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Conversion of native lignin to a highly phenolic functional polymer and its separation from lignocellulosics
Author(s) -
Funaoka M.,
Matsubara M.,
Seki N.,
Fukatsu S.
Publication year - 1995
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260460607
Subject(s) - lignin , chemistry , surface modification , polymer , organic chemistry , phenol , polymerization , functional polymers , aqueous two phase system , hydrolysis , aqueous solution , chemical engineering , polymer chemistry , engineering
An original reaction system (the phase separative reaction system) has been designed for derivatizing native lignins to highly phenolic, functional polymers. This system is composed of a phenol derivative and concentrated acid, which are not miscible at room temperature. The key point of the lignin functionalization process, including the phase separative system, is that lignin and carbohdrates, which are totally different in structures and reactivitie, are modified individually in the different phases: lignin is present in the organic phase and carbohydrates in the aqueous phase. Through the process, lignin was modified selectively at Cα‐positions of side chains, the most reactive sites, to give highly phenolic, light‐colored, diphenylmethane‐type materials which still retained original interunit linkages formed by the dehydrogenative polymerization during the biosynthesis. The carbohydrates were swollen, followed by partial hydrolysis and dissolution in the acid solution, resulting in the perfect decomposition of interpenetrating polymer network structures in the cell wall. Therefore, the functionalization of lignin and the separation of resulting lignin from carbohydrates were quickly achieved at room temperature, independent of wood species. This process would be a powerful tool for estimating strutures and reactivities of lignins as well as the functionalization of lignins, because of the selective structural modifications. © 1995 John Wiley & Sons, Inc.