Polymerization of lignin model compounds with formaldehyde in acidic aqueous medium

Abstract

AbstractThe reaction of formaldehyde with lignin model compounds in acidic medium was shown to give fast crosslinking of alkyl‐substituted phenolic and etherified phenolic lignin model compounds at positions meta to the aromatic hydroxy groups. This reaction differs from the reaction of formaldehyde with phenolic lignin model compounds in alkaline conditions, where the reaction with formaldehyde always occurs at positions ortho/para to the aromatic hydroxy group., The reaction of formaldehyde with lignin in acidic medium have considerable potential for the crosslinking of lignin, particularly heavily condensed alkali lignin, for use in polymeric products.