Reaction Of Benzyl Alcohol Research Articles

Co(II) and Cu(II) Porphyrins Catalysed the Synthesis of Quinoline and Naphthoxazine via Dehydrogenative Reactions

: In this study, we developed a facile Co (II) and Cu (II)-porphyrin catalytic system for dehydrogenative coupling reaction of benzyl alcohol with acetophenone derivatives for quinoline synthesis and intramolecular cyclisation of Betti base for naphthoxazine synthesis. Functionalized porphyrins containing ester and quinoline ring (CoTPPBenzo(NPh)) and (CuTPPBenzo(NPh)) were synthesized and confirmed via various analytical techniques. These cobalt (II) and copper (II) porphyrins were tested for the synthesis of quinolines and naphthoxazines via a dehydrogenative coupling reaction. These cobalt and copper porphyrins showed excellent catalytic activity with broad substrate scope. Additionally, a series of controlled experiments were performed to support this work.

Impacts of Small SBA-15 Mesopores on Translation and Rotational Diffusion of Benzyl Alcohol.

Small SBA-15 pores can enhance the catalytic activity of gold catalysts in the selective oxidation of benzyl alcohol reaction. The goal of this work is to probe the impact of SBA-15 pores on the translational and rotational diffusion of the reactive species (e.g., benzyl alcohol). Herein, we demonstrate the use of nuclear magnetic resonance-based diffusion-ordered spectroscopy (DOSY) and T1 relaxation techniques to measure the translational and rotational diffusion coefficients of liquid benzyl alcohol molecules in three distinct environments: bulk, pore, and near-surface. The DOSY and T1 relaxation techniques render the routine diffusion measurements for liquid molecules confined in small pores possible. Furthermore, we measure the translational and rotational diffusion coefficients of benzyl alcohol molecules in the bulk, pore, and near-surface environments at varying temperatures. These measurements are then correlated via the Arrhenius equation to determine the activation energy associated with their translational (Et) and rotational (Er) diffusion. A higher activation energy suggests a more difficult diffusion process, while a lower activation energy implies a facile diffusion process. Our findings demonstrate that the ranking of Et follows the order of bulk (difficult) > near-surface > pore (easy), whereas the ranking of Er follows the order of pore (difficult) > bulk > near-surface (easy). This result suggests that the small SBA-15 pores can facilitate the translational diffusion but hinder the rotational diffusion of benzyl alcohol molecules.

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.

Synthesis of Au–Pd@CeO2 nanocomposite as a potential catalyst for the Buchwald–Hartwig cross-coupling and amination of benzyl alcohol reactions

Synthesis of Au–Pd@CeO2 nanocomposite as a potential catalyst for the Buchwald–Hartwig cross-coupling and amination of benzyl alcohol reactions

Kinetic implications of (hierarchical) zeolite fouling during liquid-phase aromatics upgrading

The kinetics of fouling in large pore zeolites (BEA, MOR), including those with hierarchical pore systems, were probed during the Brønsted acid catalyzed reaction of benzyl alcohol (BA) with 1,3,5-trimethylbenzene (TMB) by varying reactant driving force (i.e., [TMB]0/[BA]0; 11–119). In BEA, initial deactivation rate constants (kD,0) decreased exponentially with [TMB]0/[BA]0, highlighting the significance of oxygenates as deactivation precursors. Further, seeding pores with oxygenates completely suppressed measured rates in parent MOR and BEA, while seeding with TMB had no effect. Comparisons of mass accumulations of different organics (low molecular weight reaction species and coke) as functions of ln([TMB]0/[BA]0) revealed that coke (derived from oxygenate-seeded polyalkylation of TMB) disproportionately controlled deactivation rates by damping apparent (diffusion-controlled) and intrinsic (diffusion-corrected) rate constants through proton losses and/or altered molecule confinement within shrinking pores. These kinetic consequences were delayed upon introduction of mesopores, demonstrating how zeolite porosity impacts coke proliferation and behavior in liquid-phase reactions.

