Alumina-supported vanadyl complexes as catalysts for the CH bond activation of cyclohexene with tert-butylhydroperoxide

Salavati‐Niasari, Masoud; Elzami, M.R.; Mansournia, Mohammadreza; Hydarzadeh, Samansa

doi:10.1016/j.molcata.2004.07.007

Cited by 51 publications

(10 citation statements)

References 26 publications

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“…This Lewis order of acidity is in agreement with the catalyic activity of our samples and also with other results previously reported in the literature [48]. On other hand, TBHP as oxidant promotes the allylic oxidation pathway and minimizes the epoxidation, particularly under the highly acidic properties of catalysts [49].…”

Section: Oxidation Of Cyclohexenesupporting

confidence: 93%

Mesoporous Co3O4 as a New Catalyst for Allylic Oxidation of Cyclohexene

Azzi

Rekkab-Hammoumraoui

Chérif-Aouali

et al. 2018

Bull. Chem. React. Eng. Catal.

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Mesoporous cobalt oxide was investigated for the liquid phase oxidation of cyclohexene using tertiobutylhydroperoxide (TBHP) as an oxidant. The results were compared with several series of supported cobalt catalysts to study the influence of the cobalt loading and solvents on the overall conversion and selectivity. Mesoporous cobalt was synthesized through the nanocasting route using siliceous SBA-15 mesoporous material as a hard template and cobalt nitrate as the cobalt oxide precursor. Supported cobalt oxide catalysts (Co/MxOy) were synthesized by the impregnation method using two loadings (1 and 5 wt.%) and Al2O3, TiO2, and ZrO2 as supports. Samples were characterised by means: elemental analysis, X-ray powder Diffraction (XRD), BET (surface area), UV-Vis DR Spectroscopy, and Transmission Electron Microscopy (TEM). The results obtained showed that the cobalt oxide retains the mesoporous structure of SBA-15, and in all Co/MxOy, crystalline Co3O4, and CoO phases are observed. The mesoporous cobalt oxide is more active than the supported cobalt catalysts in the allylic oxidation of cyclohexene, with a conversion of 78 % of cyclohexene and 43.3 % selectivity toward 2-cyclohexene-1-ol. The highest activity of mesoporous cobalt oxide could be ascribed to its largest surface area. Furthermore, Co3O4 has both Lewis and Brönsted acidic sites whereas Co/MxOy has only Lewis acidic sites, which could also explain its superior catalytic activity. Moreover, mesoporous cobalt oxide was more stable than supported cobalt catalysts. Therefore, this catalyst is promising for allylic oxidation of alkenes.

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Section: Oxidation Of Cyclohexenesupporting

confidence: 93%

Mesoporous Co3O4 as a New Catalyst for Allylic Oxidation of Cyclohexene

Azzi

Rekkab-Hammoumraoui

Chérif-Aouali

et al. 2018

Bull. Chem. React. Eng. Catal.

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“…TBHP as an oxidant promotes the allylic oxidation pathway and epoxidation is minimized, especially under the acidic properties of zeolite encapsulated with divalent and trivalent transition metal ions and complexes, as also observed by us and others [32][33][34][35][36][37].…”

Section: Catalytic Activitysupporting

confidence: 74%

Host (nanopores of zeolite-Y)/guest [manganese(II) with 12-membered tetradentate N2O2, N2S2 and N4 donor macrocyclic ligands] nanocatalysts: flexible ligand synthesis, characterization and catalytic activity

Salavati‐Niasari

2008

Transition Met Chem

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Mn(II) complexes of 12-membered macrocyclic ligands with three different donating atom sets (N 2 O 2 , N 2 S 2 and N 4 ) in the macrocyclic ring have been encapsulated in the nanopores of zeolite-Y by the Flexible-Ligand Method (FLM). The complexes were entrapped in the nanocavity of zeolite-Y by a two-step process in the liquid phase: (i) adsorption of 1,2-di(o-aminophenyl-, amino, oxo, thio) ethane in the supercages of the zeolite and (ii) in situ condensation of the Mn(II) precursor complex ([Mn(N 2 X 2 )] 2+ ) with glyoxal or biacetyl. The new host-guest nanocatalysts, [Mn([R] 2 -N 2 X 2 )] 2+ -NaY (R = H, CH 3 ; X = NH, O, S), have been characterized by various physico-chemical methods. These complexes, both in their free states and as host-guest nanocatalysts, were used for oxidation of cyclohexene with tert-butylhydroperoxide (TBHP) oxidant in different solvents. Di-2-cyclohexenylether was identified as the main product. 2-Cyclohexene-1-one, 2-cyclohexene-1-ol and 1-(tert-butylperoxy)-2-cyclohexene were obtained as minor products. [Mn([H] 2 -N 4 )] 2+ -NaY was found to give the best reactivity and selectivity.

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“…Many vanadium Schiff base catalysts have been reported for alkene epoxidation. Comparison of this catalytic system with previously reported systems shows that conversion and selectivity are higher than the other systems [32,33].…”

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confidence: 66%