Selective Oxidation Of Ethylbenzene Research Articles

Supported copper nanoarchitecture for selective ethylbenzene oxidation (EBO) reaction

Copper-based (Cu-NP) uniformly dispersed on various inorganic supports (alumina, silica, titania, and zirconia) were prepared by the reverse microemulsion technique. These nanoparticles were used for the selective oxidation of ethylbenzene (EB) to produce acetophenone (AP) as the main product in the presence of Tert‑butyl hydroperoxide(TBHP) as an oxidant. This study focused on creating Cu-nanoparticles evenly dispersed on alumina using varying Cu-loadings (5 %, 10 %, and 15% wt.) and Brij-35 as the surfactant. The resulting catalytic material was characterized using various physicochemical techniques like XRD, FESEM, HRTEM, XPS and physisorption techniques. Various parametric studies were conducted, such as the effects of temperature, catalyst support, catalyst loading, and TBHP loading to optimize the EB conversions and AP selectivity. Among the various catalyst loadings, 15 % CuO/Al2O3 (15 % of the copper content) nanocomposites showed exceptional performance, with the highest EB conversion rate (99.7 %) and AP selectivity (98.5 %) compared to other nanocomposites. The catalyst's stability and recyclability over four cycles were attributed to the strong copper oxide-alumina interaction. These findings suggest that this nanocomposite material is a promising candidate for catalytic applications, offering high selectivity and consistent EB conversion rates.

Manipulation of Electronic Effect and Assembly Architecture to Invoke Oxidation of Ethylbenzene by Hierarchical Co3O4 Wreaths.

A high-performance transition-metal oxide catalyst can be designed by appropriately integrating the concepts of morphology regulation and electronic structure modulation. In this work, hierarchical Co3O4 wreaths (CCW) enriched with oxygen vacancies (Ov) were facilely constructed for the selective oxidation of ethylbenzene (EB) to acetophenone (AP). Under the screened optimal reaction conditions, the CCW catalyst can offer a 79.1% conversion of EB (ri = 0.244 mol gcat-1 h-1) accompanied by a selectivity of 92.3% to AP. The good reaction performance can be attributed to the cooperation of defect engineering and architecture design, which can synergistically facilitate the EB oxidation performance by augmenting the intrinsic reactivity and accessibility of active sites. This work presents a reliable route to construct a high-performance transitional metal oxide catalyst via manipulation of electronic effect and assembly architecture for the selective oxidation of EB and beyond.

Novel Cobalt(II)-Decorated 1D Covalent Organic Framework for Selective Oxidation of Ethylbenzene

Novel Cobalt(II)-Decorated 1D Covalent Organic Framework for Selective Oxidation of Ethylbenzene

Cobalt Encapsulated in Nitrogen-Doped Graphite-like Shells as Efficient Catalyst for Selective Oxidation of Arylalkanes.

Selective oxidation of ethylbenzene to acetophenne is an important process in both organic synthesis and fine chemicals diligence. The cobalt-based catalysts combined with nitrogen-doped carbon have received great attention in ethylbenzene (EB) oxidation. Here, a series of cobalt catalysts with metallic cobalt nanoparticles (NPs) encapsulated in nitrogen-doped graphite-like carbon shells (Co@NC) have been constructed through the one-pot pyrolysis method in the presence of different nitrogen-containing compounds (urea, dicyandiamide and melamine), and their catalytic performance in solvent-free oxidation of EB with tert-butyl hydrogen peroxide (TBHP) as an oxidant was investigated. Under optimized conditions, the UCo@NC (urea as nitrogen source) could afford 95.2% conversion of EB and 96.0% selectivity to acetophenone, and the substrate scalability was remarkable. Kinetics show that UCo@NC contributes to EB oxidation with an apparent activation energy of 32.3 kJ/mol. The synergistic effect between metallic cobalt NPs and nitrogen-doped graphite-like carbon layers was obviously observed and, especially, the graphitic N species plays a key role during the oxidation reaction. The structure-performance relationship illustrated that EB oxidation was a free radical reaction through 1-phenylethanol as an intermediate, and the possible reaction mechanistic has been proposed.