Ethanol Foams Stabilized by Isobutyl-Based POSS-Organosilica Dual-Particle Assemblies.

Nonaqueous foams in low-surface tension solvents (<25 mN·m-1) are highly desired for applications in fire extinguishers and detoxification gels. However, their formation is a Holy Grail of the chemical industry due to the need for stabilizers with low surface energy and high recyclability. Herein, we disclose a new strategy to generate abundant foams in ethanol and a variety of low-surface tension solvents relying on the interfacial coadsorption of two different particles. The particles consist of surface-active fluorinated silica particles, used as a stabilizer, and a novel amphiphilic polyhedral oligomeric silsesquioxane (POSS) decorated with isobutyl cage substituents, used as a frother. The interaction between POSS and fluorinated particles at the ethanol-air interface was thoroughly investigated by combining physicochemical methods (contact angle, dynamic surface tension, and dynamic light scattering methods) and catalytic tests using the model aerobic oxidation reaction of benzyl alcohol. Both particles could be conveniently recycled for at least 5 consecutive runs with high foamability and catalytic activity.

Carbon Quantum Dots/Cu2O Photocatalyst for Room Temperature Selective Oxidation of Benzyl Alcohol.

The luminescence properties and excellent carrier transfer ability of carbon quantum dots (CQDs) have attracted much attention in the field of photocatalysis. In this work, we loaded the CQDs on the surface of Cu2O to enhance the visible-light property of Cu2O. Furthermore, the composite was used for selective oxidation of benzyl alcohol to benzaldehyde. The composite catalyst achieved high selectivity (90%) for benzaldehyde at room temperature, leveraging its visible-light-induced electron transfer properties and its photocatalytic activity for hydrogen peroxide decomposition. ·OH was shown to be the main reactive oxygen species in the selective oxidation reaction of benzyl alcohol. The formation of heterostructures of CQDs/Cu2O promoted charge carrier separation and provided a fast channel for photoinduced electron transfer. This novel material exhibited enhanced levels of activity and stability for selective oxidation of benzyl alcohol. Potential applications of carbon quantum dot composites in conventional alcohol oxidation reactions are shown.

Photocatalytic C–C coupling reactions of benzyl alcohol for obtaining hydrobenzoin over Z-scheme ZnS/ZnIn2S4

The Z-scheme ZnS/ZnIn2S4 heterojunctions with sulphur vacancies were constructed for photocatalytic redox system to selectively oxidative coupling of benzyl alcohol into valuable hydrobenzoin.

Selective photocatalytic C-C coupling of benzyl alcohol into hydrobenzoin using Pt-deposited CdS nanosheets passivated with cysteamine.

Achieving high selectivity towards hydrobenzoin (HB) from photocatalytic carbon-carbon (C-C) coupling reaction of benzyl alcohol (BzOH) remains a challenge due to side competing reactions and subsequent conversions of HB into its derivatives. In this study, we have developed a high-performance CdS-based photocatalyst for synthesizing HB with precisely controlled surface properties and structure, achieving high selectivity for HB synthesis. We employed strategies such as cysteamine passivation and Pt deposition to address issues related to photogenerated charge trapping and recombination, thereby enhancing the photocatalytic capability of CdS. With optimized Pt/CdS NSs as the photocatalyst, we investigated the impact of the Pt/CdS heterostructure on intermediate reactions, which in turn altered product selectivity. Specifically, excessive Pt suppresses the electron-induced benzaldehyde-to-intermediate reaction by consuming electrons for the competing hydrogen evolution reaction (HER), leading to high selectivity toward benzaldehyde. In contrast, bare CdS without Pt suffers from insufficient charge supply for BzOH conversion due to the charge recombination issue, which promotes the subsequent conversion of HB to its derivatives. Notably, when Pt is precisely loaded to avoid dominant HER competition, the overall reaction rate increases, maintaining high selectivity towards HB and ensuring faster conversion of BzOH to HB rather than subsequent conversions of HB into its derivatives, thereby maximizing the HB yield. Subsequently, we have developed a photocatalyst that achieves a 93.4% conversion of 0.24 mmol BzOH with 85.3% selectivity toward HB under solar simulator irradiation (AM 1.5G). This work is expected to offer instructive guidance on rationally designing the photocatalyst for efficient C-C coupling reactions.

