Role of vanadium alkylperoxo complexes in epoxidation of cyclohexene and oxidation of cyclohexane by organic hydroperoxides in the presence of bis (acetylacetonato)vanadyl

Talsi, Evgenii P.; Chinakov, V. D.; Babenko, V. P.; Zamaraev, K. I.

doi:10.1016/0304-5102(93)80009-j

Cited by 55 publications

(30 citation statements)

References 14 publications

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“…This comparison is only valid when the vanadium in solution has similar reactivity, regardless the vanadium species originate from VO(acac)2 or VAPO-5. Mechanistic investigations show that vanadium complexes are immediately converted to a vanadium peroxo complexes while in contact with the solution, resulting in comparable activities [13]. For example, the difference in reaction rate in the oxidation of cyclohexene with TBHP between the least active catalyst, VO(acac)2 and the most active catalyst (nBuO)3VO is only 3.7 [14].…”

Section: Re-use Of Vapo-5mentioning

confidence: 99%

VAPO as catalyst for liquid phase oxidation reactions. Part II: stability of VAPO-5 during catalytic operation

Haanepen

Elemans-Mehring

Hooff

1997

Applied Catalysis A: General

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Section: Re-use Of Vapo-5mentioning

confidence: 99%

VAPO as catalyst for liquid phase oxidation reactions. Part II: stability of VAPO-5 during catalytic operation

Haanepen

Elemans-Mehring

Hooff

1997

Applied Catalysis A: General

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“…Many catalytic systems based on transitionmetal complexes of Mo, Ti, W and V have been reported and found to be very effective and selective for the epoxidation of a wide range of (cyclo)alkenes using hydroperoxides as oxidant [1][2][3]. The reaction chemistry of vanadyl acetylacetonate (VO(acac) 2 ) as catalyst for the oxidation of cyclohexene with hydrogen peroxide or tert-butyl hydroperoxide (TBHP) as oxidant has been the subject of several experimental studies [4][5][6][7][8]. Recently, the homogeneous VO(acac) 2 /TBHP system and the porous metal organic framework type catalyst MIL-47 [9] have been compared for their cyclohexene epoxidation activity and they showed similar conversion patterns [10,11].…”

Section: Introductionmentioning

confidence: 99%

“…The most abundant oxidation product of Hacac was found to be acetic acid (HOAc) [7,23]. Furthermore, certain studies have tried to unravel the initial steps in the reaction of VO(acac) 2 with TBHP [7,8]. The active intermediates were widely accepted to be vanadium(+V) alkylperoxo complexes in the VO(acac) 2 /TBHP [4,16,17,22] and VO(acac) 2 /TBHP/ligand [24][25][26][27][28] catalytic systems.…”

Section: Introductionmentioning

confidence: 99%

“…The active intermediates were widely accepted to be vanadium(+V) alkylperoxo complexes in the VO(acac) 2 /TBHP [4,16,17,22] and VO(acac) 2 /TBHP/ligand [24][25][26][27][28] catalytic systems. More specifically, Talsi et al [8] investigated the role of alkylperoxo complexes for the cyclohexene epoxidation with organic hydroperoxides in presence of VO(acac) 2 in detail by NMR and EPR. Experimentally, V +V alkylperoxo species (V +V O(OOtBu)) have been thought to epoxidize cyclohexene [8].…”

Section: Introductionmentioning

confidence: 99%

“…More specifically, Talsi et al [8] investigated the role of alkylperoxo complexes for the cyclohexene epoxidation with organic hydroperoxides in presence of VO(acac) 2 in detail by NMR and EPR. Experimentally, V +V alkylperoxo species (V +V O(OOtBu)) have been thought to epoxidize cyclohexene [8]. Those alkylperoxo species are also able to oxidize cyclohexane, but only through radical generation via the equilibrium V +V O(OOR) V +IV O + •OOR.…”

Section: Introductionmentioning

confidence: 99%

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Mechanistic insight into the cyclohexene epoxidation with VO(acac)2 and tert-butyl hydroperoxide

Vandichel

Leus

Voort

et al. 2012

Journal of Catalysis

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The epoxidation reaction of cyclohexene is investigated for the system vanadyl acetylacetonate (VO(acac) 2 ) as catalyst with tert-butyl hydroperoxide (TBHP) as oxidant with the aim to identify the most active species for epoxidation and to retrieve insight into the most plausible epoxidation mechanism. The reaction mixture is composed of various inactive and active complexes in which vanadium may either have oxidation state +IV or +V. Inactive species are activated with TBHP to form active complexes. After reaction with cyclohexene each active species transforms back into an inactive complex which may be reactivated again. The reaction mixture is quite complex containing hydroxyl, acetyl acetonate, acetate or a tert-butoxide anion as ligands and thus various ligand exchange reactions may occur among active and inactive complexes. Also radical decomposition reaction allow transforming V +IV to V +V species. To obtain insight into the most abundant active complexes, each of previous transformation steps has been modeled through thermodynamic equilibrium steps. To unravel the nature of the most plausible epoxidation mechanism, first principle chemical kinetics calculations have been performed on all proposed epoxidation pathways. Our results allow to conclude that the concerted Sharpless mechanism is the preferred reaction mechanism and that alkylperoxo species V +IV O(L)(OOtBu) and V +V O(L 1 )(L 2 )(OOtBu) species are most abundant. At the onset of the catalytic cycle vanadium +IV species may play an active role but as the reaction proceeds, reaction mechanisms that involve vanadium +V species are preferred as the acetyl acetonate is readily oxidized. Additionally an experimental IR and kinetic study has been performed to give a qualitative composition of the reaction mixture and to obtain experimental kinetic data for comparison with our theoretical values. The agreement between theory and experiment is satisfactory.

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Potential Degradation of 4‐Methyltetrahydropyran (4‐MeTHP) under Oxidation Conditions

Kobayashi

Tamura

2021

Asian J Org Chem

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4‐Methyltetrahydropyran (4‐MeTHP) is a next‐generation recyclable ether solvent that can be applied to a wide variety of synthetic reaction methods. Previous studies indicated that 4‐MeTHP could degrade to some extent with certain oxidants, while the oxidation reactions themselves proceeded in good yields. Here we disclose the potential oxidative degradation pathways of 4‐MeTHP when exposed to selected organic‐based and metal‐based oxidants. Crude NMR analyses revealed that degradation of 4‐MeTHP was initiated by C2−H abstraction, giving rise to C2‐ or C4‐oxidized products or the C−C bond cleavage product depending on the oxidants used. This study therefore illustrates possible degradation products of 4‐MeTHP under oxidative conditions, which is particularly helpful in predicting and analyzing trace impurities when adopting 4‐MeTHP or other ethereal solvents in industrial processes.

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Role of vanadium alkylperoxo complexes in epoxidation of cyclohexene and oxidation of cyclohexane by organic hydroperoxides in the presence of bis (acetylacetonato)vanadyl

Cited by 55 publications

References 14 publications

VAPO as catalyst for liquid phase oxidation reactions. Part II: stability of VAPO-5 during catalytic operation

VAPO as catalyst for liquid phase oxidation reactions. Part II: stability of VAPO-5 during catalytic operation

Mechanistic insight into the cyclohexene epoxidation with VO(acac)2 and tert-butyl hydroperoxide

Potential Degradation of 4‐Methyltetrahydropyran (4‐MeTHP) under Oxidation Conditions

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