Selective Oxidation Of Benzyl Alcohol Research Articles

Dual-functional reaction strategy boosts carbon dioxide reduction by coupling with selective benzyl alcohol oxidation on nano-Au/BiOCl photocatalysts

Photocatalytic CO2 reduction without using sacrificial agents remains a big challenge. Herein, we report a dual-functional reaction on the Au-decorated 3-dimensional BiOCl nano-photocatalyst (Au/3D-BOC) that couples photocatalytic CO2 reduction with benzyl alcohol (BA) oxidation. On the optimized 1.0% Au/3D-BOC photocatalyst, the CO production rate reached 0.17 µmol cm-2 h−1 under AM 1.5 solar simulator light source, and the BA conversion was 48.04% with benzaldehyde (BAD) selectivity above 99%. The density functional theory (DFT) calculations demonstrate the decrease of the reaction thermodynamic energy barriers after loading Au. And various characterizations reveal the dependence of the interaction between Au NPs and 3D-BOC on Au loading, which is essential to separating photogenerated carriers and prolonging their lifetime. On this basis, the reaction pathways of CO2 photoreduction and selective BA oxidation over Au/3D-BOC were proposed. This work provides a new approach to promoting CO2 reduction and BA oxidation with high economic benefits.

Poly(dibenzothiophene-S,S-dioxide)-Fe2O3 heterojunction for photocatalytic hydrogen production coupled with selective oxidation of benzyl alcohol

Photocatalytic conversion of benzyl alcohol (BA) into value-added fine chemicals and hydrogen (H2) in water medium provides a novel strategy for green synthesis. The construction of Z-scheme heterostructures not only realize enhanced charge-separation efficiency, but also remain strong drive force for photocatalytic reaction, which exhibit great potentials toward simultaneously generating benzaldehyde (BAD) and H2. Herein, we report a noble-metal-free Z-scheme photocatalytic system consisting poly(dibenzothiophene-S,S-dioxide) (PSO) and α-Fe2O3 for selective oxidation of BA with synchronous H2 production. Such nanocomposites can effectively transfer and reduce the recombination of photoexcited charge carriers, therefore maintaining the oxidizability of holes of α-Fe2O3 and the reducibility of electrons of PSO. As expected, PSO-Fe2O3 with a mass of ∼5 mg under optimal composition ratio exhibited an impressive photocatalytic activity with BAD and H2 yields up to 23.1 and 29.5 μmol h−1, respectively, which is among the top photocatalytic performance reported so far for selective photocatalytic oxidation of BA in the aqueous solution.

Se and P dual doped carbon for highly selective oxidation of benzyl alcohol

Metal-free heterogeneous oxidation of alcohols to corresponding aldehydes is a typical green selective oxidation reaction. Rational designing of the metal-free catalyst is highly desired. In the present work, P and Se dual doped carbon catalyst was prepared to achieve a high catalytic efficiency for the selective oxidation of benzyl alcohols to benzaldehyde. The doped P and Se exhibited a synergistic effect for enhancing the titled catalytic performance. The doped P can donate electrons to the adjacent atoms while the doped Se can accept electrons from the adjacent atoms. These interactions accelerated the electron transfer on the carbon surface and consequently enhanced the catalytic activity. Kinetic study revealed that the selectivity was kinetically improved by the doped heteroatoms. The oxidation mechanism investigation indicated that both radical and nonradical routes were involved in the titled reaction. In addition, the dual doped carbon catalyst also showed a good catalytic performance for the various benzyl alcohol derivatives. These finding suggest that the dual doped atoms are promising strategy to improve the catalytic activity and selectivity of the carbon-based metal-free catalysts for the aerobic selective oxidation reactions.

Photochemical Selective Oxidation of Benzyl Alcohols to Aldehydes or Ketones.

Using Eosin Y as a metal-free photocatalyst and O2 as an oxidant, the present study reports a new photochemical protocol that enables efficient aerobic oxidation of various benzyl alcohols to the corresponding aldehydes or ketones in excellent yields under mild reaction conditions. The catalyst system presents good functional-group tolerance and exquisite chemoselectivity, which also can easily be scaled-up to gram scale. Moreover, the methodological applications in practical synthesis of several organic molecules and the primary reaction mechanism were also discussed.

