Affiliation:
1. Research Institute for Sustainable Humanosphere (RISH), Kyoto University , Uji 611-0011 , Japan
2. Graduate School of Bioresources , Mie University , Tsu 514-8507 , Japan
Abstract
Abstract
Dehydrogenation polymer (DHP) is widely used as a model polymer of lignin. The chemical structure of DHP is highly affected by the synthesis conditions; however, the factors affecting DHP structure are not comprehensively understood. In this study, guaiacyl DHPs were synthesized to investigate the effects of reaction scale, pH, polymerization-enzyme activity, reaction media containing organic solvent, and differences between Zutropf (ZT) and Zulauf (ZL) modes on DHP properties. The DHPs were structurally characterized by size exclusion chromatography, 1H-13C HSQC NMR, and thioacidolysis with and without Raney nickel desulfuration. In ZT mode, smaller reaction scale significantly increased β-O-4 content, and β-O-4 formation was negatively correlated with the dose of polymerization-enzyme, horseradish peroxidase. Acidic condition (pH 4.0) in succinate buffer also increased the β-O-4 content of the DHP, although the α position of the DHP was acylated by the incorporation of succinic acid. DHPs prepared at pH 9.0 had high β-1 contents and low β-5 contents, while the reaction in 20% 1,4-dioxane markedly increased the molecular weight of the DHP. A systematic approach controlling the molecular structure of DHPs would increase their value as models for native and isolated lignins.
Funder
Institute of Advanced Energy, Kyoto Univ.
Japan Society for the Promotion of Science
Research Institute for Sustainable Humanosphere, Kyoto Univ.
Cited by
1 articles.
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