Liquid-phase Oxidation Of Ethylbenzene Research Articles

Activity of Manganese Carboxylates in the Process of Liquid-Phase Oxidation of Ethylbenzene with Atmospheric Oxygen

The process of oxidation of hydrocarbon with oxygen proceeds with formation of the corresponding hydroperoxide as the primary product [1,2]. A catalyst is the most important factor that influences on the direction of flow of the oxidation reaction. Catalysts based on metals of variable valency, and their derivatives are the most active in reactions of oxidation of hydrocarbon [3].

Heterogeneous liquid phase oxidation of ethylbenzene to acetophenone with graphene carbon-based catalyst

The series of graphene materials and N-doped graphene materials were successfully synthesized and improved by high-temperature treatment with trace iron oxide. XRD, Raman, FT-IR, TEM and XPS were employed for these catalysts. The catalytic performance of these catalysts was investigated in the selective oxidation of ethylbenzene with tert-butyl hydroperoxide as oxidant. The impacts of temperature, mass of catalysts, reaction time and oxidants on the selective oxidation of ethylbenzene were also investigated. The N-doped graphene materials exhibit greatly remarkable catalytic performance than others. The conversion of ethylbenzene is more than 90% and the selectivity of acetophenone is more than 95% at 353 K. Graphene can be used as catalyst owing to its unique structures and chemical properties. The characterization tests show that the doping of N atoms can create more defects and more active sites in the N-doped graphene materials which could greatly improve the catalytic performance. Furthermore, such cost-effective graphene-based catalysts possess good stability and could be reused at least five times without remarkable loss of the catalytic activity.

Facile synthesis of ordered mesoporous Cu-ZrPO with high copper contents as catalyst for liquid phase oxidation of ethylbenzene

A series of mesoporous Cu-ZrPO (M-Cu-ZrPO) materials with high specific surface area (∼200m2g−1), large pore volume (∼0.4cm3g−1), uniform pore size (∼7.8nm) and various copper contents in a wide range (0–40%) were successfully synthesized via a facile one-pot evaporation induced self-assembly (EISA) strategy. Different characterization techniques, XRD, N2-physisorption, TEM, TG-DSC, UV–vis spectra and H2-TPR were employed to investigate the mesoporous structure and copper states. The ordered mesostructure was improved with the introduction of copper species and could be successfully maintained even at a copper content up to 30%, in which the copper species were highly dispersed in the skeleton of mesostructure. Additionally, M-Cu-ZrPO exhibited excellent thermal stability and the ordered mesostructure could be successfully preserved even after treating at 700°C. Moreover, M-Cu-ZrPO was employed as catalyst for liquid phase oxidation of ethylbenzene. On account of the advantageous mesoporous structure and highly dispersed copper species, the catalytic performance of M-Cu-ZrPO was gradually improved with the increasing of copper contents and achieved the maximum at 30% copper content with 91.2% conversion of ethylbenzene and 87.0% selectivity of acetophenone. In addition, M-Cu-ZrPO showed excellent stability and reusability even after five cycles.

Enhancing the catalytic activity of carbon nanotubes by filled iron nanowires for selective oxidation of ethylbenzene

Iron nanowire filled carbon nanotubes (Fe@CNTs) were synthesized by chemical vapor deposition method and employed as heterogeneous catalysts for selective oxidation of ethylbenzene to acetophenone with molecular oxygen. The results showed that filled iron nanowires efficiently enhanced the catalytic activity of CNTs, arising from improving electron transfer. Moreover, Fe@CNTs could be easily separated from the reaction mixtures by external magnet and displayed excellent stability with no significant loss of catalytic activity after six cycling reactions. The result presented herein paves the way for the development of novel carbon catalysts for the liquid phase oxidation of ethylbenzene.