Solvent-free selective oxidation of benzyl alcohol using Ru loaded ceria-zirconia catalysts

Selective oxidation of alcohols to aldehydes or ketones is a fundamental process in organic chemistry and the development of green and sustainable transformations are strongly required. Herein, we focused on the development of Ru-based catalysts deposited over ceria-zirconia supports (CZRu) for the solvent free oxidation of benzyl alcohol using air as oxidant, which is a cheap and safe process and meets to the atom economy and environment requirements. XPS characterization of the material reveals that the formation of RuO2 on the surface is necessary to achieve higher catalytic activity. The activity is strongly related to the reducibility of the material and to the close interaction between ceria-zirconia and RuO2, with the likely formation of Ru-O-Ce arrangements. The greater mobility of oxygen due to the formation of bridging oxygens in Ru-O-Ce and to the formation of superoxide species (O2−) over Ce3+ sites, significantly boosts the selective oxidation of alcohols. CZRu is a promising material with a remarkable 61% alcohol conversion at 90 °C without solvents; it also exhibits high activity (55% conversion) and complete selectivity (100%) for the selective oxidation of 1-phenylethanol to acetophenone. Overall, the formulation is among the most active reported so far under solvent free conditions and molecular oxygen. In addition, the reaction over CZRu exhibits an environmental factor (E-factor) lower than 1 (0.95) confirming the sustainability of the proposed process.

Constructing a Photocatalyst for Selective Oxidation of Benzyl Alcohol to Benzaldehyde by Photo-Fenton-like Catalysis.

A photoactive metal-organic framework (MOF), [K(H2O)][Cu(DPNDI)][Cu(DPNDI)(CH3CN)(H2O)] [Cu1.5(DPNDI)1.5H1.5P2W18O62]·2H2O (Cu(Ι)W-DPNDI), was prepared by combining a functional photosensitizer N, N'-bis(4-pyridylmethyl)naphthalene diimide (DPNDI), copper(I) ions, and an oxidation catalyst [P2W18O62]6- into a single framework via a hydrothermal process. Cu(Ι)W-DPNDI exhibited a stable structure, strong light absorption capacity, a suitable band gap, and photoelectric properties, which provided favorable conditions for photocatalysis. In the confined space, the well-aligned Cu(I) ions and POM polyanions played a synergetic effect in the electron-transfer process and reactive oxygen species generation. By coupling photocatalysis and heterogeneous Fenton-like catalysis, Cu(Ι)W-DPNDI displayed high efficiency for the selective oxidation of aromatic alcohols, with up to >99% selectivity and 75% yield.

MIL-53(Fe)@perylene Diimide All-Organic Heterojunctions for the Enhanced Photocatalytic Removal of Pollutants and Selective Oxidation of Benzyl Alcohol

Organic semiconductors are promising materials for the photocatalytic treatment of pollutants and organic synthesis. Herein, MIL-53(Fe)@perylene diimide (PDI) organic heterojunctions were constructed by ultrasonic assembly using PDI as the co-catalyst, and PDI organic supramolecular material was uniformly distributed on the surfaces of MIL-53(Fe). The most effective M53@PDI-20 organic heterojunctions achieved 72.7% photodegradation of rhodamine B (10 mg/L) within 50 min and a 99.9% reduction in Cr(VI) (10 mg/L) for 150 min, and the corresponding apparent degradation rate constants were higher than a single component. Meanwhile, the conversion rate of benzyl alcohol over M53@PDI-20 achieved 91.5% for 5 h with a selectivity of above 90% under visible light exposure, which was more than double that of PDI. The well-matched band structures and the strong π–π bonding interactions between MIL-53(Fe) and PDI can increase the electron delocalization effect to facilitate the transfer and separation of photogenerated carriers. Lots of oxidative reactive species (h+, •O2− and •OH) also played a great contribution to the strong oxidation capacity over the heterojunctions system. This work suggests that MIL-53(Fe)@PDI organic heterojunctions may be a promising material for pollutant removal and organic synthesis.

Guanine-derived nitrogen-doped carbon nanosheets for selective oxidation of benzyl alcohol

Guanine-derived nitrogen-doped carbon nanosheets for selective oxidation of benzyl alcohol

Revealing the Crystal Facet Effect of Ceria in Pd/CeO2 Catalysts toward the Selective Oxidation of Benzyl Alcohol

Revealing the Crystal Facet Effect of Ceria in Pd/CeO₂ Catalysts toward the Selective Oxidation of Benzyl Alcohol

Differences in the Oxidizing Species on the Surface of Metal-Doped Ferrihydrite and Hematite in the Alkaline S(IV)-O2 Solution