Bridging Effect of Carbon Nitride with More Negative Conduction Potential and Halogens Promotes the Liquid-Phase Oxidation of Aromatic C-H Bonds.

The selective oxidation of benzyl C-H bonds of alkyl aromatic hydrocarbons under solvent-free conditions by using heterogeneous catalysis is a challenging task. In this work, we designed a carbon nitride photocatalyst with a high charge separation efficiency and a directed charge transfer path, which was doped with Ni and Br in the carbon nitride skeleton. Br was deposited directionally onto the electron-rich Ni surface traps to form a bond with Ni, which acted as a charge transfer bridge connecting CN and Br, resulting in a bridging effect. Photogenerated electrons were transferred from Ni target to Br, and electrons were aggregated to form a directional charge transfer path, thereby enhancing the photocatalytic performance of CN. The photocatalyst was utilized for the selective oxidation of ethylbenzene at room temperature, atmospheric pressure, and solvent-free conditions. Under batch conditions simulating solar irradiation, the conversion of ethylbenzene was 43.3% and the selectivity of the product acetophenone was up to 92.0%. With the continuous flow strategy, the conversion of ethylbenzene was increased to 52.4 and 48.1%, respectively, while the selectivity reached 92.7 and 91.0%, and the reaction time was reduced from 24 to 2.1 h. The catalyst was also found to be broadly applicable for the selective oxidation of C-H bonds in the benzyl position of alkyl aromatic hydrocarbons.

Corrigendum: Palladium‐Supported Nanoceria: A Highly Efficient Catalyst for Solvent‐Free Selective Oxidation of Ethylbenzene to Acetophenone

Corrigendum: Palladium‐Supported Nanoceria: A Highly Efficient Catalyst for Solvent‐Free Selective Oxidation of Ethylbenzene to Acetophenone

Solvent‐free selective oxidation of ethylbenzene with molecular oxygen catalyzed by cobalt catalysts supported on exfoliated carbon nitride

AbstractExfoliated graphitic carbon nitride (eg‐C3N4) material was applied as a support to load cobalt catalysts (CoOx/eg‐C3N4) through a simple impregnation method. The physical and chemical properties of the synthesized CoOx/eg‐C3N4 materials were characterized by a series of analytic techniques including XRD, SEM, FT‐IR, UV–vis, and XPS. The characterization results revealed that the introduction of Co2+ species had not altered the graphitic structure of eg‐C3N4. The Co2+ species probably coordinatively interact with the nitrogen‐containing group of eg‐C3N4. The catalytic performances of the CoOx/eg‐C3N4 were evaluated in the solvent‐free selective oxidation of ethylbenzene (EB) using molecular oxygen as an oxidant. Among the 3CoOx/eg‐C3N4 materials with various preparation temperatures, 3CoOx/eg‐C3N4‐400 exhibited the highest EB conversion, which was owing to its superior percentages of Co2+ and tertiary nitrogen species.

Atmospheric and Efficient Selective Oxidation of Ethylbenzene Catalyzed by Cobalt Oxides Supported on Mesoporous Carbon Nitride

Mesoporous carbon nitride (mpg-C3N4) was prepared by using cyanamide as a precursor and colloidal nanosilica as a template. Then, the mpg-C3N4 was used as a catalytic support to load CoOx. The physicochemical properties of the synthesized CoOx/mpg-C3N4 materials were elucidated by multiple characterization methods, and the catalytic activities were examined in the selective oxidation of ethylbenzene (EB) under atmospheric pressure by using tert-butyl hydrogen peroxide (TBHP) as an oxidant. It was found that mpg-C3N4 possessed a higher specific surface area than other carbon nitride materials, and its abundant Nb species were able to interact with Co (II) species. When the dosages of EB and TBHP were 10 mmol and 30 mmol, respectively, the reaction temperature was 100 °C, and the reaction time was 10 h, the conversion rate of ethylbenzene was 62%, and the selectivity of AP was 84.7%.

