Oxidation of ethyl benzene and diphenyl methane over ordered mesoporous M-MCM-41 (M=Ti, V, Cr): Synthesis, characterization and structure–activity correlations

Jha, Rani; Shylesh, S.; Bhoware, Shrikant S.; Singh, Anand

doi:10.1016/j.micromeso.2006.04.018

Cited by 75 publications

(24 citation statements)

References 27 publications

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“…This technique is generally accepted as an additionally way of establishing the element location in the silicate framework, or as extra framework species [5,10,19,29,30]. For our samples, as the content of V is increased (Table 1), the main peak corresponding to plane (100) shifted towards lower diffraction angles and a increase in the parameter a 0 , consistent with a probable incorporation of V into the siliceous structure, was observed.…”

Section: Catalyst Characterizationsupporting

confidence: 68%

“…Therefore, isomorphous substitution of silicon with a transition metal is an excellent strategy in creating catalytically active sites and anchoring sites for reactive molecules in the design of new heterogeneous nano-structured catalysts. The incorporation of vanadium, an early member of the 3d transition metal series, in the framework of molecular sieves has resulted in active catalysts for the organic transformations of various substrates using aqueous H 2 O 2 as oxidant [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

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Mesoporous Silicates with Spherical Morphology Modified with Vanadium Highly Active in Oxidation of Cyclohexene with H2O2

et al. 2011

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Vanadium-containing mesoporous molecular sieves have been prepared by hydrothermal treatment at 373 K. These materials showed spherical morphology with a narrow particle size distribution between 2 and 4 lm. The techniques used for their physicochemical characterization were: XRD, AAS, N 2 physisorption, SEM, TEM and DR-UV-Vis spectroscopy. All the materials presented high specific surface area ([900 m 2 /g), characteristic of MCM-41 materials. A well-defined mesoporous structure was observed by TEM measures although there was no onedimensional ordering of pores characteristic of such materials. Additionally, secondary mesoporosity domains were determined in the BJH size distribution. The sample synthesized with the highest content of V presented marked differences in their structural characteristics, which were attributed to the blockage of channels by the presence of nano-clusters and/or V x O y nano-oxides. From the DR-UV-Vis analysis, a successful incorporation of V ions to silica structure in tetrahedral coordination with oxygen of the network could be inferred. The catalytic activity of these materials was evaluated in the test reaction of cyclohexene oxidation using H 2 O 2 as oxidizing agent, showing a high conversion of about 93% respect to the maximum, resulting dominant the radicalary mechanism over the direct oxidation mechanism. Apparently, the isolated V ions incorporated into the silica structure would be responsible for the high catalytic activity of these materials.

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Section: Catalyst Characterizationsupporting

confidence: 68%

Section: Introductionmentioning

confidence: 99%

Mesoporous Silicates with Spherical Morphology Modified with Vanadium Highly Active in Oxidation of Cyclohexene with H2O2

et al. 2011

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“…However, when the manganese content ratio increased from 100 to 50, the intensities of the long range ordered peaks were gradually reduced [20,21]. The band observed at 220 nm is due to Si-O -bands and the other peak at 250-600 nm is due to Mn incorporation, and their intensity significantly increased with Mn content [24][25][26][27][28].…”

Section: Resultsmentioning

confidence: 99%

Mn–MCM-41 molecular sieves: a selective gas-phase cyclohexanol oxidation catalyst

Santhanaraj

Suresh

Vijayan

et al. 2010

Reac Kinet Mech Cat

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Mn-MCM-41 was synthesized by the hydrothermal method. The synthesized material was characterized by various physicochemical techniques such as small angle X-ray diffraction, elemental analysis, Fourier transform infrared spectroscopy and diffuse reflectance ultraviolet-visible spectroscopy. The gas-phase cyclohexanol and air reaction over Mn-MCM-41 molecular sieve was studied for the first time. The conversion is almost constant even up to 5 h, and follows a parabolic behavior with respect to temperature. The conversion reaches a maximum at 350°C and selectivity towards cyclohexene is increased with temperature. The conversion and cyclohexene selectivity were increased with flow rate.

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Section: Introductionmentioning

confidence: 99%

“…In some cases, it suffers from low selectivity to benzophenone [17,18,21]. 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].…”

Section: Introductionmentioning

confidence: 99%

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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Oxidation of ethyl benzene and diphenyl methane over ordered mesoporous M-MCM-41 (M=Ti, V, Cr): Synthesis, characterization and structure–activity correlations

Cited by 75 publications

References 27 publications

Mesoporous Silicates with Spherical Morphology Modified with Vanadium Highly Active in Oxidation of Cyclohexene with H2O2

Mesoporous Silicates with Spherical Morphology Modified with Vanadium Highly Active in Oxidation of Cyclohexene with H2O2

Mn–MCM-41 molecular sieves: a selective gas-phase cyclohexanol oxidation catalyst

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

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