Side-chain oxidation of ethylbenzene with tert-butylhydroperoxide over mesoporous Mn-MCM-41 molecular sieves

Vetrivel, Shanmugam; Pandurangan, A.

doi:10.1016/j.molcata.2004.03.022

Cited by 66 publications

(20 citation statements)

References 35 publications

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“…For the catalytic oxidationo fE Bu sing TBHP as the oxidant, the catalytic performance of as-assembled LDH/G-0.4 is superior to that of other catalysts reported previously (Table S2), [12,27,[70][71][72][73][74] despite the different reactionc onditions. We can see that overa ne xcellent supportedP d II nanoparticle catalyst, [70] the EB conversion reaches 92.3 %w ith ah igh AP selectivity of 93.5 %at130 8Cfor 12 h. Other Mn-and Co-containing heterogeneous catalysts only exhibit am oderate catalytic activity, [12,[71][72][73][74] ando ur Co-based catalyst reported previously is less activethan LDH/G-0.4. [27] As ar esult,t he CoCuAl-LDH/graphene nanocomposites are highly efficient to catalyze the oxidation of EB to AP in terms of both the activity and the selectivity to AP.I np articular,L DH/ G-0.4 is more active than other composites.…”

Section: Selectiveoxidation Of Ebmentioning

confidence: 57%

Highly Efficient Hybrid Cobalt–Copper–Aluminum Layered Double Hydroxide/Graphene Nanocomposites as Catalysts for the Oxidation of Alkylaromatics

et al. 2015

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IntroductionNowadays, the selective oxidation of inexpensive alkylaromatics to high-added-value chemicals (e.g.,k etones and aldehydes) is attracting more and more attention because of its importanceb oth in academic research and in av ariety of industrial and fine chemical processes. [1][2][3] For instance, acetophenone (AP), which is commonly produced by the selective oxidation of ethylbenzene (EB), is an important intermediate for the productiono fe sters, alcohols, aldehydes, pharmaceuticals, and resins.F rom both economic and environmental viewpoints, efficient and environmentally benign heterogeneous oxidation processes have becomea na ttractive research area. [4,5] Over the past decade, considerable endeavors have been focused on the development of non-noble-metalh eterogeneousc atalystst hat contain earth-abundant elements. These catalysts are cost effective and tolerant to deactivation in the oxidation of alkylaromatics.F or the oxidation of EB to produce AP,m any heterogeneousc atalysts, such as supported metal complexes, [6][7][8][9][10][11][12][13][14] Mn-MCM-41, [15,16] Co-HMS, [17] M-APO-11 (M = Co, V, and Mn), [18] andC eAPO-5 molecular sieves, [19] have been explored in recent years. Although severalc atalysts showed ag ood catalytic activity,ahigh selectivity to AP and ag ood stability are not easy to achieve.Layered double hydroxides (LDHs) with the formula [M 2+ + 1Àx M 3+ + x (OH) 2 ][A nÀ ] x/n ·m H 2 Oa re ac lass of 2D anionic clay materials. [20] In LDHs, divalent (e.g.,M g 2+ + ,N i 2+ + ,Z n 2+ + ,C u 2+ + , Co 2+ + ,F e 2+ + )a nd trivalent (e.g.,A l 3+ + ,F e 3+ + ,C r 3+ + ,G a 3+ + ,M n 3+ + ) metal cations prearrange in order in the layer latticesa tt he atomic level. Recently,t hese low-cost materials have attracted tremendous attention because they can be used widely as catalyst precursors, catalysts, and supports. [21] For example, Mn-or Cu-containing LDHs were found to be effective for the oxidation of EB to AP. [22][23][24][25] In most cases, LDHs only showedm oderate catalytic activity.I na ddition, calcined Cr-containing LDHs were active fort he oxidation of EB. [26] However,t he high toxicity of Cr 6+ + poses serious risks to humans and the environment. More recently,o ur group reported Co-containingm ixed metal oxidesd erived from LDH precursors that exhibited ag ood catalytic performance in the oxidation of EB with ac onversion of % 69 %a nd an AP selectivity of % 80 %. [27] Therefore, the further improvement of the catalytic performance of LDHs-based catalysts remains ac hallenging task.As the newest carbon nanomaterial, graphene with a2 D honeycombs p 2 carbon lattice possesses fascinating physiochemicalp roperties, which make it an excellent candidate for the construction of high-performance graphene-based composite nanomaterials. [28][29][30] As ac atalysts upport, graphene displays av arietyo fn ew functionalities in photocatalysis [31][32][33][34] and electrocatalysis [35][36][37][38] thanks to its larges pecific surface area, excellent conductivity fore lectron capt...

