Dissolution mechanism of N-acetylated chitotriose in urea/alkali aqueous solvents

Chitin is the second most abundant natural polysaccharides, with a repeating unit of 2-(acetylamino)-2-deoxy-d-glucose. It is regarded as a superior material for a variety of applications, including pharmaceutical, biomedical, food, textile and packaging industries. However, due to its high crystallinity and strong intra-/inter-hydrogen bonding, it is insoluble in common solvents but some acids, the later of which are poisonous, poorly degradable, corrosive, or mutagenic. Therefore, the identification of environmentally friendly solvents and comprehension of its solvation mechanism are the keys to widely applying chitin materials . Einbu et al. discovered that urea (CH4N2O) can improve chitin depolymerization, deacetylation, and alkali solution stability. Gong et al. discoverd that the dissolution power of alkalis goes in the following order: KOH>NaOH>LiOH. However, the precise mechanism of dissolution remains unknown.