Kinetic and selectivity control of TEMPO electro-mediated oxidation of alcohols

Liaigre, Denis; Breton, Tony; Belgsir, E.M.

doi:10.1016/j.elecom.2005.01.002

Cited by 52 publications

(46 citation statements)

References 7 publications

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“…The unprotected anomeric position and the osidic bond were both oxidized by the oxoammonium salt leading to cleavage of the molecule. This lack of selectivity, due to the presence of free aldehyde group, is also confirmed by Liaigre et al (2005). In comparison with usual chemistry, the mediated electrochemical oxidation facilitates the reaction process by the control of the reaction potential, and allows an easy recovering of the reaction products in the absence of oxidizing agents as NaOCl/NaCl.…”

Section: Discussionsupporting

confidence: 52%

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TEMPO mediated oxidation of carbohydrates using electrochemical methods

et al. 2010

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The oxidation of some readily available carbohydrates was investigated in aqueous medium using a catalytic amount of 2,2,6,6-Tetramethyl-1-piperidinyl-oxy (TEMPO) as redox mediator. The regeneration of oxoammonium (active form) was electrochemically performed in alkaline medium at a glassy carbon anode and at controlled potential (0.5 V vs. AgCl/Ag). The primary alcohol groups of the carbohydrates without free aldehyde group, were selectively oxidized to the corresponding sodium uronate with high Faradaic yields. The presence of free aldehyde or hemiacetal groups leads to a decrease in selectivities towards uronic acids and increases the amount of by-products.

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Section: Discussionsupporting

confidence: 52%

“…Heterogeneous systems involving anodic regeneration of TEMPO ? were applied to oxidize some mono and disaccharides in excellent to moderate yields (Liaigre et al 2005;Schämann and Schäfer 2005).…”

Section: Introductionmentioning

confidence: 99%

TEMPO mediated oxidation of carbohydrates using electrochemical methods

et al. 2010

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“…TEMPO electro-mediated reactions were reported as green chemical processes for selective oxidation of primary hydroxyls of carbohydrates (Schnatbaum and Schäfer 1999;Belgsir and Schäfer 2001;Liaigre et al 2005;Parpot et al 2010;Isogai et al 2010a). When mono-, di-and tri-saccharides were oxidised by electro-mediated reactions with a TEMPO catalyst in carbonate buffers at pH 10, the corresponding C6-carboxylate compounds were obtained in the yields of 22-99% (Schnatbaum and Schäfer 1999;Belgsir and Schäfer 2001;Liaigre et al 2005;Parpot et al 2010). Seventy four and 63% of the C6-primary hydroxyls of b-cyclodextrin and potato stach, respectively, were converted to C6-carboxyl groups by the TEMPO electro-mediated oxidation at pH 10 (Schnatbaum and Schäfer 1999).…”

Section: Introductionmentioning

confidence: 99%

Wood cellulose nanofibrils prepared by TEMPO electro-mediated oxidation

2010

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A softwood bleached kraft pulp (SBKP) was subjected to electro-mediated oxidation in water with TEMPO or 4-acetamido-TEMPO without any chlorine-containing oxidant. Solid recovery ratios of water-insoluble fractions of the oxidized SBKPs were more than 80%, and C6-carboxylate contents increased up to approximately 1 mmol g -1 after oxidation for 48 h. Significant amounts of C6-aldehyde groups (0.17-0.38 mmol g -1 ) were also formed in the oxidized SBKPs. The degree of polymerization decreased from 2,200 to 520 and 1,400 by the oxidation for 48 h with TEMPO at pH 10 and 4-acetamido-TEMPO at pH 6.8, respectively. The original cellulose I crystal structure and crystallinity of SBKP were maintained after the oxidation, indicating that all C6-oxidized groups were selectively formed on crystalline cellulose microfibril surfaces. The oxidized SBKPs with carboxylate contents of more than 0.9 mmol g -1 were convertible to individual cellulose nanofibrils in yields of more than 80% by disintegration in water.

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“…Hence, for example, whereas benzyl alcohol in water in the presence of TEMPO is rapidly oxidised to benzoic acid [6], the use of the hydrophobic electrode TEM-PO@DE uniquely affords benzaldehyde by preventing diffusion of the hydrated aldehyde molecules (gem-diol) to the hydrophobic surface of the ORMOSIL electrode. In this paper we show how the nanostructure affects the catalytic performance of these molecular electrodes and suggest the origin of the superior performance of the organosilica electrode.…”

Section: Introductionmentioning

confidence: 99%

Structural insight on organosilica electrodes for waste-free alcohol oxidations

et al. 2007

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Organic modification of sol-gel catalytic glassy electrodes made of a thin layer of organosilica doped with nitroxyl radical TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) crucially enhances stability in the waste-free oxidation of alcohols to carbonyls in water. Structural comparison between analogous films made of organosilica and unmodified SiO 2 shows that the origin of the pronounced stable activity of the ORMOSIL film lies in high hydrophobic and also in the pronounced low degree of hydrophilicity.

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Kinetic and selectivity control of TEMPO electro-mediated oxidation of alcohols

Cited by 52 publications

References 7 publications

TEMPO mediated oxidation of carbohydrates using electrochemical methods

TEMPO mediated oxidation of carbohydrates using electrochemical methods

Wood cellulose nanofibrils prepared by TEMPO electro-mediated oxidation

Structural insight on organosilica electrodes for waste-free alcohol oxidations

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