In situ-synthesized Co and N-doped mesoporous hollow silica spheres for the selective oxidation of ethylbenzene.

Transition metal and nitrogen co-doped carbon materials (M-N-C) have attracted great attention in the field of catalysis due to their high atomic utilization and outstanding catalytic performance. Herein, a series of Co and N-doped carbon catalysts (Co-N-C@mSiO2-x) were successfully prepared by pyrolysis of cobalt porphyrins in situ synthesized in the cavity of mesoporous hollow silica spheres according to a ship-in-bottle method. The optimal catalyst exhibited excellent catalytic performance for the selective oxidation of ethylbenzene, with 95.5% conversion for ethylbenzene and 98.9% selectivity toward acetophenone. In combination with characterization techniques, acid treatment experiments and KSCN poisoning tests, the successful synthesis of cobalt-porphyrins in hollow silica spheres was demonstrated, and the excellent performance of Co-N-C@mSiO2-0.10 was attributed to the more acid-resistant Co-Nx species as the main metal active center. In addition, the N-containing groups could significantly facilitate the conversion of ethylbenzene. This work is expected to provide a straightforward and green approach to design metal and N co-doped carbon materials.

Hydroxyl radical-dominated selective oxidation of ethylbenzene over a photoactive polyoxometalate-based metal-organic framework.

Realizing photo-promoted saturated C-H functionalization is a significant challenge. [CuI3(H2O)6(TPT)2][H2BW12O40]·28H2O was assembled by combining electron reservoir [BW12O40]5- with photosensitizer TPT. The continuous coordination bonds and π-π stacking interactions facilitate hole-electron separation and electron transfer, and allow it to exhibit high photocatalytic activity toward ethylbenzene oxidation with O2/H2O as oxidants.

Fabrication of a magnetic Mn(ii) cross-linked chitosan-amine/glutaraldehyde nanocomposite for the rapid degradation of dyes and aerobic selective oxidation of ethylbenzene.

Owing to the great demand for using sustainable, renewable, and widely available materials in catalytic systems for the conversion of waste/toxic material to high value-added and harmless products, biopolymers derived from natural sources have demonstrated great promise as an alternative to state-of-the-art materials that suffer from high costs and limitations. These have encouraged us to design and fabricate a new super magnetization of Mn-Fe3O4-SiO2/amine-glutaraldehyde/chitosan bio-composite (MIOSC-N-et-NH2@CS-Mn) for advanced/aerobic oxidation process. The morphological and chemical characterization of the as-prepared magnetic bio-composite was assessed using ICP-OES, DR UV-vis, BET, FT-IR, XRD, FE-SEM, HR-TEM, EDS, and XPS techniques. The PMS + MIOSC-N-et-NH2@CS-Mn system was capable of degrading methylene orange (98.9% of removal efficiency) and selectively oxidizing ethylbenzene to acetophenone (conversion 93.70%, selectivity 95.10% and TOF 214.1 (103 h-1) within 8.0 min and 5.0 h, respectively. Moreover, MO was efficiently mineralized (TOC removal of ∼56.61) by MIOSC-N-et-NH2@CS-Mn with 60.4%, 5.20, 0.03 and 86.02% of the synergistic index, reaction stoichiometric efficiency, specific oxidant efficiency, and oxidant utilization ratio in wide pH ranges, respectively. An understanding of its vital parameters and relationship of catalytic activity with structural, environmental factors, leaching/heterogenicity test, long-term stability, inhibitory effect of anions in water matrix, economic study and response surface method (RSM) were evaluated in detail. Overall, the prepared catalyst could be employed as an environmentally friendly and low-cost candidate for the enhanced activation of PMS/O2 as an oxidant. Additionally, MIOSC-N-et-NH2@CS-Mn exhibited great stability, high recovery efficiency, and low metal leaching, which eliminated the harsh condition reaction and supplied practical application performance for water purification and selective aerobic oxidation of organic compounds.

