The Reactions of Lignin with Alkaline Hydrogen Peroxide. Part III. The Oxidation of Conjugated Carbonyl Structures.

Gellerstedt, Göran; Agnemo, Roland; Dale, Johannes; Daasvatn, Kari; Berg, Jan-Erik; Pilotti, Anne‐Marie

doi:10.3891/acta.chem.scand.34b-0275

Cited by 60 publications

(22 citation statements)

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“…10. Side chains attached to phenolic units, either by a conjugated double-bond or an -carbonylic group, can, during bleaching with alkaline hydrogen peroxide, form hydroquinones by side chain displacement (Gellerstedt and Agnemo 1980b). This process is shown in Fig.…”

Section: Other Reactionsmentioning

confidence: 99%

“…Also, the use of chemicals in an optional pre-treatment stage or in bleaching stages influences the distribution of chromophores and leucochromophores (precursors to colored groups) in the lignin. Examples of this phenomenon are reactions of enals and enones with sulphite during impregnation and pre-heating prior to refining Suckling 1991;Lundquist et al 2007), formation of stilbenes (Gellerstedt and Agnemo 1980a;Gellerstedt and Zhang 1992), and hydroquinones via Dakin-type reactions (from phenolic -carbonylic structures) during hydrogen peroxide bleaching (Gellerstedt and Agnemo 1980b;Lee and Sumimoto 1991;Gellerstedt and Zhang 1992), and degradation of cinnamaldehyde end groups by hydrogen peroxide (Gellerstedt and Agnemo 1980b;Gellerstedt and Zhang 1992).…”

Section: Energy Absorptionmentioning

confidence: 99%

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Review: Light-Induced Yellowing of Lignocellulosic Pulps – Mechanisms and Preventive Methods

Paulsson¹,

Parkås²

2012

BioResources

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This review will focus on recent progress regarding the mechanisms of light-induced discoloration of mechanical and chemimechanical pulps and on the proposed preventive treatments. It is evident that the mechanisms behind photoyellowing of lignin-rich pulps are complex and that several types of reaction pathways may coexist. Photoyellowing proceeds via one initial fast phase and a slower following phase. The fast phase has been ascribed to oxidation of free phenolic groups and/or hydroquinones and catechols to photoproducts of mainly quinonoid character. A multitude of reactions involving several lignin subunits are possible. Important intermediates are phenoxyl radicals, and to some extent ketyl radicals. The importance of the phenacyl aryl ether pathway might be more important than previously thought, even though the original content of such groups is low in lignin. Even though many preventive methods against photoyellowing have been suggested, no cost-efficient treatment is available to hinder photoreversion of lignincontaining paper permanently. Suggested methods for stabilization include chemical modification (etherification and esterification), coating the paper product, addition of radical scavengers, excited state quenchers, or ultraviolet absorbing compounds.

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Section: Other Reactionsmentioning

confidence: 99%

Section: Energy Absorptionmentioning

confidence: 99%

Review: Light-Induced Yellowing of Lignocellulosic Pulps – Mechanisms and Preventive Methods

Paulsson¹,

Parkås²

2012

BioResources

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“…6). The primary reaction products arising from the hydroperoxide anion can react further to acidic low molecular weight reaction products (Gierer and Imsgard 1977a,b;Chang and Gratzl 1980;Gellerstedt and Agnemo 1980), which have contribution to pH (Kalliola et al 2011). High lignin concentration in alkali-O2 oxidation may favor coupling reactions because the phenoxyl radicals are close to each other.…”

Section: Alkali-o2 Oxidationmentioning

confidence: 99%

Experiences of Kraft Lignin Functionalization by Enzymatic and Chemical Oxidation

Kalliola¹,

Asikainen²,

Talja³

et al. 2014

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Linear hydrophilic derivatives are expected to soften lignin and improve its utilization in composite applications. Oxidation by means of laccase in the presence of oxygen was employed in an attempt to functionalize commercial kraft lignin by vanillic acid-PEG ester and ether derivatives. Thielavia arenaria and Melanocarpus albomyces laccases at pH 6 and 8 were used. According to O2 consumption and the increase in molar mass, the tested laccases were active toward the lignin and the vanillic acid derivatives and also formed corresponding phenoxyl radicals. However, homogenous polymerization instead of cross-coupling and functionalization took place. As an alternative, lignin functionalization by the ester derivative by chemical oxidation under alkali-O2 conditions was also tested. Efficient lignin polymerization was observed. However, functionalization was not detected. Interestingly, a clear decrease in lignin glass transition temperature was obtained by an isolation procedure that included freeze-drying. This suggests that functionalization may not be necessary to induce the desired softening effect.

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“…They also observed that the reaction rate could be increased by the presence of heavy metal ions and high concentrations of hydrogen peroxide. The oxidation of cinnamaldehyde-type model compounds produced vanillin, which then undergoes oxidation to produce methoxyhydroquinones, and further oxidation produces carboxylic acids (Gellerstedt and Agnemo, 1980;. Studies on the hydrogen peroxide oxidation of lignin obtained from sugar cane bagasse showed the production of carboxylic acids together with some condensation products (Mancera et al, 2010) More recently, oxidative studies on lignin and lignin model compounds using biocatalysts and organometallic catalysts with oxygen and hydrogen peroxide have shown the formation of various oxidative products (Crestini et al, 2010) The aim of this study was to identify a suitable method for producing value-added products from Sappi Saiccor (situated in Durban, South Africa) dissolving pulp mill's waste stream, that could be extracted before the waste is pumped out to sea, thereby also reducing the amount of waste disposed.…”

Section: Hydrogen Peroxide Oxidation Of Lignin Type Compoundsmentioning

confidence: 99%

The chemical oxidation of lignin found in Sappi Saiccor dissolving pulp mill effluent

Moodley¹,

Mulholland²,

Brookes³

2012

WSA

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Sappi Saiccor (situated in Durban, South Africa) dissolving pulp mill effluent, produced from an acid bisulphite pulping process, uses acacia and eucalyptus hardwoods to produce a unique and different blend of lignin that has not been previously studied. The chemical oxidation of lignin found in Sappi Saiccor's effluent has been investigated using a number of different chemical oxidising agents, such as nitrobenzene, oxygen with and without the presence of a copper sulphate pentahydrate catalyst, and hydrogen peroxide. The reaction products were extracted with acid and identified using GC-MS and LC-MS techniques. Nitrobenzene is a good oxidising agent but tends to produce many toxic by-products and would not be acceptable on an industrial scale. Oxygen oxidation has previously been shown to produce aldehyde-type compounds, and in this work has produced good yields of both vanillin and syringaldehyde compared to previous oxygen oxidation reactions. Hydrogen peroxide is a strong oxidising agent that tends to over-oxidise the lignin during long reaction times.

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The Reactions of Lignin with Alkaline Hydrogen Peroxide. Part III. The Oxidation of Conjugated Carbonyl Structures.

Cited by 60 publications

References 0 publications

Review: Light-Induced Yellowing of Lignocellulosic Pulps – Mechanisms and Preventive Methods

Review: Light-Induced Yellowing of Lignocellulosic Pulps – Mechanisms and Preventive Methods

Experiences of Kraft Lignin Functionalization by Enzymatic and Chemical Oxidation

The chemical oxidation of lignin found in Sappi Saiccor dissolving pulp mill effluent

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