Ceria Zirconia Mixed Oxides Prepared by Hydrothermal Templating Method for the Oxidation of Ethyl Benzene

CeO2–ZrO2 oxides were prepared by the surfactant-templated method using cetyl trimethyl ammonium bromide (CTAB) as template. These were characterized by XRD, FT-IR, TEM, SEM, BET and TPD-CO2. The XRD data showed that as prepared CeO2-ZrO2 powder particles have single phase cubic fluorite structure. HRTEM shows mesoscopic ordering. Average particle size is 12-13 nm as calculated from particle histogram. The nitrogen adsorption/desorption isotherm were classified to be type IV isotherm, typical of mesoporous material. The presence of uni-modal mesopores are confirmed by the pore size distribution which shows pore distribution at around 60 A°. The catalytic activities of the prepared material were tested in liquid phase oxidation of ethylbenzene with tert-butyl hydroperoxide (TBHP) as an oxidant. Ceria zirconia catalyst modified with chromium was active for ethylbenzene conversion (65.3%) with 77% selectivity towards acetophenone. © 2013 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

Catalytic activity of MnTUD-1 for liquid phase oxidation of ethylbenzene with tert-butyl hydroperoxide

Manganese was incorporated into silica matrix of TUD-1 using tetraethylene glycol (TEG) as the template. Three samples with Si/Mn ratio of 115, 44 and 18 were prepared and characterized by various techniques. MnTUD-1 is shown to be mesoporous with tetrahedrally coordinated Mn when Si/Mn = 115; and nano-particles of manganese oxides are visible at higher loading of manganese (Si/Mn = 44 and 18). The catalytic activity of MnTUD-1 was explored in the liquid-phase oxidation of ethylbenzene with tert-butylhydroperoxide (TBHP) as oxidant. Influence of various reaction parameters such as time, Si/Mn ratio, oxidant and solvent were studied. Finally the catalytic activity also compared with well-known microporous and mesoporous catalysts like MnAlPO-5, Mn containing MCM-41, MCM-48 and SBA-15.

Copper containing TUD-1: synthesis, characterization and catalytic behavior in liquid-phase oxidation of ethylbenzene

Three dimensional amorphous mesoporous material, TUD-1 with different Cu-loading were prepared by using triethanolamine (TEA) as cheap, small, bi-functional template which acts as a mesoporous directing agent as well as an anchoring agent for copper active sites on the mesoporous wall. The materials thus prepared have been characterized by X-ray diffraction, N2 sorption, FT-IR, TEM, DR-UV–Vis and ICP-OES. The catalytic activities of the prepared material (CuTUD-1) were tested in liquid phase oxidation of ethylbenzene with tert-butyl hydroperoxide (TBHP) as an oxidant. Influence of various reaction parameters such as time, temperature, Si to Cu ratio, oxidant and solvent were studied. Isolated framework substituted Cu sites are active for ethylbenzene conversion (35.2%) with 67% selectivity towards acetophenone.

Liquid phase oxidation of ethylbenzene on pure and metal doped HS-AlF3

Abstract Pure and doped high surface aluminium fluorides (HS-AlF 3 ) with different active metal species (Fe, Mn, V, and Nb) were prepared by a sol–gel fluorination technique. The resulting solids were characterised by MAS NMR, pyridine photoacoustic spectroscopy, NH 3 TPD and O 2 chemisorption. As probe reaction for the catalytic behaviour of the samples the selective liquid phase oxidation of ethylbenzene (EB) to acetophenone (AP) was used. The catalytic behaviour strongly depends on the type and strength of the surface acid sites formed and on the oxidation capacities of the active metal sites. The best results were obtained (high EB conversion and selectivity towards AP) with the vanadium and iron doped aluminium fluoride, whereas the vanadium containing sample tends to leach under the reaction conditions.

Nickel substituted copper chromite spinels: Preparation, characterization and catalytic activity in the oxidation reaction of ethylbenzene

Nickel substituted copper chromite spinels (Cu1−xNixCr2O4, where x = 0, 0.25, 0.5, 0.75 and 1.0) were prepared by homogeneous co-precipitation method. The materials were characterized in detail by X-ray diffraction, BET surface area, scanning electron microscopy, energy dispersive X-ray analysis and FTIR spectroscopy. Powder X-ray diffraction pattern reveals the spinel phase formation and energy dispersive X-ray analysis indicates the correct stoichiometry. Liquid-phase oxidation of ethylbenzene using TBHP (70%) as an oxidant shows that the catalysts are highly active. Leaching studies performed by hot filtration experiments and reusability studies show that nickel substituted copper chromite spinels are stable under the reaction conditions.