Performance scrutiny of spent lithium-ion batteries cathode material as a catalyst for oxidation of benzyl alcohol

The widespread use of Li-ion batteries (LIBs) in energy storage devices has resulted in the generation of additional waste which contains valuable metal ions and these metal ions are well known for their catalytic activities. The recovered black mass of cathode material was exposed to pretreatment with final calcination for 2 h at 800 0C. After the calcination, the material was subjected to structural characterization (XRD, FE-SEM, EDAX, and XPS). In the present work, we have used spent LIBs cathode material as a catalyst for the oxidation reaction of benzyl alcohol to benzoic acid. The catalytic activity of this recovered cathode material was found to be highly efficient showing 100% conversion of benzyl alcohol with >99% selectivity of benzoic acid with lower catalyst loading of even 2%.

Propylamine Silica-Titania Hybrid Material Modified with Ni(II) as the Catalyst for Benzyl Alcohol to Benzaldehyde Conversion

SiO2-TiO2@propylamine-Ni(II) as the catalyst for the benzyl alcohol oxidation has been synthesized by utilizing rice husk ash as the SiO2 source. This research was started by extracting SiO2 from rice husk ash and continued by synthesizing the SiO2-TiO2 composite using titanium(IV) tetraisopropoxide (TTIP) as TiO2 precursor and PEG-40 as template. The composite functionalization and metal modification were carried out by adding (3-aminopropyl)triethoxysilane (APTES) as the source of propylamine linker and impregnating NiCl2·6H2O as the nickel precursor, respectively. The catalysts were synthesized by varying the ratios between each component within the material. The prepared materials were then characterized using ATR-IR, XRD, XRF, PSA, SAA, AAS, SEM-EDX, HR-TEM, and TGA. The catalyst activity was investigated by applying it to the oxidation reaction of benzyl alcohol to benzaldehyde with H2O2 as the oxidizing agent under sonication system. The obtained products were then analyzed by using GC-MS to quantify the success of the reaction. All characterizations performed in this research generally indicate the success in the synthesis of SiO2-TiO2@propylamine-Ni(II) materials. Under the same condition including at room temperature, 1 h reaction time, and sonication system, the optimal oxidation reaction of benzyl alcohol was reached when SiO2-TiO2@propylamine-Ni(II)5 was used as the catalyst in 98.52% yield.

Co-Schiff base complexes functionalized on graphene as efficient heterogeneous nanocatalysts for alcohols oxidation

Different Schiff base complexes were prepared by immobilizing three aldehydes (4-Hydroxybenzaldehyde, 2-hydroxybenzaldehyde, and 2-Pyridinecarboxaldehyde) on graphene oxide and were fully characterized using multiple techniques such as FTIR, XRD, TGA, BET, SEM-EDS, and TEM. Then efficient heterogeneous catalysts were checked out in the selective catalytic oxidation of benzylic alcohols. The effects of different parameters, such as reaction time and temperature, were examined to obtain optimum reaction conditions. The solvent-free oxidation reaction of benzylic alcohols showed a conversion above 70% and selectivity higher than 95% in the presence of cobalt (II) Schiff base catalysts using H2O2 as an oxidant after 40 min of reaction. The reusability experiment results specified that the prepared catalysts could maintain high catalytic activity in the oxidation of benzylic alcohols (>80%) and selectivity (>96%) even after being used for three cycles.

A DFT investigation of the catalytic oxidation of benzyl alcohol using graphene oxide.

