Biomass electrochemistry: Anodic oxidation of an organo-solv lignin in the presence of nitroaromatics

Smith, Catherine Delano; Utley, James H. P.; Petrescu, Mirella; Viertler, Hans

doi:10.1007/bf01022110

Cited by 41 publications

(33 citation statements)

References 10 publications

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“…Probably the most successful electrochemical method has been the use of a sealed stainless steel cell equipped with nickel electrodes operating at several atmospheres and at [150°C. The cell and conditions are well described in a patent [9] and in the open literature [16]; essentially, lignins dissolved in aqueous sodium hydroxide are electrolysed at nickel anodes to give vanillin at [6 w/w% together with other products such as acetovanillone (2) and syringaldehyde (3). The alkaline nickel anode has been shown [21,22] to involve oxidation at the surface by a Ni(III) species.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Electro-organic reactions. Part 60[1]. The electro-oxidative conversion at laboratory scale of a lignosulfonate into vanillin in an FM01 filter press flow reactor: preparative and mechanistic aspects

Smith

Utley

Hammond³

2010

J Appl Electrochem

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The electrochemical conversion of a spruce lignosulfonate into vanillin, at nickel anodes, was explored in previously unobtainable detail. A flow reactor (FM01), in a rig that permitted considerable variation of electrolysis conditions, allowed up to 150 g to be electrolysed at up to12 A at a variety of electrode configurations. Samples taken during electrolysis gave detailed reaction profiles. The electrolyser operated at 145°C/500 kPa/3 M NaOH and yields of vanillin were similar to those obtained industrially using chemical oxidants (about 5-7% w/w). Vanillin production was favoured by low current density and low initial concentration of lignosulfonate. Vanillin, alone, was consumed in a 2.7 F process under the above conditions. Historically, yields in chemical and electrochemical conversions of lignins into vanillin do not exceed 10%; the results herein explain this apparent limit as equilibrium between formation of vanillin, its concomitant oxidative destruction and further condensation of lignins.

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Section: Introductionmentioning

confidence: 99%

“…Several attempts have been made to oxidise lignins electrochemically [15,9,16]. Oxidation of a lignin (unspecified) at a boron doped diamond anode at pH \ 11 represents a new approach, but little information is available, especially about yields of vanillin and related products [17].…”

Section: Introductionmentioning

confidence: 99%

Electro-organic reactions. Part 60[1]. The electro-oxidative conversion at laboratory scale of a lignosulfonate into vanillin in an FM01 filter press flow reactor: preparative and mechanistic aspects

Smith

Utley

Hammond³

2010

J Appl Electrochem

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“…The reaction is also important for the formation of phenolic substructures which are degraded in the initial phase under milder conditions in the case of high-yield pulping and yield vanillin. The electrooxidation of lignin for the production of vanillin was also reported (Smith et al 1989;Lalvani and Rajagopal 1993;Parpot et al 2000). But even in this case, the cleavage of non-phenolic b-O-4 substructure is a key reaction.…”

Section: Introductionmentioning

confidence: 73%

Studies on electrooxidation of lignin and lignin model compounds. Part 1: Direct electrooxidation of non-phenolic lignin model compounds

Shiraishi

Takano²,

Kamitakahara³

et al. 2012

Holzforschung

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The direct anodic oxidation of non-phenolic lignin model compounds was investigated to understand their basic behaviors. The results of cyclic voltammetry (CV) studies of monomeric model, such as 1-(4-ethoxy-3-methoxyphenyl)ethanol, are interpreted as the oxidation for C a -carbonylation did not proceed in the reaction without a catalyst, but a base promotes this reaction. Indeed, the bulk electrolyses of the monomeric lignin model compounds with 2,6-lutidine afforded the corresponding C a -carbonyl compounds in high yields (60-80%). It is suggested that deprotonation at C a -H in the ECEC mechanism (Eselectron transfer and Cschemical step) is important for C a -carbonylation. In the uncatalyzed bulk electrolysis of a b-O-4 model dimeric compound, 4-ethoxy-3-methoxyphenylglycerol-b-guaiacyl ether, the corresponding C a -carbonyl compound was not detected but as a result of C a -C b cleavage 4-O-ethylvanillin was found in 40% yield. In the electrolysis reaction in the presence of 2,6-lutidine (as a sterically hindered light base), the reaction stopped for a short time unexpectedly. These results indicate the different electrochemical behavior of simple monomeric model compounds and dimeric b-O-4 models. The conclusion is that direct electrooxidation is unsuitable for C a -carbonylation of lignin.

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“…Smith and Utley showed that a combination of nitroaromatics in an electrolysis reaction of lignin in base required lower temperatures than either reaction on its own (Smith and Utley, 1989). The disadvantage was that nitro derivatives were still present in the end product.…”

Section: Introductionmentioning

confidence: 99%

The electro-oxidation of lignin in Sappi Saiccor dissolving pulp mill effluent

Moodley¹,

Mulholland²,

Brookes³

2011

WSA

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Electro-oxidation reactions using a nickel anode were carried out on the calcium-spent liquor effluent obtained from Sappi Saiccor (formerly South African Industrial Cellulose Corporation) dissolving pulp mill as well as on lignin-and lignan-type compounds previously identified in the effluent. Voltammograms were obtained for each solution in order to identify the oxidation potentials of the compounds to be electro-oxidised. Value-added products such as vanillin and syringaldehyde were identified in the electro-oxidised reaction mixtures using gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC). Profiles of the changes in concentration of these compounds were determined as a function of time with maximum concentrations reached within the first half hour. These findings are significant in that few electro-oxidation reactions have been carried out on the effluent of a pulp mill which uses the acid bisulphite pulping process and no results have previously been reported on the electro-oxidation of syringaldehyde. This study contributes to a further understanding of the electro-oxidation of lignin and is of value to the paper and pulp industry at large. Reduction of the organic content of the effluent by electro-oxidation was shown to be possible.

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Biomass electrochemistry: Anodic oxidation of an organo-solv lignin in the presence of nitroaromatics

Cited by 41 publications

References 10 publications

Electro-organic reactions. Part 60[1]. The electro-oxidative conversion at laboratory scale of a lignosulfonate into vanillin in an FM01 filter press flow reactor: preparative and mechanistic aspects

Electro-organic reactions. Part 60[1]. The electro-oxidative conversion at laboratory scale of a lignosulfonate into vanillin in an FM01 filter press flow reactor: preparative and mechanistic aspects

Studies on electrooxidation of lignin and lignin model compounds. Part 1: Direct electrooxidation of non-phenolic lignin model compounds

The electro-oxidation of lignin in Sappi Saiccor dissolving pulp mill effluent

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