Hydrothermal incorporation of manganese in the framework of SBA-15

Manganese incorporated SBA-15 was synthesised by pre-hydrolyzing tetraethyl orthosilicate and manganese acetate above the isoelectric point of silica using tri-block copolymer as the template. The synthesised material was characterised by XRD, N2 adsorption, ESR, SEM and AAS techniques. XRD results revealed well-ordered hexagonal array of the materials. ESR spectral studies confirmed the incorporation of manganese in the framework of assynthesised and calcined materials. Synthesis gel of higher pH favoured better incorporation of manganese in the framework. Manganese exists in bivalent and trivalent states in all the materials. Their catalytic activity was examined in the liquid phase oxidation of ethylbenzene using tert-butyl hydroperoxide as the oxidant. Acetophenone, 2-phenylethanol and 1-phenylethanol were obtained as the major products. Ethylbenzene conversion increases with increase of manganese content in the catalyst.

Vanadia supported on ceria: Characterization and activity in liquid-phase oxidation of ethylbenzene

Vanadia/ceria catalysts (2–10 wt% of V 2O 5) were prepared by wet impregnation of ammonium metavanadate in oxalic acid solution. Structural characterization was done with energy dispersive X-ray analysis (EDX), powder X-ray diffraction (XRD), BET surface area measurements, FT-IR spectroscopy and nuclear magnetic spectral analysis ( 51V MASNMR). XRD and 51V MASNMR results show highly dispersed vanadia species at lower loadings and the formation of CeVO 4 phase at higher V 2O 5 loading. The catalytic activity of catalysts was conducted in liquid phase oxidation of ethylbenzene with H 2O 2 as oxidant. The oxidation activity is increased with loading up to 8 wt% V 2O 5 and then decreased with further increase in V 2O 5 content to 10 wt%. Different vanadia species evidenced by various techniques were found to be selective towards ethylbenzene oxidation. The CeVO 4 formation associated with increased concentration of vanadia on ceria results the production of acetophenone along with 2-hydroxyacetophenone.

Cobalt-containing hexagonal mesoporous molecular sieves (Co-HMS): Synthesis, characterization and catalytic activity in the oxidation reaction of ethylbenzene

Cobalt-containing hexagonal mesoporous materials (Co-HMS and Co/HMS) with different cobalt content were synthesized for the first time by direct hydrothermal and post-synthesis (grafting) method. The materials were characterized in detail by X-ray diffraction, BET surface area, N 2 sorption isotherms, SEM, TEM, UV–vis and XPS techniques. Powder X-ray diffraction pattern, N 2 adsorption–desorption analysis and TEM analysis show the presence of hexagonal mesoporous structure, having Type IV isotherms and reveals the typical wormhole-like morphology. Spectroscopic techniques like UV–vis and XPS reveal cobalt in +2 oxidation state and tetrahedrally coordinated. Liquid phase oxidation of ethylbenzene using TBHP (70 wt%) as an oxidant shows that the catalysts are highly active, under solvent free conditions as well as under lower cobalt concentrations. Leaching studies performed by hot filtration experiments show that the cobalt catalysts prepared by hydrothermal methods are stable, while the grafted catalysts show the leaching of cobalt under the reaction conditions.

The promotional effect of CO 2 in ethylbenzene oxidation with MC-type catalytic system

The promotional effect of CO 2 in the liquid phase oxidation of ethylbenzene to acetophenone (AP) with the Co/Mn/Br (MC-type) catalyst system has been investigated. Significant enhancement of catalytic activity was found in the presence of CO 2 and thus selectivity toward acetophenone was increased as well. UV-visible investigations of the MC-type catalyst system in the oxidation of ethylbenzene reveal that Mn(III) is more easily formed in the presence of CO 2; such formation would be associated with the CO 2 promotional effect.

Ethylbenzene oxidation with air catalysed by bis(acetylacetonate)nickel(II) and tetra- n-butylammonium tetrafluoroborate

This paper deals with the liquid-phase oxidation of ethylbenzene (EB) with air to give ethylbenzene hydroperoxide (EBHP), catalysed by bis(acetylacetonate)nickel(II) and tetra- n-butylammonium tetrafluoroborate, in a stirred tank reactor, at atmospheric pressure. This catalytic system offers some advantages over the currently used industrial catalysts, and the use of a quaternary ammonium tetrafluoroborate has not been reported previously for this reaction. The effects of temperature, stirring speed, and catalysts concentration on EB conversion and EBHP selectivity and formation kinetic rate have been studied, and the optimal values found are 125°C (at atmospheric pressure), 1400 rpm and 1.5×10 −4 and 2.0×10 −3 M for bis(acetylacetonate)nickel(II) and tetra- n-butylammonium tetrafluoroborate, respectively.

