Synthesis, Properties, and Structure of a Stable Cobalt(III) Alkyl Peroxide Complex and Its Role in the Oxidation of Cyclohexane

Chavez, Ferman A.; Nguyen, Cattien V.; Olmstead, Marilyn M.; Mascharak, Pradip K.

doi:10.1021/ic960500m

Cited by 79 publications

(88 citation statements)

References 36 publications

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“…However, cyclohexane oxidation with H 2 O 2 at low temperature using the current catalysts (such as weak acid resin, iron bispidine complexes, Ru complex, Cr/Ti/Si oxides, Na-GeX, mesoporous TS-1, Ti-MCM-41, metal aluminophosphates, biomimetic systems and Cu-Cr 2 O 3 ) invariably suffers from large amount of organic solvent (i.e. acetone and acetonitrile), poor selectivity, and low H 2 O 2 efficiency, thus making its industrialization difficult [117][118][119][120][121][122][123][124][125][126]. CDs can function not only as an efficient photocatalyst (for highly selective oxidation), but also as a multi-functional component in photocatalyst design to promote wider spectrum absorption and separation of electron-hole, as well as to stabilize photolysis semiconductors [40].…”

Section: Metal Nanoparticle/cd Complex Photocatalyst For Hydrocarbon mentioning

confidence: 99%

Catalytic Applications of Carbon Dots

Kang

Liu

2016

Carbon Nanostructures

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Carbon materials have been used for a long time in heterogeneous catalysis, which can satisfy most of the desirable properties required for a suitable catalyst support. Based on their significant advantages, such as low cost, huge amount, easy accessibility, high surface area, diverse porous structure, and resistance to acidic or basic environments, the carbon nanostructures are hungered for using as proper catalysts directly. Carbon dots (CDs), a new class of carbon nanomaterials with sizes below 10 nm, were also demonstrated to be efficient catalysts, such as, photocatalysts for selective oxidation, light-driven acid-catalysis and hydrogen bond catalysis. In this chapter, we will highlight the preparative methods, which have been used successfully to produce active, selective and durable CDs catalysts and look at their properties and the reactions which they promote. We then consider the catalysts design based on these new CDs and look into the future.

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Section: Metal Nanoparticle/cd Complex Photocatalyst For Hydrocarbon mentioning

confidence: 99%

Catalytic Applications of Carbon Dots

Kang

Liu

2016

Carbon Nanostructures

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“…These [L n Co III -OOR] complexes therefore afford RO • radicals in solution and promote alkane oxidation. 4,5,15 With olefins, one observes mostly allylic oxidation products with such [L n Co III -OOR] species. In contrast, [L n Co III -OOR] complexes with ligands that give rise to stable Co(II) species decompose via homolysis of both Co-O and O-O bonds and produce ROO • and RO • radicals in the reaction mixtures.…”

Section: Structures Of [Co(acac) 2 (Py)(oo T Bu)] (1) and [Co(acac) 2mentioning

confidence: 99%

“…As a result, these complexes initiate alkane oxidation and selective epoxidation of alkenes under different reaction conditions. 4,7,22 The ligand(s) L therefore influences the way a specific [L n Co III -OOR] complex decomposes in solution and promotes oxidation of hydrocarbons.…”

Section: Structures Of [Co(acac) 2 (Py)(oo T Bu)] (1) and [Co(acac) 2mentioning

confidence: 99%

Syntheses and Stuctures of Alkyl Peroxo Adducts of β-Diketonate Cobalt(III) Complexes and Their Role in Oxidation of Hydrocarbons and Olefin Epoxidation