Metal-free heterogeneous materials have attracted great interest due to their potential to facilitate various organic transformations in line with circular economy and green chemistry principles. Among various 2D materials, graphene oxide (GO) is considered an attractive material for numerous applications in physics, chemistry, biology, material sciences, and catalysis. Furthermore, graphene-based catalysts exhibit good catalytic activity toward the selective oxidation of benzyl alcohol to benzaldehyde or benzoic acid under eco-friendly conditions. In this regard, a theoretical investigation was carried out to study both catalytic oxidation reaction pathways (i.e., benzyl alcohols to aldehyde and to benzoic acid) using GO as an eco-friendly and metal-free catalyst. In this study, we report a theoretical investigation at the B3LYP/6-31G level to better understand the oxidation of benzyl alcohol using GO as a metal-free catalyst. The possible bond formation was investigated using the global and local reactivity indexes derived from Fukui functions. Furthermore, we performed a non-covalent interaction (NCI) analysis to unveil the stability and the interaction nature between both reagents and GO surface. The effect of the solvent on the oxidation efficiency was also performed and the results indicate that the solvent significantly affects the decrease of reactivity by increasing the activation barriers through oxidation reactions of benzyl alcohol. Additionally, the electron localization function (ELF) analysis was performed for all intermediates showing the ionic nature of the studied epoxide structure of GO and rules out any type of covalent interaction during the oxidation reaction of benzyl alcohol. All these obtained results are in good agreement with experimental observations and reveal that the epoxide functions on the graphene surface promote an excellent catalyst turnover.

Facile synthetic route of TiO2–ZnO heteronanostructure coated by oxovanadium (IV) bis-Schiff base complex as a potential effective homogeneous/heterogeneous catalysts for alcohols redox systems

Oxovanadium (IV) bis-Schiff base complex was synthesized by a facile complexation of 2 molar ratio of 2‑hydroxy-Schiff base ligand (HL) with 1 molar ratio of VO2+ ion giving mononuclear VOL2 complex with a square pyramidal geometry. The structure conformation of HL and its corresponding VOL2 complex was assigned within various spectroscopic tools (IR, UV–vis. Mass spectra), as well as the elemental analyses (EA). The deprotonated 4-OH group in VOL2 caused a successful coating of VOL2 on a mixed oxides of TiO2–ZnO nanoparticles awarding nanocomposite of TiO2–ZnO@VOL2. By applying alternative analytical techniques, the surface morphology and internal structure TiO2–ZnO@VOL2 nanocomposites were investigated compared to that of TiO2–ZnO, i.e. by XRD, FESEM, HR-TEM, EDS and IR spectra), and also with TGA and BET (adsorption–desorption isotherm).The catalytic effectiveness of both homogeneous and heterogeneous catalysts (VOL2 and TiO2–ZnO@VOL2) was examined in the productive oxygenation reactions of BA (benzyl alcohol) by an aqueous hydrogen peroxide under an aerobic environment to the chemo-selective product benzaldehyde (BZ), and benzoic acid (BO), as the overodixation product. Both VOL2 and TiO2-ZnO@VOL2 catalysts exhibited obvious classified action by 89% and 91% yielding amount of benzaldehyde after 4 h for reaction temperature 80 and 90 °C, respectively. The differentiation between them in the catalytic reactivity was depending on the heterogeneity and the effect of the coated TiO2–ZnO nanoparticles on the VOL2 catalytic potential. The kinetic parameter of the productive redox protocols for both catalyst was examined. Additionally, some other cyclic and acyclic alcohols were exhibited the productive redox protocol in the optimum control of both catalysts.

Molybdenum oxides catalyzed the N,N‐dimethylamination of alcohols with N,N‐dimethylformamide for direct synthesis of tertiary amines

Molybdenum oxides (MoO3 − x, x = 1, 2, and 3) with three types of morphologies were prepared and applied to the reaction of benzyl alcohol with dimethylformamide (DMF) for synthesis of tertiary amines. The MoO3 − 1 catalyst prepared by direct calcination exhibited high activity and tertiary amines selectivity in the N,N-dimethylamination of benzyl alcohol under the reaction conditions at 150°C for 12 h using DMF as a methylating agent and solvent, as compared to MoO3 − 2 and MoO3 − 3 catalysts. This feature was ascribed to the high proportion of surface chemisorbed oxygen for MoO3 − 1 sample, which can promote the adsorbed benzyl alcohol transformation into benzaldehyde. The MoO3 − 1 catalyst was also found to be reusable in five consecutive runs without a significant decrease in catalytic activity. In addition, control experiments showed two parallel reaction routes in this catalytic system. One route is the reaction of benzaldehyde intermediate and DMF to form tertiary amines (Route I); the other route is that benzyl formate intermediate reacted with DMF (Route II), which has not been reported before and specifically involves the esterification of benzyl alcohol with formic acid from DMF decomposition to form benzyl formate.

