Stability of α-Ether type Model Compounds During Chemical Pulping Processes

Abstract In order to examine the stability of lignin-carbohydrate complexes (LCC) during alkaline chemical pulping, benzyl ether type LCC model compounds containing different non-phenolic units were synthesized and cooked under chemical pulping conditions. At least 80% of the starting substance was recovered unchanged, from soda, kraft and acid sulfite reactions indicating the benzyl ether linkage in this compound is stable during pulping. Furthermore, by blocking the reactive benzylic hydroxyl group, the cleavage of adjacent β-ether linkages in lignin moiety is retarded. Thus it is concluded that non-phenolic α-ether linkages between lignin and carbohydrates are stable under alkaline pulping conditions and may be the cause for the residual lignin to resist a complete delignification.