Lignin: Historical, Biological, and Materials Perspectives

Abstract

In 1838, Anselme Payen discovered that treatment of wood with nitric acid and then an alkaline solution yielded a major insoluble residue that he called "cellulose," and dissolved incrustants which Schulze later designated "lignin." Following Payen's initial experiments were findings on how to selectively solubilize lignins with either sulfurous acid or alkaline solutions to yield useful cellulose fibers. Klason, Freudenberg, Nimz, Adler, Hibbert, Kratzl, Tischenko, Nakano and others conducted pioneering classical organic chemistry research that revealed much fundamental knowledge about the chemical structure of lignins. The emergence of polymer concepts provided an additional framework that advanced understanding of the physical behavior and chemical nature of lignins. Although much is known about the biosynthesis of lignin, new information is still emerging. Lignins in wood are now known to consist of a family of phenyl propane type polymers in a variety of structural units in combination with carbohydrates. Lignins are widely used as fuels in paper making processes and are sold commercially in expanding markets.