Aerobe Alkoholoxidation mithilfe von HNO<sub>3</sub>

Aellig, Christof; Girard, Christophe; Hermans, Ive

doi:10.1002/ange.201105620

“…No induction period was observed, in contrast to classical oxidation with HNO 3 , which indicated the absence of an autocatalytic process. [11a], …”

Section: Resultsmentioning

confidence: 99%

“…Nitric acid is an inexpensive reagent with remarkable selectivity, and similar to sodium nitrite, it is a source of nitrogen oxide and has been used successfully in the aerobic oxidation of alcohols by using different co‐catalysts such as bromine, carbon‐based catalysts, and TEMPO . If used by itself, it is necessary to perform the reaction either in concentrated sulfuric acid or under harsh reaction conditions (100 °C and 5 bar of O 2 ) in dioxane under acidic conditions with the formation of N 2 O as a side product …”

Section: Introductionmentioning

confidence: 99%

Dual Catalysis for the Aerobic Oxidation of Benzyl Alcohols – Nitric Acid and Fluorinated Alcohol

Možina

¹

,

Stavber

²

,

Iskra

³

2016

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Benzyl alcohols were oxidized with oxygen to aldehydes in excellent yields with high selectivities at room temperature. Dual catalysis was operative with HNO3 as the oxidant and precursor of the nitrogen oxides and with the use of 1,1,1,3,3,3‐hexafluoro‐2‐propanol as a template catalyst and solvent. Fluorinated alcohols also increased the selectivity by inhibiting further oxidation to benzoic acids. Activation of nitric acid catalyzed aerobic oxidation by the fluorinated solvent made the use of 2,2,6,6‐tetramethylpiperidin‐1‐oxyl (TEMPO) or a metal catalyst superfluous.

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Highly Selective Oxidation and Depolymerization of α,γ‐Diol‐Protected Lignin

Lan

¹

,

Bueren

²

,

Luterbacher

³

2019

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Lignin oxidation offers ap otential sustainable pathway to oxygenated aromatic molecules.H owever,c urrent methods that use real lignin tend to have low selectivity and ay ield that is limited by lignin degradation during its extraction. We developed stoichiometric and catalytic oxidation methods using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as oxidant/catalyst to selectively deprotect the acetal and oxidizethe a-OH into aketone.The oxidized lignin was then depolymerized using af ormic acid/sodium formate system to produce aromatic monomers with a36mol %(in the case of stoichiometric oxidation) and 31 mol %(in the case of catalytic oxidation) yield (based on the original Klason lignin). The selectivity to as ingle product reached 80 %( syringyl propane dione,and 10-13 %toguaiacyl propane dione). These high yields of monomers and unprecedented selectivity are attributed to the preservation of the lignin structure by the acetal. 1015 Lausanne( Switzerland)

show abstract

Highly Selective Oxidation and Depolymerization of α,γ‐Diol‐Protected Lignin

Lan

¹

,

Bueren

²

,

Luterbacher

³

2019

View full text Add to dashboard Cite

Lignin oxidation offers ap otential sustainable pathway to oxygenated aromatic molecules.H owever,c urrent methods that use real lignin tend to have low selectivity and ay ield that is limited by lignin degradation during its extraction. We developed stoichiometric and catalytic oxidation methods using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as oxidant/catalyst to selectively deprotect the acetal and oxidizethe a-OH into aketone.The oxidized lignin was then depolymerized using af ormic acid/sodium formate system to produce aromatic monomers with a36mol %(in the case of stoichiometric oxidation) and 31 mol %(in the case of catalytic oxidation) yield (based on the original Klason lignin). The selectivity to as ingle product reached 80 %( syringyl propane dione,and 10-13 %toguaiacyl propane dione). These high yields of monomers and unprecedented selectivity are attributed to the preservation of the lignin structure by the acetal. 1015 Lausanne( Switzerland)

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Aerobe Alkoholoxidation mithilfe von HNO₃

Cited by 12 publications

References 28 publications

Dual Catalysis for the Aerobic Oxidation of Benzyl Alcohols – Nitric Acid and Fluorinated Alcohol

Dual Catalysis for the Aerobic Oxidation of Benzyl Alcohols – Nitric Acid and Fluorinated Alcohol

Highly Selective Oxidation and Depolymerization of α,γ‐Diol‐Protected Lignin

Highly Selective Oxidation and Depolymerization of α,γ‐Diol‐Protected Lignin

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Aerobe Alkoholoxidation mithilfe von HNO3

Cited by 12 publications

References 28 publications

Dual Catalysis for the Aerobic Oxidation of Benzyl Alcohols – Nitric Acid and Fluorinated Alcohol

Dual Catalysis for the Aerobic Oxidation of Benzyl Alcohols – Nitric Acid and Fluorinated Alcohol

Highly Selective Oxidation and Depolymerization of α,γ‐Diol‐Protected Lignin

Highly Selective Oxidation and Depolymerization of α,γ‐Diol‐Protected Lignin

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Resources

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Aerobe Alkoholoxidation mithilfe von HNO₃