alcohols to corresponding carboxylic acids offers a feasible route for fine chemical synthesis. In this work, the asymmetric cobalt tri(2,3-bis(butylthio)maleonitrile)-(1,4-dithiin) porphyrazine (CoPz(SBu)6(dtn)) was synthesized, more importantly, its single crystal was further obtained by the solvent evaporation method. Then the asymmetric CoPz(SBu)6(dtn) supported on neutral Al2O3 particles to form composite photocatalyst CoPz(SBu)6(dtn)@Al2O3, which possessed strong visible light absorption. Under simulated sunlight irradiation using a xenon lamp, the composite photocatalyst CoPz(SBu)6(dtn)@Al2O3 exhibited excellent photocatalytic activity for selective oxidation of benzyl alcohol to benzoic acid in water under conditions of green H2O2 as oxidant and K2CO3 as additive. The conversion of benzyl alcohol was up to 53.8 % together with 99 % selectivity of benzoic acid over composite photocatalyst CoPz(SBu)6(dtn)@Al2O3. Meanwhile, this photocatalytic system had feasible substrate generalizability and excellent photocatalytic activity for substituted benzyl alcohols containing both electron-donating and electron-withdrawing substituents. The composite photocatalyst CoPz(SBu)6(dtn)@Al2O3 exhibited excellent photocatalytic durability, which was confirmed by the recycling experiments. This work manifests the asymmetric thioporphyrazine as photocatalyst is feasible in implementing sunlight-powered selective transformation.

Specific Photocatalytic C-C Coupling of Benzyl Alcohol to Deoxybenzoin or Benzoin by Precise Control of Cα-H Bond Activation or O-H Bond Activation by Adjusting the Adsorption Orientation of Hydrobenzoin Intermediates.

Benzyl alcohol (BA) is a major biomass derivative and can be further converted into deoxybenzoin (DOB) and benzoin (BZ) as high-value products for industrial applications through photocatalytic C-C coupling reaction. The photocatalytic process contains two reaction steps, which are (1) the C-C coupling of BA to hydrobenzoin (HB) intermediates and (2) either dehydration of HB to DOB or dehydrogenation of HB to BZ. We found that generation of DOB or BZ is mainly determined by the activation of Cα-H or O-H bonds in HB. In this study, phase junction CdS photocatalysts and Ni/CdS photocatalysts were elaborately designed to precisely control the activation of Cα-H or O-H bonds in HB by adjusting the adsorption orientation of HB on the photocatalyst surfaces. After orienting the Cα-H groups in HB on the CdS surfaces, the Cα-H bond dissociation energy (BDE) at 1.39 eV is lower than the BDE of the O-H bond at 2.69 eV, therefore improving the selectivity of the DOB. Conversely, on Ni/CdS photocatalysts, the O-H groups in HB orient toward the photocatalyst surfaces. The BDE of the O-H bonds is 1.11 eV to form BZ, which is lower than the BDE of the Cα-H bonds to the DOB (1.33 eV), thereby enhancing the selectivity of BZ. As a result, CdS photocatalysts can achieve complete conversion of BA to 80.4% of the DOB after 9 h of visible light irradiation, while 0.3% Ni/CdS photocatalysts promote complete conversion of BA to 81.5% of BZ after only 5 h. This work provides a promising strategy in selective conversion of BA to either DOB or BZ through delicate design of photocatalysts.