Although inorganic Fe(IV)═O oxo and Fe(III)-OOH peroxo have attracted more attention in aqueous environments, direct evidence for the characterization and identification of those oxidizing species is still lacking. In this study, the doped Cu/Co increases the reactivity of ferrihydrite/hematite in oxidizing As(III) by S(IV)-O2 under alkaline and dark conditions. Quenching experiments exclude the contributions of ·OH, O2•–, SO3•–, SO4•–, SO5•–, HSO5–, and H2O2 and confirm that peroxo and oxo are primary oxidizing species in As(III) oxidation. Electrochemical analyses indicate that Fe(IV)═O oxo and Fe(III)-OOH peroxo are primarily located on the surface of ferrihydrite and hematite. Selective oxidation of methyl phenyl sulfoxide and methyl phenyl sulfide to the corresponding oxidation products further reveals the presence of ≡Fe(IV)═O oxo on both ferrihydrite and hematite, and the doped Cu/Co significantly decreases the produced ≡Fe(IV)═O oxo on ferrihydrite, while increases the produced ≡Fe(IV)═O oxo on hematite. Meanwhile, selective oxidation of benzyl alcohol to benzaldehyde indicates the presence of ≡Fe(III)-OOH peroxo on both ferrihydrite and hematite, and the doped Cu/Co apparently increases the produced ≡Fe(III)-OOH peroxo on ferrihydrite and hematite. Raman analysis further reveals the presence of ≡Fe(IV)═O oxo and ≡Fe(III)-OOH peroxo on pure and metal-doped ferrihydrite/hematite, which also confirms that the doped Cu/Co decreases the produced ≡Fe(IV)═O oxo on ferrihydrite and increases ≡Fe(IV)═O oxo on hematite, while apparently increasing ≡Fe(III)-OOH peroxo on both ferrihydrite and hematite. This study enriches our understanding on the oxidizing species in the S(IV)-mediated oxidation processes under alkaline conditions, providing new insight on the oxidation reactivity of surface peroxo and oxo species mediated by the doped metal ions.

Carbonyl-anchored single-atom palladium achieved on waste printing paper-derived carbon material by impregnation method: remarkable performance in selective oxidation of benzyl alcohol

N element can form various forms of coordination with metals, so it is used in the preparation of single-atom catalysts widely. However, the strong coordination bond between N and metals will inhibit the catalytic activity of the metal atoms. In this work, the waste printing paper was used to prepare a new type of carbon material by calcining at high temperature in water vapor atmosphere (PC-900). The waste printing paper-derived carbon presented the only carbonyl groups, which resulted in the loading of palladium (Pd) as single atoms (Pd/PC-900). X-ray photoelectron spectroscopy characterization and density function theory simulation proved that the Pd atom coordinated with two carbonyl groups. In the oxidation of benzyl alcohol, the adsorption energy of benzyl alcohol on Pd single atom was higher than benzaldehyde. The reaction selectivity of Pd/PC-900 to benzaldehyde was over 99.3% and the reaction rate of Pd/PC-900 (TOF = 19.9 × 103 h−1) was about twice of conventional Pd/AC (TOF = 9.7 × 103 h−1) at 140 °C in 0.1 MPa oxygen. After four runs, the activity and selectivity of Pd/PC-900 remained unchanged. Several analysis methods demonstrated that benzyl alcohol was oxidized to benzaldehyde with the alternate catalysis of Pd2+ and Pd0.

Highly Active and Recyclable CuxFe3‐xO4 NPs for Selective Oxidation of Benzyl Alcohol using TBHP as an Oxidant

AbstractHerein, we report the synthesis of CuxFe3‐xO4 nanoparticles (NPs) via a novel, facile, cost‐effective, and eco‐benign method using a water‐soluble egg‐white. The characterization studies confirmed that the fabricated CuxFe3‐xO4 NPs are crystalline and possess super‐paramagnetic behavior. The fabricated magnetic CuxFe3‐xO4 NPs also exhibited excellent catalytic performance towards the selective oxidation of benzyl alcohol to benzaldehyde using tetra‐butyl hydroperoxide (TBHP) as an oxidant under solvent‐free conditions. It was found that the addition of egg‐white during the synthesis significantly enhanced both the crystallinity and catalytic activity. Among the prepared ratios, Cu1.5Fe1.5O4 demonstrated the highest conversion (>73 %) and complete selectivity (100 %) to benzaldehyde under lenient oxidation conditions. The novelty of the work lies in achieving the magnetically recoverable CuxFe3‐xO4 NPs in the absence of any base or other organic reagents and is highly selective for the production of benzaldehyde under the mild reaction condition.

Ultrasonic irradiation-assisted MnFe2O4 nanoparticles catalyzed solvent-free selective oxidation of benzyl alcohol to benzaldehyde at room temperature.

Magnetic nanoparticles (NPs) play a vital role in heterogeneous catalysis because of their easy separation, and effective recyclability. Herein, we report the synthesis of MnFe2O4 NPs for use as catalysts in the selective oxidation of benzyl alcohol to benzaldehyde under mild conditions. The MnFe2O4 NPs have been synthesized by precipitation method followed by hydrothermal ageing at 180 °C for 4.0 h. We have investigated the effect of chitosan and carboxymethyl cellulose on the size or morphology of the formed MnFe2O4 NPs. The X-ray diffraction study confirms the formation of pure and crystalline MnFe2O4 with varying average crystallite sizes ranging from 18 to 28 nm based on the type of additive used. The electron microscopy study reveals that the additive plays a significant role in controlling the morphology of the formed MnFe2O4 NPs. These MnFe2O4 NPs exhibit superparamagnetic behaviour at room temperature and can effectively catalyze the solvent-free selective oxidation of benzyl alcohol to benzaldehyde in the presence of tert-butyl hydroperoxide at room temperature under ultrasonic irradiation. The developed protocol can be extended to various substituted benzyl alcohols having both the electron withdrawing and electron donating groups to afford moderate to excellent yield of the products. The catalyst is magnetically retrievable, highly stable, and can be reused up to the sixth run without significant loss of catalytic activity.