SCILL-SILP hybrid catalytic system by employing carbon nanotubes as a support for the selective oxidation of ethylbenzene to acetophenone

Hydrocarbon oxidation to more valuable products is one of the most crucial industrial petrochemical processes. To improve efficiency, economic effectiveness, and reduction of waste production by conventional processes, the development of active and selective catalysts is still an important area of research. To cope with these challenges, we developed a catalytic system that utilized molecular oxygen to oxidize ethylbenzene (EB) to acetophenone (AcPO). The catalyst was prepared by coating a thin layer of a mixture of selected ionic liquid 1-ethyl-3-methylimidazolium octylsulfate and N-hydroxyphthalimide over industrial-grade multiwalled carbon nanotubes functionalized with copper(II) ions. This unique catalyst represented a hybrid catalytic system via the combination of solid catalyst with an ionic liquid layer (SCILL) and a supported ionic liquid phase (SILP) system. The oxidation reactions were performed at 80 °C and 0.1 MPa for 6 h. SCILL-SILP hybrid catalytic system exhibited exceptional performance with ∼27 % EB conversion and ∼77 % AcPO selectivity. The recyclability and reusability of the prepared catalysts were also investigated. The copper content was determined using inductively coupled plasma mass spectrometry (ICP-MS). Scanning electron microscopy (SEM) and transmission electron microscopy(TEM)were used to study the morphologies of the catalysts. Energy dispersive spectroscopy (EDS) was used to detect the immobilized copper on the functionalized CNTs while N2 physisorption analysis was employed to study the textural properties of the catalysts. Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were used to study the freshly synthesized and recycled catalysts.

Synthesis of Nitrogen-doped Carbon Supported Cerium Single Atom Catalyst by Ball Milling for Selective Oxidation of Ethylbenzene

Synthesis of Nitrogen-doped Carbon Supported Cerium Single Atom Catalyst by Ball Milling for Selective Oxidation of Ethylbenzene

Super-paramagnetic polymer composite-supported dendrimer–Mn catalyst: Fabrication, characterization and catalytic evaluation in selective aerobic oxidation of ethylbenzene and oximes derivatives

Design of strategy and catalytic for oxidation ethylbenzene, toxic petroleum, to high value-added via hydrogen-atom-transfer process is lately attracting a renewed interest from both environmentally and economic view. Herein, novel manganese-based dendritic catalysts supported on the polymer-magnetic core-shell were synthesized, fully identified and evaluated with initiator NDHPI for selective and easy-to-handle aerobic oxidation of ethylbenzene (EB) and oximes to acetophenone (ACP) & carbonyl compounds (AH/KO), respectively. Besides mild condition reaction, the supported dendrimer-encapsulated Mn NPs also exhibited outstanding catalytic performance, such as selective oxidation of ethylbenzene and oximes using O2 as green and cheaper oxidant with excellent reactivity, selectivity, stability, and magnetic recyclability. Additionally, the effect of operating parameters such as the amount of catalyst, nature of solvent, temperature and reaction time, and role of several N-hydroxyimides were studied in the catalytic efficiency of the synthesized dendritic catalyst. The results illustrated that the enhanced catalytic efficiency of the catalyst is derived from the magnetic dendritic structures, high Mn(II) content, hydrophobic arm of dendrimers, and interaction of Mn and the dendritic framework. Finally, the reaction pathway for EB and oxime has been deduced, and the crucial role of dendritic catalyst, NDPHI, and electronic effect has been elucidated.