A Synergy Effect of Metal Phthalocyanines and High-Valent Metal Salts Or Oxides in the Catalytic Oxidation of Ethylbenzene

The liquid phase oxidation of ethylbenzene catalyzed by metal phthalocyanines (CoPc, MnPc, and FePc) was investigated under atmospheric pressure of oxygen at 100° C. The catalytic activity of CoPc is higher than that of MnPc and FePc. The addition of catalytic amounts of K2Cr2O7, MnO2 or V2O5 to the catalytic system can lead to an increase in the catalytic activity or acetophenone selectivity, compared to that of the metal phthalocyanine and catalytic amounts of K2Cr2O7, MnO2 or V2O5 used alone.

Liquid-Phase Ethyl Benzene Oxidation Catalysed by Manganese Salts

The liquid-phase oxidation of ethyl benzene by O2 catalysed by manganese stearate (MnSt2) in a stirred batch reactor has been studied. The main reaction products are ethyl benzene hydroperoxide, methyl phenyl carbinole, and acetophenone. It was established that the reaction includes four basic macro-stages: an induction period, a period of accelerated ethyl benzene consumption, a period of slowing-down, and an inhibition step. It was shown that the initial rate of the second step is described by the equation r0 = k[EB]0 . The observed experimental data allowed the supposition that the reaction proceeds by the radical-chain mechanism with participation of hydroperoxide radicals. The overall process is possibly initiated by Mn3+ ions.

Influence of medium on lifetime and reactivity of1O2 with 1,3-diphenylisobenzofuran, and the role of1O2 in liquid-phase oxidation of ethylbenzene

1. The destruction of1O2 in the course of liquid-phase oxidation of ethylbenzene in the group of solvents examined in this work is accomplished through a mechanism of resonance transfer of energy to higher vibrational levels of the ground state of the molecules of the medium. 2. The rate constant for the chemical reaction of1O2 with 1,3-diphenylisobenzofuran (DPBF) increases with increasing dielectric constant of the medium, as a result of strong solvation of the transition complex; in high-viscosity polar solvents, the reaction rate is limited by diffusion of the molecules. 3. A substantial contribution to the reactivity of1O2 with DPBF in ethylbenzene and in methyl phenyl carbinol is made by specific interactions with the solvent molecules. 4. In the process of liquid-phase oxidation of ethylbenzene, singlet oxygen does not participate in chemical reactions leading to the formation of oxygen-containing products; deactivation of the singlet oxygen is accomplished through a physical mechanism of energy transfer to the solvent molecules.

Liquid-phase oxidation of ethylbenzene in the presence of a thiazole derivative

Research and synthesis of effective inhibitors, study of their anti-oxidizing activity during oxidation using oxygen of organic substances are of considerable practical interest for the stabilization of polymeric materials, food fats, oils, products of oil refining, etc. In addition to well-known antioxidants, such as phenols and aromatic amines, thiazole derivatives, particularly 5-benzylidenerhodanine (A), synthesized by methods previously described are of certain interest. It is known that sulfur-containing compounds inhibit oxidation by inducing the breakdown of hydroperoxides to form stable products. It was shown that 5-benzylidene rhodanine has both initiating and inhibiting action in oxidation of ethylbenzene. Inhibition with thiazole derivatives is more effective when introducing antioxidants at the initial moment of oxidation. 3 references.

Liquid-Phase Oxidation of Ethylbenzene over Cobalt Complexes Supported by Polymeric Materials

Liquid-Phase Oxidation of Ethylbenzene over Cobalt Complexes Supported by Polymeric Materials

Catalytic properties of cobalt and manganese complexes with macromolecular ligands in the liquid-phase oxidation of ethylbenzene

The selective catalytic effect of transition metal complexes (in particular cobalt and manganese) with polymeric ligands is shown on the example of the liquid-phase oxidation of ethylbenzene. The catalytic activity depends on both the structure of the polymeric matrix and the nature of metal.