Oxovanadium(V)‐Catalyzed Deoxygenative Coupling Reaction of Alcohols with Trimethylsilyl Enol Ethers in the Presence of MS3A

AbstractOxovanadium(V)‐catalyzed deoxygenative coupling reaction of allyl alcohols with trimethylsilyl enol ethers was demonstrated to afford γ,δ‐unsaturated carbonyl compounds in one‐step. The catalytic deoxygenative coupling reaction of allyl alcohols proceeded smoothly with both aromatic and aliphatic trimethylsilyl enol ethers. This catalytic deoxygenative coupling system could be applied to the deoxygenative coupling reaction of benzyl alcohols with trimethylsilyl enol ethers, providing the corresponding carbonyl compounds. Furthermore, a gram‐scale catalytic synthesis of the γ,δ‐unsaturated carbonyl compound was successfully performed to validate the scalability of this catalytic deoxygenative coupling reaction.

Transition metal-containing MgFe ex-LDH mixed oxides, effective catalysts in the hydrodeoxygenation of benzyl alcohol

Several M-MgFe-LDH precursors were prepared via co-precipitation and then calcined at 500 °C to yield the corresponding M-MgFeO mixed oxide catalysts, which were tested in the hydrodeoxygenation (HDO) of benzyl alcohol. The prepared LDH contained Mg and Fe in a mol ratio of 3:1 and 10 at% M with respect to cations, where M = Ni, Co, Ag and Cu. The Cu-MgFeO mixed oxide gave the best results, therefore we proceeded with the preparation of a Cu(x)-MgFeO series, where x = 2.5–20 at% Cu. The prepared solids were characterized by powder X-ray diffraction, nitrogen adsorption-desorption, temperature-programmed reduction with H2, temperature-programmed desorption of CO2 and energy dispersive X-ray spectroscopy. We studied the influence of the nature of the transition metal M on the activity and selectivity of the catalysts and, for the Cu-containing samples, the influence of Cu loading, reaction time and reaction temperature on their performance in the HDO reaction of benzyl alcohol. With 93.8% conversion and 93.8% selectivity towards toluene at 230 °C, 3 h reaction time and under a hydrogen pressure of 5 atm, the Cu(10)-MgFeO catalyst proved to have the best performance in the studied reaction. Therefore, its stability and reusability were checked. We also proposed a sequence of reactions for the entire HDO process, based on a reverse Mars-van Krevelen mechanism driven by oxygen vacancies formed on the catalyst surface.

Role of ancillary ligands in selectivity towards acceptorless dehydrogenation versus dehydrogenative coupling of alcohols and amines catalyzed by cationic ruthenium(II)-CNC pincer complexes.

