Rate-Determining Steps of Cooking Reactions in Birchwood Digestion with Acid Sulfite Liquors

Abstract

Cooking data from earlier digestions of birchwood by liquors of SO₂-MgSO₄ bicomponents and Mg base sulfite were analysed by the same basic heterogeneous kinetics as spruce-wood digestion previuosly reported to estimate rate-determining steps of their reactions of delignification and dissolution of carbohydrates.
Quite different progress modes and rates of the cooking reactions were observed between the two liquor systems. These can be reasonably accounted for by different porous structure development in the wood cell wall relating to different digestive powers between the both liquors.
When the results of birchwood digestion were compared with those of the previous sprucewood digestion, some interesting informations on their characteristics of digestive behavior were derived.