Question

draw the common chemical structure of lignin and explain what types of chemical bonds in lignin molecule

Answer 1

Lignin is a crosslinked phenolic polymer mainly comprised of three constituent monomers, p-hydroxyphenyl (4-hydroxyphenyl, P), guaiacyl (4-hydroxy-3-methoxyphenyl, G), and syringyl (4-hydroxy-3,5-dimethoxyphenyl, S), arranged in a hyperbranched topology with no regular repeating structure

Lignin comprises many kinds of CeC and CeO bonds with b-O-4 aryl ether linkage being the most abundant type accounting for 30e40% of total linkages in softwood and 40e50% in hardwood lignin (Brunow & Lundquist, 2010). Other abundant bonding patterns in native lignin include b-5 phenyl coumaran, b-b 0 pinoresinol, 5-5 0 biphenyl, b-1 diaryl propane, and 4-O-5 0 diaryl ether type linkages, as well as dibenzodioxocin structures (DBDO; 5-5 0-a, b-O4 0 )