In-situ ‘X’ doped ‘GCN’ photocatalyst enables selective aldehyde synthesis via photo-oxidation of benzyl alcohol under ambient conditions

Photo-oxidative selective conversion of benzyl alcohols using graphitic carbon nitride (GCN) is a sustainable strategy for conventional metal-doped heterogeneous catalytic oxidation systems. Non-metal doped graphitic carbon nitride (a subclass of GCN) enhances its properties as an efficient photocatalyst for oxidation. These heteroatom non-metal dopants alter the optical energy gap and chemical and electronic properties of GCN, making it ideal for creating cost-effective, practical utility. So, herein, we designed heteroatoms (X = B, S, C) doped GCN photocatalysts derived from melamine (M) with different heteroatom ingredients and compared their activity in detail. Among these, the photo-oxidation of benzyl alcohol under blue LED by S-doped GCN (S-GCN) photocatalyst exhibits utmost higher photocatalytic activity than other heteroatoms doped GCN photocatalyst due to suitable band gap and slow photoinduced charge carriers recombination. The suitable energy gap with higher chemical stability is accountable for the substantial increase in the photocatalytic efficiency of S-GCN in the solar light responsive integrating reactions of oxidation of benzyl alcohol in aerobic conditions. Attaining an exceptional >99 % selectivity towards benzaldehyde (up to 5 cycles without significant loss of activity) marks a remarkable milestone. This opens up new possibilities for using these simple non-metal-doped photocatalysts in fine chemical synthesis.

Novel synthesis of vanadium phosphorus/ cerium promoted manganese oxide (VPO/Ce-OMS-2) nanocomposite as an efficient and selective catalyst for the aerobic oxidative coupling of benzyl alcohol and aniline to imine in the liquid phase

In this investigation, the VPO/Ce-OMS-2 composite was synthesized via the mechanochemical method and it was employed for the synthesis of imine in the liquid phase through a two-step process of oxidation of benzyl alcohol and subsequent condensation with aniline using air as an oxidant. The composite was synthesized with different mass ratios of (1:1), (1.5:1), (2:1) and (2.5:1). The effect of the VPO/Ce-OMS-2 mass ratio on catalyst activity has been investigated. As the mass ratio increases from (1:1) to (2:1), the benzyl alcohol conversion gradually increases, reaching 93% at a (2:1) mass ratio. Among the synthesized samples, the VPO/Ce-OMS-2(2:1) composite exhibited the highest selectivity towards imine formation and conversion of benzyl alcohol. Various techniques, such as XRD, FT-IR, BET, FESEM, EDX, DRS, NH3-TPD, and HRTEM, were utilized to characterize the catalysts. Results indicated that the composite synthesized with a (2:1) mass ratio has a favorable surface area, a mixture of micro-meso structures, and a high number of acidic sites, as confirmed by BET-BJH and NH3-TPD techniques. The DRS analysis demonstrated that the interaction between the two catalysts, VPO and Ce-OMS-2, enhances the selectivity for the desired product. The results clearly show the synergism effect in the combination of components VPO and Ce-OMS-2 and improving the activity and selectivity of the synthesized nanocomposite. The effects of reaction temperature, reaction time, solvents, VPO/Ce-OMS-2 mass ratio, catalyst amount, and reusability were studied. Recycling results for the VPO/Ce-OMS-2(2:1) composite show that the benzyl alcohol conversion decreases slightly after five cycles of use, and its stability is almost maintained. Optimizing the reaction conditions (0.2 g catalyst, VPO/Ce-OMS-2 mass ratio (2:1), solvent toluene, reaction temperature 90°C, and t = 8 h) resulted in a 93% conversion of benzyl alcohol with complete selectivity for the imine.

Gold supported on Bi2MoO6 based on oxygen vacancy structure: Enhanced adsorption activation for efficient photocatalytic selective oxidation of benzyl alcohol