Unveiling the highly disordered NbO6 units as electron-transfer sites in Nb2O5 photocatalysis with N-hydroxyphthalimide under visible light irradiation

Although different NbOx units are present in Nb2O5-based catalysts, the correlations between these structures and activity remain unclear, which considerably hinders the further development of Nb2O5 photocatalysis. Herein, we utilized N-hydroxyphthalimide (NHPI) as the probe molecule to distinguish the role of different NbOx units in the activation of C–H bond under visible light irradiation. With the addition of NHPI, Nb2O5 catalysts with highly disordered NbO6 units exhibited higher activities than that with slightly disordered NbO6 units (419–495 vs. 82 μmol·g−1·h−1) in photocatalytic selective oxidation of ethylbenzene. Revealed by Raman spectra, electron paramagnetic resonance spectra, and transmission-electron-microscopy images, highly disordered NbO6 units were confirmed to act as the active sites for the transfer of photogenerated electrons from NHPI, promoting the generation of phthalimide-N-oxyl (PINO) radicals for the enhanced conversion of ethylbenzene under visible light irradiation. This study provides guidance on the role of local NbOx units in Nb2O5 photocatalysis.

Promoted selective oxidation of ethylbenzene in liquid phase achieved by hollow CeVO4 microspheres

Herein, we developed a series of CeVO4 samples with hierarchical hollow microsphere-like structure obtained at different calcination temperatures for the selective oxidation of ethylbenzene (EB) to acetophenone (AcPO) in the presence of TBHP. The optimized catalyst (CVO-500) exhibits a very high yield value of 95.0% (initial reaction rate of 49.4 mmol gcat–1 h−1) under the optimal reaction conditions. Importantly, the representative CVO-500 catalyst presents high stability, with the reaction performance well maintained after five consecutive uses. It has been indicated that the redox V5+/V3+ sites serve as the main active centers, while the electronic interaction and redox transformation between Ce and V facilitates the hopping of V5+/V3+ and the generation of oxygen vacancies. The bimetallic synergy between V and Ce thus endows the CVO-500 catalyst an excellent performance in the EB oxidation reaction. This work paves the way for the exploit of high-performance and cost-effective catalyst for the EB oxidation and beyond.

Nitrogen-doped 3D hollow carbon spheres for efficient selective oxidation of C–H bonds under mild conditions

Nitrogen-doped hollow mesoporous carbon spheres present excellent conversion and selectivity in the selective oxidation of ethylbenzene at 50 °C.

Size effect of Co–N–C-functionalized mesoporous silica hollow nanoreactors on the catalytic performance for the selective oxidation of ethylbenzene

Only the nanoreactor with suitable void size can achieve an ideal balance between enrichment and diffusion and display superior catalytic performance.

Multistep protection strategy for preparation of atomically dispersed Fe–N catalysts for selective oxidation of ethylbenzene to acetophenone

Atomically dispersed Fe atoms on three-dimensional N-doped hollow carbon spheres single-atom catalyst was prepared, which exhibit excellent catalytic performance for the catalytic oxidation of ethylbenzene under mild reaction conditions.

One-pot pyrolysis method to fabricate Co/N co-doped hollow mesoporous spheres with carbon/silica binary shells for selective oxidation of arylalkanes

Hollow mesoporous silica spheres have an excellent application prospect in the field of catalysis due to high specific surface area, tunable pore size, structural stability and void-confinement effect. In this work, rasberry-like Co/N co-doped hollow mesoporous spheres with carbon/silica binary shells were synthesized by a facile one-pot pyrolysis method, and the catalysts with different properties can be obtained easily by adjusting the factors such as the pyrolysis temperature and the introduction approach of the active substance cobalt porphyrin. The results indicated that pyrolysis temperature could exert influence on the specific surface areas and defects of catalysts. Moreover, the active sites introduced through different ways played an important role in utilizing the enrichment effect of reactants originated from the void-confinement effect. As a result, the obtained catalysts showed remarkable activity and stability for selective oxidation of ethylbenzene under moderate reaction condition. Additionally, the optimal catalyst that achieved 95.9% ethylbenzene conversion and 99.3% acetophenone selectivity also exhibited outstanding catalytic performance for lots of arylalkanes. The superior performance was due to the large specific surface area and the well-dispersed active sites stabilized by the hollow structures with carbon/silica binary shells, which could maximize the enrichment of reactants to accelerate the reaction.