Pretreating pine chips (Pinus sylvestris) with sodium hydroxide prior to the alkaline delignification (kraft, kraft-anthraquinone, and soda-anthraquinone) can facilitate the recovery of the carbohydrate degradation products from alkaline pulping liquors. Under suitable pretreatment conditions large amounts of carbohydrate degradation products (aliphatic acids) were formed relative to lignin. The lignin fraction was composed of comparatively low-molecular-weight fragments. Although the delignification was considerably retarded and the yield (based on wood) was decreased by 1#x2013;3, the properties of the resulting pulp were essentially maintained despite pretreatment. Finally, data are given for the composition of aliphatic acids in liquors resulting from pretreatments.
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