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

Bhoware, Shrikant S.; Shylesh, S.; Kamble, K.R.; Singh, Anand

doi:10.1016/j.molcata.2006.03.072

Cited by 72 publications

(28 citation statements)

References 24 publications

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“…With H 2 O 2 and NaOCl, negligible conversion of diphenylmethane was obtained (1.5 and 2.5% with H 2 O 2 and NaOCl, respectively). The same result was found in the oxidation of ethylbenzene [22,23]. This may be due to rapid decomposition of H 2 O 2 without being involved in the oxidation reaction over these catalysts.…”

Section: Resultssupporting

confidence: 76%

“…Detailed characterization of these materials has been reported by us [22,23]. Powder X-ray diffraction confirmed the well ordered mesoporous structure of the cobalt containing MCM-41 and HMS materials with different ratios of Si/Co (Fig.…”

Section: Resultssupporting

confidence: 52%

“…Our group reported the oxidation of diphenylmethane over metal incorporated molecular sieves (M-MCM-41 were M is Ti, V, Cr) using H 2 O 2 as oxidant [21]. We found that cobalt containing HMS and MCM-41 showed good catalytic activity and selectively in liquid phase oxidation of ethylbenzene [22,23]. Here, we have reported use of cobalt containing HMS and MCM-41 for the liquid phase oxidation of diphenylmethane using TBHP as oxidant.…”

Section: Introductionmentioning

confidence: 95%

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Catalytic Activity of Cobalt Containing MCM-41 and HMS in Liquid Phase Oxidation of Diphenylmethane

2009

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Cobalt containing MCM-41 and HMS were synthesized by direct hydrothermal (DHT) and post synthesis methods (grafting and immobilization). The catalytic activity of these materials was investigated in the liquid phase oxidation of diphenylmethane at 80°C with TBHP (70 wt%) as oxidant. Comparative study of cobalt containing MCM-41 and HMS was carried out to reveal the catalytic performance of framework, extraframework and immobilized cobalt species. The role of the solvent in the performance of catalyst was examined with different polar and non polar solvents. Oxidation of diphenylmethane in solvent free media (under similar reaction conditions) shows formation of hydroxy derivatives of benzophenone in addition to main product (benzophenone). Hundred percent selectivity to benzophenone was obtained when the reaction was carried out in solvent.

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Section: Resultssupporting

confidence: 76%

Section: Resultssupporting

confidence: 52%

Section: Introductionmentioning

confidence: 95%

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Catalytic Activity of Cobalt Containing MCM-41 and HMS in Liquid Phase Oxidation of Diphenylmethane

2009

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“…Oxidation of benzoin is a practically important reaction for the production of benzil or benzaldehyde required in the perfumery and pharmaceutical industries [12][13][14][15][16][17]. Few heterogeneous catalytic methods have been developed for the oxidation of ethylbenzene, benzoin and cyclohexanol [18][19][20][21][22][23]. Recently we have reported ruthenium(III), copper(II) and zinc(II) complexes of imidazole encapsulated in zeolite-Y having potential catalytic activities for the oxidation of ethylbenzene.…”

Section: Introductionmentioning

confidence: 99%

Zeolite encapsulated Ru(III), Cu(II) and Zn(II) complexes of benzimidazole as reusable catalysts for the oxidation of organic substrates

Bhagya

Gayathri

2013

J Porous Mater

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Ru(III), Cu(II) and Zn(II) complexes of benzimidazole (BzlH) have been synthesized in the supercages of zeolite-Y by the flexible ligand method and were characterized by spectroscopic (IR, UV-Vis and ESR) studies, XRD and thermogravimetric analysis, surface area, and pore volume measurements. The zeolite encapsulated complexes catalyzed the oxidation of ethylbenzene, benzoin, and cyclohexanol. Various parameters, such as concentration of oxidant and catalyst, reaction time, temperature of the reaction and type of solvents have been optimized to obtain the maximum transformation of ethylbenzene to a mixture of acetophenone, benzaldehyde and styrene. Under the optimized reaction conditions, [Ru(BzlH)]-Y gave 80.4 % conversion of ethylbenzene in 1 h. All these zeolite encapsulated complexes were more selective towards acetophenone formation. Oxidation of benzoin catalyzed by [Cu(BzlH)]-Y, [Ru(BzlH)]-Y and [Zn(BzlH)]-Y encapsulated complexes resulted in 75.5, 78.7 and 59.9 % conversion respectively to give benzaldehyde as exclusive product. A maximum conversion of 39.1 % cyclohexanol with [Cu(BzlH)]-Y was achieved to give cyclohexanone. The activity of neat complexes towards these reactions was also carried out. The encapsulated catalysts were significantly more active than neat complexes and recyclable without much loss in catalytic activity.

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“…[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.…”

mentioning

confidence: 99%

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

Cited by 72 publications

References 24 publications

Catalytic Activity of Cobalt Containing MCM-41 and HMS in Liquid Phase Oxidation of Diphenylmethane

Catalytic Activity of Cobalt Containing MCM-41 and HMS in Liquid Phase Oxidation of Diphenylmethane

Zeolite encapsulated Ru(III), Cu(II) and Zn(II) complexes of benzimidazole as reusable catalysts for the oxidation of organic substrates

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

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