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Section: Selectiveoxidation Of Ebmentioning

confidence: 57%

Highly Efficient Hybrid Cobalt–Copper–Aluminum Layered Double Hydroxide/Graphene Nanocomposites as Catalysts for the Oxidation of Alkylaromatics

et al. 2015

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“…Since Mn 3+ is more inclined than Mn 2+ to be substituted for Si 4+ at the framework position of zeolites or MCM-41. Mn 3+ , which would have been formed during synthesis, is observed to be at least part of the Mn 3+ reduced to Mn 2+ during calcination [34]. In the as-synthesized Mn-containing aluminophosphate molecular sieves, synthesized under acidic condition, spectra similar to this were also reported [35].…”

Section: Dr Uv-vis Spectroscopymentioning

confidence: 60%

A Comparative Study on the Catalytic Activity of Mn Containing MCM-41 Molecular Sieves for Oxidation of p-Cymene

Vetrivel

Pandurangan

2007

Catal Lett

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Mesoporous silica molecular sieves SiMCM-41, AlMCM-41 with Si/Al ratio equal to 158 and MnMCM-41 with Si/Mn ratio equal to 29 were synthesized by hydrothermal method. Manganese oxide impregnated on SiMCM-41 and on AlMCM-41 catalysts were also prepared by wet impregnation method. These catalysts referred as Mn/SiMCM-41 and Mn/AlMCM-41 (158). Both the manganese incorporated and impregnated catalysts structure was elucidated by XRD. Nitrogen adsorption isotherm was used to determine specific surface area, pore volume, and pore size distribution. The thermal stability of the as-synthesized catalyst was studied using TG-DTA. The presence of Mn 2+ was evident through DR UV-VIS and ESR spectroscopy. Through ESR studies, MnMCM-41 (29) was assigned to have framework Mn(II) sites. Extraframework manganese species with well-resolved sextet, centered at g = 2.00 had octahedral symmetry was observed in Mn/SiMCM-41 and Mn/AlMCM-41 (158). Mn retained its +2 oxidation state (ESR active) even upon calcination at 550°C in presence of air. The catalytic activity of the above-mentioned manganese containing MCM-41 catalysts were tested by vapor phase oxidation of p-cymene with CO 2 -free air in the temperature range from 200 to 400°C in steps of 50°C. The major products were 4-methylacetophenone (4-MAP), 4-isopropyl benzaldehyde (4-IPB), 1,2-epoxyisopropyl benzaldehyde or 1,2-epoxycumenaldehyde (1,2-ECA) and 4-methyl styrene (4-MS). Among the product selectivity, (4-MAP) was found to be higher than that of others. The order of the activity of catalysts followed Mn/SiMCM-41 [ Mn/AlMCM-41 (158) [ Mn/SiO 2 .

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“…Formation of acetophenone requires chemi-sorption of alkyl hydroperoxide on the Lewis acid sites of the catalyst. Oxidation of the secondary carbon of ethylbenzene to 1-phenylethanol, and appropriate cleavage of bonds give acetophenone [25].…”

Section: Catalytic Activity: Oxidation Of Ethylbenzenementioning

confidence: 99%

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

Daniel

Sugunan

2013

Bull. Chem. React. Eng. Catal.

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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 was 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 Å. The catalytic activities of the prepared material were tested in liquid phase oxidation of ethylbenzene with tert-butyl hydroperoxide (TBHP) as oxidant. Ceria zirconia catalyst modified with chromium was active for ethylbenzene conversion (65.3%) with 77% selectivity towards acetophenone.

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Side-chain oxidation of ethylbenzene with tert-butylhydroperoxide over mesoporous Mn-MCM-41 molecular sieves

Cited by 66 publications

References 35 publications

Highly Efficient Hybrid Cobalt–Copper–Aluminum Layered Double Hydroxide/Graphene Nanocomposites as Catalysts for the Oxidation of Alkylaromatics

Highly Efficient Hybrid Cobalt–Copper–Aluminum Layered Double Hydroxide/Graphene Nanocomposites as Catalysts for the Oxidation of Alkylaromatics

A Comparative Study on the Catalytic Activity of Mn Containing MCM-41 Molecular Sieves for Oxidation of p-Cymene

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

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