Kinetic study of the catalytic oxidation of benzyl alcohols by phthalimide-N-oxyl radical electrogenerated in acetonitrile using rotating disk electrode voltammetry

“…Different electrochemical studies of benzyl alcohols oxidation by N À OH compounds in organic media have been previously reported [33,34]. In an aprotic organic solvent and in the presence of a Lewis base, the nitroxyl radical can be electrogenerated from the N À O À form of the compound and its interaction with benzyl alcohols can be easily studied.…”

Section: Catalytic Oxidation Of Benzyl Alcohols By Phenoxy Radical Elmentioning

confidence: 99%

Electrochemical Study of Phenolic Compounds as Enhancers in Laccase‐Catalyzed Oxidative Reactions

2009

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Sixteen phenolic compounds, twelve of which derived from lignin, were evaluated as potential mediators for laccaseassisted bleaching of pulp. The electrochemical behavior of these phenols, alone and in the presence of the lignin model compound veratryl alcohol, was studied by means of cyclic voltammetry. All phenolic compounds showed catalytic effect on the veratryl alcohol electrochemical oxidation. However, they could not be considered as mediators, since their oxidation products are not stable and regeneration of their reduced forms was not observed. The redox potentials of the phenolic compounds seem to have a negligible effect on their catalytic efficiency, supporting a H-abstraction oxidation mechanism. This mechanism was also confirmed by electrochemical studies of 2,4,6-trimethylphenol in acetonitrile and in the presence of benzyl alcohols.

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“…Figure 2a shows the results without a catalyst. Oxidation peak (a) at 1.8 V was found, which is thought to be the peak by several electrons withdrawing, because a shoulder peak at 1.3 V is present in CV of NHPI in 0.1 M tetrabutylammonium perchlorate (TBAP)/CH 3 CN (data not shown), and a broad peak at 1.3 V was reported in CV of NHPI in 0.1 M TEAP/CH 3 CN (Kishioka and Yamada 2005). The oxidation potentials (1.3-1.8 V) are higher than those of non-phenolic lignin model compounds (for example, 1.1 V for compound 1G, see Shiraishi et al 2011).…”

Section: Cyclic Voltammetry (Cv) Of Nhpimentioning

confidence: 99%

“…The oxidation peak current of mediators is enhanced in the presence of a substrate (Ueda et al 1987;Bourbonnais et al 1998;Gorgy et al 1998;Kishioka and Yamada 2005;González Arzola et al 2009). Figure 2b-d display the CVs of NHPI in the presence of compound 1G (2.0 eq of NHPI) and 2,6-lutidine (5.0 eq of NHPI) in 0.1 M LiClO 4 /CH 3 CN at various scan rate.…”

Section: Cyclic Voltammetry (Cv) Of Nhpimentioning

confidence: 99%

“…NHPI is known to be a powerful and common catalyst for organic oxidation reactions (Coseri 2009). However, there is only one report concerning the electro-oxidation of lignin model compound in EMS with NHPI, in which the oxidation of veratryl alcohol was studied by cyclic voltammetry (Kishioka and Yamada 2005). This paper describes the results in EMS/NHPI of non-phenolic lignin model compounds concerning the selective C a -carbonylation.…”

Section: Introductionmentioning

confidence: 98%

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Studies on electro-oxidation of lignin and lignin model compounds. Part 2: N-Hydroxyphthalimide (NHPI)-mediated indirect electro-oxidation of non-phenolic lignin model compounds

et al. 2012

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The N-hydroxyphthalimide (NHPI)-mediated indirect electro-oxidation of non-phenolic lignin model compounds has been investigated for selective C a -carbonylation of lignin. A cyclic voltammogram of NHPI in 0.1 M LiClO 4 /CH 3 CN with 2,6-lutidine interpreted that NHPI can act as a mediator in the indicated process in the range 0.5-0.8 V vs. Ag/Ag q . The corresponding C a -carbonyl compounds was obtained in high yields (85-97%) in the case of the monomer 1-(4-ethoxy-3-methoxyphenyl) ethanol in 0.1 M LiClO 4 /CH 3 CN or 0.1 M LiClO 4 /(CH 3 CN/H 2 Os7/3) with a small amount of 2,6-lutidine at 0.7 V vs. Ag/Ag q . The processing of the dimeric lignin model compound (4-ethoxy-3-methoxyphenylglycerol-b-guaiacyl ether) also gave the corresponding C a -carbonyl compound in high yield (88-92%). The reaction proceeds through hydrogen atom transfer in the NHPI-mediated electro-oxidation. On the other hand, the direct electrooxidation and indirect electro-oxidation mediated by ABTS w2,29-azinobis(3-ethylbenzothiazoline-6-sulfonate)x of the dimeric compound preferentially gave the corresponding C a -C b cleavage product in low or moderate yields (5-40%). The conclusion is that NHPI is an excellent mediator for selective C a -carbonylation of non-phenolic b-O-4 structures in lignin in electronic mediator system.

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Kinetic study of the catalytic oxidation of benzyl alcohols by phthalimide-N-oxyl radical electrogenerated in acetonitrile using rotating disk electrode voltammetry

Cited by 49 publications

References 38 publications

Thermochemistry of Proton-Coupled Electron Transfer Reagents and its Implications

Thermochemistry of Proton-Coupled Electron Transfer Reagents and its Implications

Electrochemical Study of Phenolic Compounds as Enhancers in Laccase‐Catalyzed Oxidative Reactions

Studies on electro-oxidation of lignin and lignin model compounds. Part 2: N-Hydroxyphthalimide (NHPI)-mediated indirect electro-oxidation of non-phenolic lignin model compounds

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