An unexpected reversal in catalytic activity for acceptorless dehydrogenative coupling compared to acceptorless alcohol dehydrogenation has been observed using a series of cationic Ru(II)-CNC pincer complexes with different ancillary ligands. In continuation of our study of cationic Ru(II)-CNC pincer complexes 1a-6a, new complexes with bulky N-wingtips [Ru(CNCiPr)(CO)(PPh3)Br]PF6 (1b), [Ru(CNCCy)(CO)(PPh3)Cl]PF6 (1c), [Ru(CNCCy)(CO)(PPh3)H]PF6 (2c), [Ru(CNCiPr)(PPh3)2Cl]PF6 (3b), [Ru(CNCCy)(PPh3)2Cl]PF6 (3c), [Ru(CNCiPr)(PPh3)2H]PF6 (4b), [Ru(CNCCy)(PPh3)2H]PF6 (4c), [Ru(CNCiPr)(DMSO)2Cl]PF6 (6b), and [Ru(CNCCy)(DMSO)2Cl]PF6 (6c) [CNCR = 2,6-bis(1-alkylimidazol-2-ylidene)-pyridine] have been synthesized and the catalytic activities of the new complexes have been compared with their N-methyl analogues for transfer hydrogenation of cyclohexanone and acceptorless dehydrogenation of benzyl alcohol. Furthermore, all complexes have been utilized as catalysts in the dehydrogenative coupling reaction of benzyl alcohol with amines. While the catalytic activities of the new complexes for transfer hydrogenation and acceptorless alcohol dehydrogenation were found to be in line with the previously observed trend based on the ancillary ligands (CO > COD > DMSO > PPh3), for the acceptorless dehydrogenative coupling reaction, complexes containing PPh3 and DMSO ligands performed better compared to complexes containing CO and COD ligands. Based on NMR and mass investigation of catalytic reactions, a plausible mechanism has been suggested to explain the difference in catalytic activity and its reversal during the dehydrogenative coupling reaction. Furthermore, the substrate scope for the dehydrogenative coupling reaction of benzyl alcohol with a wide range of amines has been explored, including synthesizing some pharmaceutically important imines. All new complexes have been characterized by various spectroscopic techniques, and the structures of 4b and 6b have been confirmed by the single-crystal X-ray diffraction technique.

Construction of polyoxometalate-based metal−organic frameworks through covalent bonds for enhanced visible light-driven coupling of alcohols with amines

Broad spectral response and rapid carrier transport are essential in making efficient photocatalysts. In this work, we utilized Keggin-type polyoxometalates (POMs) [CoIIW12O40]6– as metal-to-metal charge transfer (MMCT) chromophores and assembled them into metal–organic frameworks (MOFs) to construct visible-light-responsive, noble metal-free crystalline POM-based MOFs (POMOFs) (CoW-1 and CoW-2). The precise introduction of MMCT chromophores extending the light absorption of POMOFs to the visible region and improving the solar energy utilization efficiency, meanwhile, the Cu-O-W covalent bonds constructed in CoW-1 makes the framework structure more robust, reduces the interfacial contact resistance, facilitates the electron transfer, suppresses the recombination of the electron-hole pairs, improves the charge carriers separation efficiency, and boosts the quantum efficiency, thus achieving high catalytic activity in the coupling reaction of benzyl alcohol with aniline under visible light irradiation (>400 nm). In the presence of CoW-1, the reaction conversion yield was measured as 92.6 % with turnover frequency reaching 374.4 h−1, and the apparent quantum yield at 595 nm was calculated as 17.5 %, besides, CoW-1 also exhibited high catalytic stability and reusability. To the best of our knowledge, this is the first work describing the enhanced photocatalytic performance of POMOFs based on the synergistic effect of MMCT and covalent linkage.

Photocatalytic aerobic oxidative functionalization (PAOF) reaction of benzyl alcohols by GO-MIL-100(Fe) composite in glycerol/K2CO3 deep eutectic solvent

An MIL-100 (Fe)/graphene oxide (GO) hybrid, a fairly-known composite, was made through a simple one-step procedure and played a highlighted role in the photo-induced oxidative functionalization of the benzylic C–H bond. To identify the given binary composite, various techniques were applied: FT-IR, P-XRD, SEM, nitrogen absorption–desorption analysis, TGA, TEM, and UV–Visible DRS spectra. Proportions of GO used within the structure of the prepared composite differently ranged from low to high amount, and the most optimized ratio met at 38.5% of GO as the most efficient catalyst. Additionally, the reaction ran in Glycerol/K2CO3 (2:1) as the optimal solvent. The elemental roles of O2·− and OH− were supposed to be the major ones for running a tandem oxidation-Knoevenagel reaction. The heterogeneity and reusability of the catalyst were also examined and confirmed after five successive runs.