Organic & Biomolecular Chemistry 2008-08-21

Synthesis of beta-O-4-type artificial lignin polymers and their analysis by NMR spectroscopy.

Takao Kishimoto, Yasumitsu Uraki, Makoto Ubukata

Index: Org. Biomol. Chem. 6(16) , 2982-7, (2008)

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Abstract

We describe the synthesis and NMR spectroscopic analysis of three artificial lignin polymers containing only the beta-O-4 substructure: syringyl-type homopolymer, p-hydroxyphenyl-type homopolymer and guaiacyl/syringyl-type heteropolymer. Using gel permeation chromatography, the weight-average degree of polymerization (DP(w)) of the three polymers was determined as 19.2, 38.6, and 13.9, respectively. The polymers were prepared based on the synthetic methodology of guaiacyl-type homopolymer, and were fully characterized using (1)H-, (13)C-, and (1)H-(13)C NMR spectroscopy of the acetylated and non-acetylated forms. The spectra of guaiacyl/syringyl-type heteropolymers were in good agreement with those of the beta-O-4 substructure of milled wood lignin obtained from the hardwood of Japanese white birch.