The effect of reaction conditions on the oxidation of veratryl alcohol catalyzed by cobalt salen-complexes

Kervinen, Kaisa; Lahtinen, Petro; Repo, Timo; Svahn, Minna; Leskelä, Markku

doi:10.1016/s0920-5861(02)00064-0

Cited by 32 publications

(27 citation statements)

References 27 publications

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“…Based on the presented results and supported by our earlier studies, [16][17] the oxidation of veratryl alcohol in water catalyzed by Co(salen) and oxygen is suggested to proceed through the steps described in Scheme 2. The cycle of veratryl alcohol oxidation starts with a bis-μ-hydroxo[Co(salen)] 2 complex A, which can deprotonate a substrate molecule at temperature higher than 60°C forming an alkoxo intermediate B and water.…”

Section: Discussionsupporting

confidence: 78%

“…It was already suggested before, that substrate coor-dination must be necessary for the reaction to occur as the strongly binding axial bases inhibit the reaction and the high substrate to metal ratio enhances it. [16][17] ATR-IR spectra show clearly that an intermediate species is formed between veratryl alcohol and Co(salen). This intermediate B exhibits a strong vibration at 993 cm -1 corresponding to the C-O bond of the metal-bound alkoxo group.…”

Section: Formation Of the Intermediate Bmentioning

confidence: 99%

“…[3,15] In this study, Co(salen) is used as a catalyst to oxidize a lignin model compound, veratryl alcohol (3,4-dimethoxybenzyl alcohol), to an aldehyde in alkaline water solution. Selective oxidation of lignin would be attractive for catalytic pulp bleaching [16][17][18] and for the search of renewable raw materials. [3,12] This reaction proceeds in the presence of molecular oxygen to reach TOF = 10-15 at optimum conditions (TOF = turnover frequency, moles of product per mol of catalyst per hour).…”

Section: Introductionmentioning

confidence: 99%

“…[16] The effect of reaction conditions observed previously for this system suggest that a mononuclear superoxo complex is not responsible for catalytic activity. [16][17] However, direct proof for the intermediates involved in the catalytic cycle is lacking. Temperature and pH have a dramatic effect on the catalytic activity of this system, and thus it is vital that the mechanism is studied under real experimental conditions.…”

Section: Introductionmentioning

confidence: 99%

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Mechanistic Insights into the Oxidation of Veratryl Alcohol with Co(salen) and Oxygen in Aqueous Media: An in‐situ Spectroscopic Study

et al. 2005

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Section: Discussionsupporting

confidence: 78%

Section: Formation Of the Intermediate Bmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mechanistic Insights into the Oxidation of Veratryl Alcohol with Co(salen) and Oxygen in Aqueous Media: An in‐situ Spectroscopic Study

et al. 2005

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“…Veratryl alcohol (3,4-dimethoxybenzyl alcohol) is a commonly used lignin model [27]. This substrate is optimal for our experiments since Complexes 1-6 have no absorbance at 310 nm, whereas its oxidized product veratraldehyde absorbs strongly at 310 nm (ε = 9300 M…”

Section: Oxidation Of the Lignin Analogue Veratryl Alcoholmentioning

confidence: 99%

Biomimetic Catalysts for Oxidation of Veratryl Alcohol, a Lignin Model Compound

et al. 2013

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Abstract:Kraft pulp has to be bleached to eliminate the chromophoric structures, which cause a darkening of the pulp. In Nature, an equivalent role is assumed by ligninolytic enzymes such as lignin peroxidases, manganese peroxidases and laccases. The development of low molecular weight manganese peroxidase mimics may achieve environmentally-safe bleaching catalysts for the industry. Herein we report the synthesis and characterization of six manganese(III) complexes 1-6, incorporating dianionic hexadentate Schiff base ligands (H 2 L 1 -H 2 L 4 ) and different anions. Complex 4, Mn 2 L 2 2 (H 2 O) 2 (DCA) 2 was crystallographically characterized. Complexes 1-4 behave as more efficient mimics of peroxidase in contrast to 5-6. We have studied the use of these complexes as catalysts for the degradation of the lignin model compound veratryl alcohol. The biomimetic catalysts were used in conjunction with chlorine-free inexpensive co-oxidants as dioxygen or hydrogen peroxide. Yields up to 30% of veratryl alcohol conversion to veratraldehyde have been achieved at room temperature in presence of air flow using 0.5% of catalyst.

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Catalytic Oxidation of Veratryl Alcohol Derivatives Using RuCo/rGO Composites

Lei

et al. 2022

Chemistry A European J

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Chemoselectively oxidizing Cα−OH to C=O has been considered as a key step for the oxidative depolymerization of lignin. In this work, we design and prepare a series of composites of RuCo alloy nanoparticles and reduced graphene oxide (RuCo/rGO) with different Ru to Co ratios and explore their catalytic activities in the oxidation of veratryl alcohol derivatives, which usually serve as the model compounds for studying lignin oxidation. It is illustrated that the Ru to Co ratio determines the morphology and average size of the RuCo alloy nanoparticles on rGO, and the overall catalytic activities of the composites. The RuCo alloy nanoparticles on rGO with Ru to Co ratios of 1 : 0 to 1.2 : 1 show a unique flower‐shaped morphology that increases the exposure of the active sites and thus promotes their contact with the substrates. The RuCo/rGO composites exhibit high catalytic activities for the oxidation of Cα−OH to aldehydes at 100 °C for 2 h. Additionally, the Co component affords the RuCo/rGO composites with magnetic properties that make the separation and recovery of the catalyst simple. Given the high catalytic performances and easy recovery, the RuCo/rGO composites would be potentially useful for the depolymerization of lignin.

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The effect of reaction conditions on the oxidation of veratryl alcohol catalyzed by cobalt salen-complexes

Cited by 32 publications

References 27 publications

Mechanistic Insights into the Oxidation of Veratryl Alcohol with Co(salen) and Oxygen in Aqueous Media: An in‐situ Spectroscopic Study

Mechanistic Insights into the Oxidation of Veratryl Alcohol with Co(salen) and Oxygen in Aqueous Media: An in‐situ Spectroscopic Study

Biomimetic Catalysts for Oxidation of Veratryl Alcohol, a Lignin Model Compound

Catalytic Oxidation of Veratryl Alcohol Derivatives Using RuCo/rGO Composites

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