et al. 1999

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To assess the oxidizing capacity of [Co( -diketonate) 2 (L)OOR] complexes, four such species, namely, [Co-(acac) 2 (L)(OO t Bu)] (acacH ) acetylacetone; L ) pyridine (py) (1), 4-methylpyridine (4-Mepy) (2), 1-methylimidazole (1-MeIm) (3)) and [Co(dbm) 2 (py)(OO t Bu)] (4, dbmH ) dibenzoylmethane), have been synthesized and the structures of 1, 3, and 4 have been determined by X-ray crystallography. Complex 1 crystallizes in the triclinic space group P1 h with a ) 9.149(2) Å, b ) 9.741(2) Å, c ) 13.067 (2) Å, R ) 84.22 (2)°, ) 77.89(2)°, γ ) 67.83(2)°, V ) 1054.1(4) Å 3 , and Z ) 2. Complex 3 crystallizes in the monoclinic space group P2 1 /n with a ) 11.341(2) Å, b ) 10.485(2) Å, c ) 18.863(2) Å, R ) 90°, ) 106.230(15)°, γ ) 90°, V ) 2153.6(8) Å 3 , and Z ) 4. Complex 4‚1.5C 6 H 6 crystallizes in the monoclinic space group P2 1 /c with a ) 14.907(5) Å, b ) 18.701-(5) Å, c ) 15.207(4) Å, R ) 90°, ) 103.52 (2)°, γ ) 90°, V ) 4122(2) Å 3 , and Z ) 4. The geometry around the Co(III) center in all four complexes is distorted octahedral, and the two -diketonate ligands are cis to each other. The Co-O and O-O bond distances in the Co-OO t Bu moiety fall in the narrow ranges of 1.860(3)-1.879 (2) and 1.451(3)-1.466(3) Å, respectively. Although stable in the solid state, these complexes decompose in benzene or halocarbon solutions to afford t BuOO • and t BuO • radicals. When alkanes like cyclohexane are present in the reaction mixture, these radicals initiate oxidation of the C-H bond. The oxidizing capacity follows the order 1 > 2 > 3 > 4. Decomposition of the complexes in the presence of cyclohexene and an aldehyde results in selective epoxidation in high yield.

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“…The cyclohexane conversion is always controlled about 4% to keep 70$85% selectivity to cyclohexanol and cyclohexanone. In recent years, many attempts have been made to improve or substitute the classical process by developing heterogeneous catalysts with oxygen or peroxides as nonpolluting oxidants under the mild conditions [1][2][3][4][5][6][7][8][9]. However, owing to low efficiency of peroxides that make the value of the oxidant higher than that of the product [10], further emphasis is given on the catalytic oxidation in liquid phase with the cheaper oxygen as oxidant [11].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization of Ag/MCM-41 and the Catalytic Performance for Liquid-phase Oxidation of Cyclohexane

et al. 2006

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Nano-scale silver supported mesoporous molecular sieve Ag/MCM-41 was directly prepared by one-pot synthesis method. The prepared sample was characterized by XRD, TEM, and N 2 sorption. The results showed that the sample of Ag/MCM-41 had no appreciable incorporation of silver into the mesoporous matrix of MCM-41 with good crystallinity, and silver nanoparticles were dispersed inside or outside of the channels in the mesoporous host. The catalytic performance of the sample for the cyclohexane liquid-phase oxidation into cyclohexanone and cyclohexanol by oxygen in the absence of solvents without inducing agents was investigated. The 83.4% selectivity to cyclohexanol and cyclohexanone at 10.7% conversion of cyclohexane was obtained over Ag/ MCM-41 catalyst at 428 K for 3 h. The turn over numbers (TONs) of Ag/MCM-41 was up to 2946. The catalytic activity of Ag/ MCM-41 was also compared with Ag/TS-1 as well as Ag/Al 2 O 3 . The results indicated that Ag/MCM-41 showed superior activity to both Ag/TS-1 and Ag/Al 2 O 3 . A calcined Ag/MCM-41 was found to be an efficient catalyst for the cyclohexane oxidation into cyclohexanol and cyclohexanone using oxygen as oxidant.

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Synthesis, Properties, and Structure of a Stable Cobalt(III) Alkyl Peroxide Complex and Its Role in the Oxidation of Cyclohexane

Cited by 79 publications

References 36 publications

Catalytic Applications of Carbon Dots

Catalytic Applications of Carbon Dots

Syntheses and Stuctures of Alkyl Peroxo Adducts of β-Diketonate Cobalt(III) Complexes and Their Role in Oxidation of Hydrocarbons and Olefin Epoxidation

Synthesis, Characterization of Ag/MCM-41 and the Catalytic Performance for Liquid-phase Oxidation of Cyclohexane

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