Sustainable Process for the Depolymerization/Oxidation of Softwood and Hardwood Kraft Lignins Using Hydrogen Peroxide under Ambient Conditions
| Autor: | Waleed Wafa Al Dajani, Chunbao Charles Xu, Michael Paleologou, Zaid Ahmad |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Softwood
Polyurethanes ambient temperature Pharmaceutical Science hardwood hydrogen peroxide macromolecular substances complex mixtures Lignin Article Analytical Chemistry Catalysis lcsh:QD241-441 chemistry.chemical_compound lcsh:Organic chemistry Drug Discovery Hardwood Organic chemistry Humans Physical and Theoretical Chemistry Hydrogen peroxide kraft lignin Depolymerization Hydrolysis Organic Chemistry Thermal decomposition fungi technology industry and agriculture Temperature food and beverages Wood Molecular Weight chemistry Chemistry (miscellaneous) softwood depolymerized kraft lignin Molecular Medicine Oxidation-Reduction Kraft paper |
| Zdroj: | Molecules Molecules, Vol 25, Iss 2329, p 2329 (2020) Volume 25 Issue 10 |
| ISSN: | 1420-3049 |
| Popis: | The present study demonstrated a sustainable and cost-effective approach to depolymerize/oxidize softwood (SW) and hardwood (HW) kraft lignins using concentrated hydrogen peroxide at temperatures ranging from 25 to 35 ° C, in the absence of catalysts or organic solvents. The degree of lignin depolymerization could be simply controlled by reaction time, and no further separation process was needed at the completion of the treatment. The obtained depolymerized lignin products were comprehensively characterized by GPC&ndash UV, FTIR, 31P-NMR, TGA, Py-GC/MS and elemental analysis. The weight-average molecular weights (Mw) of the depolymerized lignins obtained from SW or HW lignin at a lignin/H2O2 mass ratio of 1:1 after treatment for 120 h at room temperature (&asymp 25 ° C) were approximately 1420 Da. The contents of carboxylic acid groups in the obtained depolymerized lignins were found to significantly increase compared with those of the untreated raw lignins. Moreover, the depolymerized lignin products had lower thermal decomposition temperatures than those of the raw lignins, as expected, owing to the greatly reduced Mw. These findings represent a novel solution to lignin depolymerization for the production of chemicals that can be utilized as a bio-substitute for petroleum-based polyols in polyurethane production. |
| Databáze: | OpenAIRE |
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