Dataset Information

Nucleophilic Thiols Reductively Cleave Ether Linkages in Lignin Model Polymers and Lignin.

ABSTRACT: Lignin may serve as a renewable feedstock for the production of chemicals and fuels if mild, scalable processes for its depolymerization can be devised. The use of small organic thiols represents a bioinspired strategy to cleave the ?-O-4 bond, the most common linkage in lignin. In the present study, synthetic ?-O-4 linked polymers were treated with organic thiols, yielding up to 90?% cleaved monomer products. Lignin extracted from poplar was also treated with organic thiols resulting in molecular weight reductions as high as 65?% (Mn ) in oxidized lignin. Thiol-based cleavage of other lignin linkages was also explored in small-molecule model systems to uncover additional potential pathways by which thiols might depolymerize lignin. The success of thiol-mediated cleavage on model dimers, polymers, and biomass-derived lignin illustrates the potential utility of small redox-active molecules to penetrate complex polymer matrices for depolymerization and subsequent valorization of lignin into fuels and chemicals.

SUBMITTER: Klinger GE

PROVIDER: S-EPMC7540407 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Nucleophilic Thiols Reductively Cleave Ether Linkages in Lignin Model Polymers and Lignin.

Klinger Grace E GE Zhou Yuting Y Foote Juliet A JA Wester Abby M AM Cui Yanbin Y Alherech Manar M Stahl Shannon S SS Jackson James E JE Hegg Eric L EL

ChemSusChem 20200807 17

Lignin may serve as a renewable feedstock for the production of chemicals and fuels if mild, scalable processes for its depolymerization can be devised. The use of small organic thiols represents a bioinspired strategy to cleave the β-O-4 bond, the most common linkage in lignin. In the present study, synthetic β-O-4 linked polymers were treated with organic thiols, yielding up to 90 % cleaved monomer products. Lignin extracted from poplar was also treated with organic thiols resulting in molecul ...[more]

PMID: 32668064

Similar Datasets

Project description:The radical polymerization of acid-washed and unwashed softwood kraft lignin with [2-(methacryloyloxy) ethyl] trimethylammonium chloride (METAC) was attempted to investigate the production of lignin-based flocculants for simulated wastewater. The incorporation of METAC onto lignin resulted in a cationic charge density (2.3-3.3 meq/g), increased water solubility (89-96% in neutral pH), and increased molecular weight (70,000-210,000 g/mol) of lignin. The lignin-METAC polymers generated from acid-washed lignin had higher molecular weights than those generated from unwashed lignin. The lignin-METAC polymers showed lower resistance to thermal decomposition than unmodified lignin due to the inclusion of PolyMETAC. The unmodified acid-washed lignin samples did not significantly affect the COD of the wastewater, while the unmodified unwashed lignin samples contributed to the COD, implying that unmodified lignin was not suitable for wastewater treatment. The flocculation of wastewater with lignin-METAC led to the chemical oxygen demand (COD) reduction of 17-23% and total organic carbon (TOC) drop of 51-60%. The lignin-METAC polymer with the highest molecular weight (produced from acid-washed lignin) reached the highest COD removal, while lignin-METAC polymer with the highest charge density (produced from unwashed lignin) reached the highest TOC removal. Focused beam reflectance measurement (FBRM) studies revealed that the lignin-METAC polymer produced from acid-washed lignin with a high molecular weight generated larger and more flocs in wastewater than the lignin-METAC polymer produced from unwashed lignin. The comparison of theoretical and experimental dosages required for neutralizing the charges of wastewater demonstrated that charge neutralization was the main flocculation mechanism, although a bridging mechanism was also involved for component removals from wastewater. The use of 1 mg/L of alum along with 65 mg/L lignin-METAC in a dual coagulation-flocculation system led to higher average phosphorous (42%) and COD (44%) removals than the singular flocculation system only using 65 mg/L of lignin-METAC (with phosphorous removals of 3.4% and COD removals of 18.7%). However, lignin-METAC flocculant slightly increased the ammonia-nitrogen content in both singular flocculation and dual coagulation-flocculation systems due to the residual ammonia content of lignin-METAC. The coagulation-flocculation system determined that the use of lignin-METAC (65 mg/L) could reduce the alum dosage significantly while maintaining a similar organic content reduction of 44% for wastewater.

Dataset Information

Nucleophilic Thiols Reductively Cleave Ether Linkages in Lignin Model Polymers and Lignin.

Publications

Nucleophilic Thiols Reductively Cleave Ether Linkages in Lignin Model Polymers and Lignin.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets