Oxidation–Isomerization of an Olefin to Allylic Alcohol Using Titania–Silica and a Base Co-catalyst

Beck, Carsten; Mallát, Tamás; Baiker, Alfons

doi:10.1006/jcat.2000.2975

Cited by 21 publications

(12 citation statements)

References 41 publications

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“…As a result, the industry and in turn, the society, is becoming more sustainable and eco-friendly. [9] The direct selective allylic oxidation of ISO to KET has also been demonstrated, nevertheless, it makes use of toxic heavy metals, yields undesired by-products and/or requires harsh conditions. Defined as "plant dry matter", this raw material is accessible, renewable, recyclable and vastly abundant.…”

Section: Introductionmentioning

confidence: 99%

“…[8] However, the first step (isomerization) requires the use of high temperatures and the equilibrium is shifted towards the substrate, only 2 % yield is commonly obtained. [9] The direct selective allylic oxidation of ISO to KET has also been demonstrated, nevertheless, it makes use of toxic heavy metals, yields undesired by-products and/or requires harsh conditions. [10][11][12] Apart from its biomass origin, αisophorone is also produced at large scale as a waste recovery operation from industry.…”

Section: Introductionmentioning

confidence: 99%

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Ketoisophorone Synthesis with an Immobilized Alcohol Dehydrogenase

Solé

Brummund²,

Caminal

et al. 2019

ChemCatChem

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The monoterpenoid α-isophorone is sourced from the available and renewable plant dry matter, as well as a waste recovery operation from acetone. This compound, can be hydroxylated to 4-hydroxy-isophorone which is the main precursor for the synthesis of ketoisophorone. On its turn, ketoisophorone is a key intermediate for the production of carotenoids and Vitamin E. Here, the enzymatic oxidation of 4-hydroxy-isophorone to ketoisophorone is demonstrated employing an alcohol dehydrogenase (ADHaa) from Artemisia annua and a NADPH oxidase (NOX), as a cofactor regeneration enzyme. After 24 h of reaction and an initial substrate concentration of 50 mM, 95.7 % yield and a space time yield of 6.52 g L À 1 day À 1 could be obtained. Furthermore, the immobilization of the alcohol dehydrogenase was studied on 17 different supports. An epoxy-functionalized agarose resulted in the highest metrics, 100 � 0% immobilization yield and 58.2 � 3.5 % retained activity. Finally, the immobilized ADHaa was successfully implemented in 4 reaction cycles (96 h operation) presenting a biocatalyst yield of 23.4 g product g À 1 of enzyme. It represents a 2.5-fold increase compared with the reaction with soluble enzymes.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ketoisophorone Synthesis with an Immobilized Alcohol Dehydrogenase

Solé

Brummund²,

Caminal

et al. 2019

ChemCatChem

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“…Industrially, KIP is produced from the readily available 3,5,5‐trimethyl‐2‐cyclohexen‐1‐one (α‐isophorone, α‐IP, 1 ) by isomerisation to 3,5,5‐trimethyl‐3‐cyclohexen‐1‐one (β‐isophorone, β‐IP, 2 ), followed by homogeneous liquid oxidation to KIP –. However, the isomerisation requires high temperatures and the equilibrium is still heavily shifted towards α‐IP (no more than 2 % conversion to β‐isophorone) . Therefore, the direct oxidation of α‐IP has become an attractive alternative route to KIP.…”

Section: Introductionmentioning

confidence: 99%

One‐Pot Biocatalytic Double Oxidation of α‐Isophorone for the Synthesis of Ketoisophorone

et al. 2017

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The chemical synthesis of ketoisophorone, a valuable building block of vitamins and pharmaceuticals, suffers from several drawbacks in terms of reaction conditions and selectivity. Herein, the first biocatalytic one‐pot double oxidation of the readily available α‐isophorone to ketoisophorone is described. Variants of the self‐sufficient P450cam‐RhFRed with improved activity have been identified to perform the first step of the designed cascade (regio‐ and enantioselective allylic oxidation of α‐isophorone to 4‐hydroxy‐α‐isophorone). For the second step, the screening of a broad panel of alcohol dehydrogenases (ADHs) led to the identification of Cm‐ADH10 from Candida magnoliae. The crystal structure of Cm‐ADH10 was solved and docking experiments confirmed the preferred position and geometry of the substrate for catalysis. The synthesis of ketoisophorone was demonstrated both as a one‐pot two‐step process and as a cascade process employing designer cells co‐expressing the two biocatalysts, with a productivity of up to 1.4 g L−1 d−1.

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“…The selective oxidation of (cyclic) olefins is a vital technology for fine chemicals in industry. 1,2 A relevant example is the allylic conversion of the readily available a/b-isophorones (a/b-IP) to ketoisophorone (KIP), [3][4][5][6][7][8][9][10][11][12][13][14][15][16] as KIP is an attractive candidate for various industrial applications (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Aerobic oxidation of β-isophorone catalyzed by N-hydroxyphthalimide: the key features and mechanism elucidated

Chen

Sun

Wang

et al. 2012

Phys. Chem. Chem. Phys.

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Due to the insufficient understanding of the selective oxidation mechanism of α/β-isophorones (α/β-IP) to ketoisophorone (KIP), the key features in the β-IP oxidation catalyzed by N-hydroxyphthalimide (NHPI) have been explored via theoretical calculations. β-IP is more favourable to being activated by phthalimide-N-oxyl radical (PINO˙) and peroxyl radical (ROO˙) than α-IP owing to the different C-H strengths at their reactive sites, thereby exhibiting selective product distributions. It was found that NHPI accelerates β-IP activation due to the higher reactivity of PINO˙ than ROO˙ and the equilibrium reaction between them, yielding considerable hydroperoxide (ROOH) and ROO˙. In addition, the ROOH decomposition is more favourable viaα-H abstraction by radicals than its self-dehydration and thermal dissociation. The strong exothermicity of this α-H abstraction, along with that from H-abstraction by co-yielded hot HO˙, is in favor of the straightforward formation of KIP, simultaneously leading to the isomerization of a few β-IP to α-IP and production of 4-hydroxyisophorone (HIP) and water. The proposed mechanisms, consistent with the experimental observations, allow for the deeper understanding and effective design of oxidation systems involving similar substrates or NHPI analogues that are of industrial importance.

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Oxidation–Isomerization of an Olefin to Allylic Alcohol Using Titania–Silica and a Base Co-catalyst

Cited by 21 publications

References 41 publications

Ketoisophorone Synthesis with an Immobilized Alcohol Dehydrogenase

Ketoisophorone Synthesis with an Immobilized Alcohol Dehydrogenase

One‐Pot Biocatalytic Double Oxidation of α‐Isophorone for the Synthesis of Ketoisophorone

Aerobic oxidation of β-isophorone catalyzed by N-hydroxyphthalimide: the key features and mechanism elucidated

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