Hydroxymethylation of softwood kraft lignin and phenol with paraformaldehyde

Paananen, Hanna; Alvila, Leila; Pakkanen, Tuula T.

doi:10.1016/j.scp.2021.100376

Cited by 18 publications

(9 citation statements)

References 36 publications

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“…Then, as the active electrophilic moiety, the carbocation trapped a phenol via ortho or para -position by electrophilic reaction to form the Cα condensation product. At the same time, the γ-hydroxymethyl group was eliminated in the form of formaldehyde and the released formaldehyde was partially reacted with phenol and guaiacol to form diphenylmethanes (1, 2) . Consequently, the phenolation resulted in the increase of Ph-OH groups and the consumption of aliphatic-OH groups.…”

Section: Resultsmentioning

confidence: 99%

“…At the same time, the γ-hydroxymethyl group was eliminated in the form of formaldehyde and the released formaldehyde was partially reacted with phenol and guaiacol to form diphenylmethanes (1, 2). 59 Consequently, the phenolation resulted in the increase of Ph-OH groups and the consumption of aliphatic-OH groups. As previously reported, the substructures 3, 4, 5, 6, and 7 of P-CEL and P 3 -KL were derived from the corresponding side chains of β−O−4 and E, 42 and the substructure 8 originated from SB.…”

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confidence: 99%

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Revealing the Structural Influence on Lignin Phenolation and Its Nanoparticle Fabrication with Tunable Sizes

et al. 2022

ACS Sustainable Chem. Eng.

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Phenolation is one of the most efficient ways to improve lignin's reactivity by increasing phenolic hydroxyl (Ph-OH) contents and active sites. However, due to its complex structural nature, the lignin structure significantly impacts the phenolation and its following nanoparticle fabrication. In this study, phenolation of cellulolytic enzyme lignin (CEL) and kraft lignin (KL) of Simao pine was conducted under appropriate acidcatalyzed conditions and the resultant phenolated lignins were comprehensively characterized. The main structural difference between KL and CEL arises from the content of β-aryl ether bonds, leading to varied increments of Ph-OH contents in phenolation. Size-controlled lignin nanoparticles (LNPs) were successfully prepared from phenolated lignins with lower molecular weight, lower aliphatic-OH content, and higher level of Ph-OH groups. The average diameters and surface charges of LNPs varied from 60 to 120 nm and −30 to −55 mV, respectively, which highly depended on the phenolation degree of lignin, especially the content of Ph-OH groups. It indicates that the structural features of phenolated lignin could facilitate LNP fabrication with tunable sizes. This study reveals the structural influences on lignin phenolation and its nanoparticle fabrication, providing new insights into the size-controlled design, preparation, and application of LNPs.

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

Revealing the Structural Influence on Lignin Phenolation and Its Nanoparticle Fabrication with Tunable Sizes

et al. 2022

ACS Sustainable Chem. Eng.

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“…232 They have high bonding strength, thermal stability, and moisture resistance. 233–237 However, the high toxicity and easy glue penetration of phenolic resin adhesives cannot be ignored. 236 Lignin contains many phenolic hydroxyl groups, showing potential as a phenol substitute for the green and sustainable production of phenolic resin adhesives.…”

Section: Lignin For Adhesivesmentioning

confidence: 99%

“…236 Lignin contains many phenolic hydroxyl groups, showing potential as a phenol substitute for the green and sustainable production of phenolic resin adhesives. 237…”

Section: Lignin For Adhesivesmentioning

confidence: 99%

Lignin to value-added chemicals and advanced materials: extraction, degradation, and functionalization

Gan

Niu

et al. 2022

Green Chem.

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“…The hydroxymethylation degree of SL is better at 70 °C. Paananen et al 40 used paraformaldehyde as the source of formaldehyde and studied the hydroxymethylation reaction when the molar ratio of softwood sulfate lignin (L) to phenol (P) was 1:1 and 3:1 in the temperature range of 80−120 °C. When the molar ratio of L to P was 1:1 at 120 °C, both lignin and phenol engaged the hydroxymethylation reaction, and when L:P was 3:1, there were fewer hydroxymethylated products.…”

Section: Research Progress Of Lignin Modified Resinmentioning

confidence: 99%

Mini-Review on the Synthesis of Lignin-Based Phenolic Resin

et al. 2021

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The use of biomass in phenolic resin can not only improve performance and reduce costs but can also reduce pollution and protect the environment. Lignin is a biopolymer with a three-dimensional network structure formed by three phenylpropane units of p-hydroxyphenyl, guaiacyl, and syringyl connected by an ether bond and carbon–carbon bond, containing a large amount of phenol or an aldehyde structure unit. It is an effective way to improve the economy, protect the environment, and reproduce the resin via the synthesis of high-performance biophenolic resin polymer materials by modification or depolymerization of lignin. This review describes the latest developments in the preparation of phenolic resins by modification or depolymerization of lignin, focusing on the modification of its original functional groups by phenolization, demethylation, and hydroxymethylation, as well as chemical depolymerization methods. The properties of thermosetting or thermoplastic phenolic resins as prepared by different lignin modification methods are compared, and the future research directions for the synthesis of biomass-based phenolic resins are prospected.

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Hydroxymethylation of softwood kraft lignin and phenol with paraformaldehyde

Cited by 18 publications

References 36 publications

Revealing the Structural Influence on Lignin Phenolation and Its Nanoparticle Fabrication with Tunable Sizes

Revealing the Structural Influence on Lignin Phenolation and Its Nanoparticle Fabrication with Tunable Sizes

Lignin to value-added chemicals and advanced materials: extraction, degradation, and functionalization

Mini-Review on the Synthesis of Lignin-Based Phenolic Resin

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