Highly selective oxidation of cyclohexene to 2-cyclohexene-1-one over polyoxometalate/metal–organic framework hybrids with greatly improved performances

Tong, Jinhui; Wang, Wenhui; Su, Lingdi; Li, Qing; Liu, Fangfang; Ma, Wenmei; Lei, Ziqiang; Bo, Lili

doi:10.1039/c6cy01554a

Cited by 57 publications

(32 citation statements)

References 39 publications

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“…It allows us to keep the double bond and at the same time create a new alcohol or carbonyl function . As such, it is useful across the board, from bulk chemicals and agrochemicals all the way to fine chemicals and fragrances . In theory, allylic oxidation is a straightforward exothermic reaction.…”

Section: Introductionsupporting

confidence: 65%

“…Notably, the difference in the surface area between the carbon and the γ‐alumina was corrected for by increasing the catalyst amount accordingly. To boost the number of free radicals at the start of the reaction, we added H 2 O 2 (13 mol % relative to the substrate, entry 3) . H 2 O 2 can decompose into water and oxygen under these reaction conditions.…”

Section: Resultsmentioning

confidence: 99%

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Selective Catalytic Oxidation of Cyclohexene with Molecular Oxygen: Radical Versus Nonradical Pathways

et al. 2018

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We study the allylic oxidation of cyclohexene with O2 under mild conditions in the presence of transition‐metal catalysts. The catalysts comprise nanometric metal oxide particles supported on porous N‐doped carbons (M/N:C, M=V, Cr, Fe, Co, Ni, Cu, Nb, Mo, W). Most of these metal oxides give only moderate conversions, and the majority of the products are over‐oxidation products. Co/N:C and Cu/N:C, however, give 70–80 % conversion and 40–50 % selectivity to the ketone product, cyclohexene‐2‐one. Control experiments in which we used free‐radical scavengers show that the oxidation follows the expected free‐radical pathway in almost all cases. Surprisingly, the catalytic cycle in the presence of Cu/N:C does not involve free‐radical species in solution. Optimisation of this catalyst gives >85 % conversion with >60 % selectivity to the allylic ketone at 70 °C and 10 bar O2. We used SEM, X‐ray photoelectron spectroscopy and XRD to show that the active particles have a cupric oxide/cuprous oxide core–shell structure, giving a high turnover frequency of approximately 1500 h−1. We attribute the high performance of this Cu/N:C catalyst to a facile surface reaction between adsorbed cyclohexenyl hydroperoxide molecules and activated oxygen species.

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Section: Introductionsupporting

confidence: 65%

Section: Resultsmentioning

confidence: 99%

Selective Catalytic Oxidation of Cyclohexene with Molecular Oxygen: Radical Versus Nonradical Pathways

et al. 2018

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“…To our knowledge, only a few publications involving allylic oxidation can be found about the oxidation of cycloalkenes catalyzed by TMSPs with H 2 O 2 or O 2 . Mizuno et al.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the mechanism of allylic oxidation catalyzed by TMSPs remains unknown, and the effect of H 2 O 2 on the stability of TMSPs is usually ignored. Recently, H 3+ x PMo 12− x V x O 40 ( x= 1, 2)/metal‐organic framework hybrids were prepared by a direct hydrothermal method for catalyzing the allylic oxidation of cyclohexene …”

Section: Introductionmentioning

confidence: 99%

Oxidation of Cyclohexene in the Presence of Transition‐Metal‐Substituted Phosphotungstates and Hydrogen Peroxide: Catalysis and Reaction Pathways

et al. 2017

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Homogeneous catalytic oxidations of cyclohexene by transition‐metal‐substituted phosphotungstates [PW11M(L)O39]m− (PW11M, M=CoII, CuII, FeIII, NiII, MnII, L=H2O or absence) with hydrogen peroxide in acetonitrile were experimentally studied. The catalytic activities of allylic oxidation were found to strongly depend on the transition metals, and PW11Co showed the highest activity. The product distribution and the catalyst stability were dominated by mole ratio of hydrogen peroxide to PW11M, whereby low or high mole ratios led to stable structure of PW11M and predominant formation of allylic oxidation products or decomposition of PW11M, respectively. Different from the activation of the allylic C−H bond by radicals, the oxidation of C=C double bond was based on tungsten‐peroxo species. A reaction mechanism composed of radical and nonradical processes was proposed from NMR, EPR, and kinetic data, to describe the reaction pathways of cyclohexene oxidation.

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“…Moreover the observed broad band centered at 3400 cm −1 is attributed to O‐H stretching vibration in the structure of PMoV 2. The FTIR spectrum of PMoV 2 ‐IL‐Al‐MCM‐41 shows the characteristic bands related to ILBr‐Al‐MCM‐41 along with three new bands at 949, 875 and 796 cm −1 attributed to the Keggin structure of PMoV 2 where the other main vibrational band of this unit is overlapped with the Si‐O‐Si asymmetric stretching vibration in Al‐MCM‐41.…”

Section: Resultsmentioning

confidence: 99%

Organic–inorganic hybrid of anchored dicationic ionic liquid on Al‐MCM‐41‐phosphovanadomolybdate toward selective oxidation of benzene to phenol

Taheri

Ghiaci

Moheb

et al. 2019

Applied Organom Chemis

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A phosphovanadomolybdate hybridized with an anchored dicationic ionic liquid on Al-MCM-41 was prepared through the anion exchange and characterized by 1 H and 13 C NMR, FTIR, UV-Vis, XRD, XPS, TGA, TEM, FESEM, ICP-OES and BET techniques. The obtained data demonstrated that the composite is a porous material with the high surface area and also having a large pore volume which are 405 m 2 g −1 and 0.616 cm 3 g −1 respectively. The prepared composite has shown an acceptable catalytic activity for converting benzene selectively to phenol with hydrogen peroxide as eco-friendly oxidant.Under the optimized reaction conditions, the hybrid catalyst resulted in phenol yield of 14.8% with 100% selectivity and a TOF value of 20.0 h −1 . The catalyst also revealed a desired recovery and reusability. The efficient performance of the composite is related to the textural and polyoxometalate properties.

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Highly selective oxidation of cyclohexene to 2-cyclohexene-1-one over polyoxometalate/metal–organic framework hybrids with greatly improved performances

Abstract: H3+xPMo12−xVxO40@MIL-100 (Fe) (x = 0, 1, 2) hybrids were prepared by encapsulation of polyoxometalates (POMs) within the metal–organic framework using a direct hydrothermal method.

Cited by 57 publications

References 39 publications

Selective Catalytic Oxidation of Cyclohexene with Molecular Oxygen: Radical Versus Nonradical Pathways

Selective Catalytic Oxidation of Cyclohexene with Molecular Oxygen: Radical Versus Nonradical Pathways

Oxidation of Cyclohexene in the Presence of Transition‐Metal‐Substituted Phosphotungstates and Hydrogen Peroxide: Catalysis and Reaction Pathways

Organic–inorganic hybrid of anchored dicationic ionic liquid on Al‐MCM‐41‐phosphovanadomolybdate toward selective oxidation of benzene to phenol

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