In this work, ethylene glycol was used as a mild reducing agent to prepare Bi2MoO6 support with oxygen vacancies. By introducing Au active species, an Au/BMO-Ov (Bi2MoO6 support with oxygen vacancies) photocatalyst was synthesized, which was co-modified with oxygen vacancies and Au NPs (nanoparticles), and significantly improved the capability of Bi2MoO6 for visible light-driven BA (benzyl alcohol) conversion. The 1 wt% Au/BMO-Ov exhibited the highest conversion (98.8 %) of BA and excellent selectivity (97.4 %) of BAD (benzaldehyde) under visible light. Oxygen vacancies have an inhibitory effect on the recombination of photogenerated carriers. Au NPs acted as both photosensitizers (LSPR effect captures light and generates electrons and holes) and active species (used as Lewis acids). The results of photoelectrochemistry (PEC) tests confirmed that the synergistic interaction of Au and oxygen vacancies enhanced the photoactivity of bismuth molybdate. Meanwhile, density functional theory (DFT) calculations indicated that oxygen vacancies and Au synergistically reduced the bandgap energy of Bi2MoO6 and enhanced the adsorption of BA. Au served as the Lewis acid site for adsorption of BA, and improved the reactivity of light-driven BA conversion. The corresponding mechanism was proposed based on the experimental results and DFT calculations.

Intensified O2 activation and lattice O supply at inverse oxide-metal interface for catalytic oxidation reactions: A case study in alcohol oxidation

Inverse oxide/metal catalysts are recently employed and of great importance in catalytic oxidation reactions, due to the high activity and sintering-resistance. However, the investigations for identification of active-site structure, adsorption-activation of O2, and insight into interface-enhanced mechanism are relatively scare. Herein, the inverse “CoOx-Au” ensemble (∼10 nm CoOx nanoparticles onto ∼30 nm Au particles) for gas-phase alcohol oxidation was exampled to investigate above issues, under the premise of delivering 92 % benzyl alcohol conversion with 98 % benzaldehyde selectivity at 240 °C and atmospheric pressure. It is revealed that O2 is activated at CoOx-Au interface. The “CoO-Au ↔ Co3O4-Au” redox cycle at CoOx-Au interface proceeds over the “CoO↔Co3O4” cycle on CoOx surface, due to the weakened interfacial Co-O bond. And the enhanced redox cycle intensifies O2 activation and lattice O supply. The O2 activation at inverse oxide-metal interface provides promising clue for rational design of inverse catalysts for catalytic oxidation reactions.

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.

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.

La(FeCuMnMgTi)O3 High-Entropy Oxide Nanoparticles as Highly Efficient Catalysts for Solvent-Free Aerobic Oxidation of Benzyl Alcohol.

In this work, a solid-state method for the synthesis of perovskite La(FeCuMnMgTi)O3 high-entropy oxide (HEO) nanoparticles is detailed. Additionally, the high performance of these nanoparticles as catalysts in the aerobic and solvent-free oxidation of benzyl alcohol is demonstrated. The structural features of HEO nanoparticles are studied by X-ray diffraction and high-resolution transmission electron microscopy. The La(FeCuMnMgTi)O3 nanoparticles demonstrate excellent benzyl alcohol conversion rates and selectivity for benzaldehyde, reaching 10.6% conversion and 52.8% selectivity after reaction for only 4 h and ≤75.6% conversion after 24 h. In addition, the as-prepared HEO catalyst displays robust stability in benzyl alcohol oxidation. Density functional theory calculations demonstrate that the adsorption energy of benzaldehyde on the HEO surface is lower than that of the benzoic acid. This, in turn, hinders the gradual conversion of benzaldehyde to benzoic acid on the surface of HEO and retains benzaldehyde as the main product.

Kinetic Studies on Ruthenium(III) Chloride‐Catalyzed Oxidation of Benzyl and Homobenzyl Alcohols Using Cerium(IV) Sulfate under Acidic Medium

AbstractThis study investigates the kinetics of oxidative conversion of benzyl and homobenzyl alcohols to carbonyls using cerium(IV) sulfate in the presence of ruthenium(III) complex under mild acidic conditions. The results revealed that the low concentration of both alcohols and cerium(IV) ions drives the reaction to a first‐order kinetics, whereas a higher concentration induces zero‐order kinetics. In addition, the kinetics of the reaction were altered by the additives of hydrogen ions, cerium(III) ions, and chloride ions. We hope this study will be helpful in understanding the reaction kinetics of the oxidation of primary alcohols.