Selective oxidation of benzylic alcohols via synergistic bisphosphonium and cobalt catalysis.

A synergistic photocatalytic system using a bisphosphonium catalyst and a cobalt catalyst has been developed, enabling the selective oxidation of benzylic alcohols under oxidant-free and environmentally benign conditions. High efficiencies have been obtained for a variety of alcohol substrates, and exclusive selectivity for aldehyde products has been achieved across the board. Furthermore, this photocatalytic system proved to be efficient when performed under continuous-flow conditions, even using a simple and easily assembled continuous-flow setup.

Electron-rich pyrimidine rings enabling crystalline carbon nitride for high-efficiency photocatalytic hydrogen evolution coupled with benzyl alcohol selective oxidation

With electron-rich pyrimidine rings introduced, the obtained crystalline PCN is favored with rationally modulated band and electronic structures, resulting in efficient photocatalytic hydrogen evolution and benzyl alcohol selective oxidation.

Efficient oxidation of benzyl alcohol into benzaldehyde catalyzed by graphene oxide and reduced graphene oxide supported bimetallic Au-Sn catalysts.

A series of bimetallic and monometallic catalysts comprising Au and Sn nanoparticles loaded on graphene oxide (GO) and reduced graphene oxide (rGO) were prepared using three distinct techniques: two-step immobilization, co-immobilization, and immobilization. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), and Inductively-coupled plasma optical emission spectroscopy (ICP-OES) were used to characterize the chemical and physical properties of prepared Au-Sn bimetallic and Au or Sn monometallic nanocatalysts. The catalytic performance of the prepared nanocatalysts was evaluated in the selective oxidation of benzyl alcohol (BzOH) to benzaldehyde (BzH) using O2 as an oxidizing agent under moderate conditions. To obtain the optimal BzH yield, the experimental conditions and parameters, including the effects of the reaction time, temperature, pressure, and solvent type on BzOH oxidation, were optimized. Under optimal reaction conditions, bimetallic Au-Sn nanoparticles supported on GO (AuSn/GO-TS, 49.3%) produced a greater yield of BzH than the AuSn/rGO-TS catalysts (35.5%). The Au-Sn bimetallic catalysts were more active than the monometallic catalysts. AuSn/GO-TS and AuSn/rGO-TS prepared by the two-step immobilization method were more active than AuSn/GO-CoIM and AuSn/rGO-CoIM prepared by co-immobilization. In addition, the AuSn/GO-TS and AuSn/rGO-TS catalysts were easily separated from the mixture by centrifugation and reused at least four times without reducing the yield of BzH. These properties make Au-Sn bimetallic nanoparticles supported on GO and rGO particularly attractive for the environmentally friendly synthesis of benzaldehyde.

Controllable fabrication of a Cs2AgBiBr6 nanocrystal/mesoporous black TiO2 hollow sphere composite for photocatalytic benzyl alcohol oxidation

Photocatalytic selective oxidation of benzyl alcohol into benzaldehyde at normal temperature and pressure is one of the important topics in the catalysis field.

Enhanced activation of persulfate improves the selective oxidation of alcohols catalyzed by earth-abundant metal oxides embedded on porous N-doped carbon derived from chitosan

Metal clusters oxide were embedded in an N-doped carbon and used as catalysts for the activation of peroxydisulfate or peroxymonosulfate in the selective oxidation of benzyl alcohol. Quenching tests were done to investigate the reaction mechanism.

An Fe·MOF–Mo·POM hybrid material: a novel and efficient catalyst for selective benzyl alcohol oxidation to benzaldehyde

Designing and synthesis of an efficient catalyst for the selective oxidation of benzyl alcohol (BzOH) to benzaldehyde (BzCHO) is a significant method in green chemistry and catalysis.

Heteropoly ionic liquids functionalized γ-Fe2O3 NPs: synthesis, characterization, and catalytic application in selective oxidation of benzyl alcohol to benzaldehyde using H2O2 as a green oxidant

Heteropoly ionic liquids functionalized γ-Fe2O3 NPs: synthesis, characterization, and catalytic application in selective oxidation of benzyl alcohol to benzaldehyde using H2O2 as a green oxidant