Epoxidation of α-pinene catalysed by tetrameric cobalt(III) complexes

Chakrabarty, Rajesh; Das, Barun

doi:10.1016/j.molcata.2004.02.028

Cited by 25 publications

(20 citation statements)

References 18 publications

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“…13 The effect of reaction temperature was studied by taking 25 mg (0.08 mol%) of the catalyst and allowing the reaction to take place at 60 • C, 80 • C or 100 • C, respectively. By monitoring the progress of the reaction by GC it was found that an increase in the reaction temperature accelerates air oxidation of αpinene with the highest conversion of 66.8% being observed at 100 • C after 24 h. At all the three temperatures air oxidation commenced quickly with a preferential formation of α-pinene oxide over other oxidation products.…”

Section: Catalytic Behaviour In Aerobic Oxidationmentioning

confidence: 99%

“…More importantly, it has been found that they act as homogeneous catalysts in the oxidation of organic substrates such as alkylaromatics, alcohols and alkenes with air, oxygen or tert-butyl hydroperoxide (TBHP) as oxidants. 8,9,12,13 It is also possible to immobilize the complexes on mesoporous silica to obtain stable heterogeneous catalysts for the same reactions. 10,11 In this paper, we discuss the synthesis and physicochemical characteristics of Co(III)-oxo cubane-like clusters of the type Co 4 O 4 (O 2 CR) 4 L 4 .…”

Section: Introductionmentioning

confidence: 99%

“…GC plots under optimized conditions for the catalytic oxidation of α-pinene catalysed by a cubane complex of cobalt(III)13 .…”

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confidence: 99%

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Cobalt(III)-oxo cubane clusters as catalysts for oxidation of organic substrates

Das

Chakrabarty

2011

J Chem Sci

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Transition metal coordination complexes play a vital role as catalysts in the oxidation of organic substrates including renewable chemicals in an economically viable and environmentally friendly way. Here we highlight the preparation, characterization and application of oxo-cubane complexes of cobalt(III) as oxidation catalysts using air and water as oxidants. Cobalt(III)-oxo complexes of the type Co 4 O 4 (O 2 CR) 4 L 4 have been prepared by a general method and these have been characterized by analytical, spectroscopic, electrochemical and crystallographic methods. These soluble complexes have shown promising utility as catalysts in the aerobic oxidation of side chains of alkylaromatic hydrocarbon compounds. Oxidation of neat ethylbenzene has shown very high conversion and selectivity for acetophenone formation. On the other hand, oxidation of p-xylene has been found to yield both p-toluic acid and terephthalic acid. It is also possible to oxidize p-xylene in an aqueous medium under moderate applied O 2 pressure. Selective epoxidation of α-pinene with air as the oxidant also takes place with the cobalt(III)-based homogeneous catalysts.

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Section: Catalytic Behaviour In Aerobic Oxidationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cobalt(III)-oxo cubane clusters as catalysts for oxidation of organic substrates

Das

Chakrabarty

2011

J Chem Sci

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“…(18)) has been examined as a catalyst for the homogeneous air oxidation of α-pinene under atmospheric pressure. High selectivity (62-68%) for α-pinene oxide formation is observed, even if yield is far from satisfactory [112]. Different immobilized silver catalysts have been prepared and used in the oxidation of alkenes.…”

Section: Other Metals and Seleniummentioning

confidence: 99%

Recent Developments in Epoxide Preparation

Sello¹,

Fumagalli²,

Orsini³

2006

COS

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This review will present recent achievements in the use of novel reactants and synthetic procedures for the transformation of substrates into epoxide derivatives. This will include both classical chemical methods using novel catalysts and/or cleaner methodologies, and enzymatic preparations using enzymes or cells. Special attention is paid to the preparation of chiral compounds. A comparison of the advantages and disadvantages of the different preparations is also included.

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“…Earlier studies have shown that the cubane cluster, [Co III 4 O 4 (O 2 CC 6 H 5 ) 4 (4-CNpy) 4 ] (I) displays excellent catalytic activity in the epoxidation of a-pinene under homogeneous conditions. 11 In the synthesis of these cobalt(III) species via H 2 O 2 oxidation, it has been our observation that it is always the tetramer which can be isolated in high yield from a reaction mixture involving a cobalt(II) salt, a sodium carboxylate, the selected pyridine, along with H 2 O 2 (aq.) oxidant, added in excess, in methanol.…”

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confidence: 99%