Effects of additives on dissolution of cellobiose in aqueous solvents

Cellobiose was used as a model compound for cellulose to study dissolution in aqueous systems with additives. The dissolution of cellobiose in alkali solutions is a typical exothermic enthalpy-driven process, confirming that lower temperature is beneficial for dissolution of cellulose in NaOH aqueous systems. OH plays an important role in cellobiose dissolution by forming cellobiose-OH- hydrogen-bonded complexes. The ability to form hydrogen bonds between additives and cellobiose in aqueous solutions follows the order NaOH/urea/ZnO > NaOH/urea/NaAlO2 > NaOH/urea > NaOH. Direct interactions between OH, amino groups of urea, Na+ hydrates, and cellobiose result in stable hydrogen-bonding complexes among cellobiose, OH, Na+ hydrates, and urea. Addition of ZnO or NaAlO2 can promote the dissolution power of the solvent system for cellulose. This work clarifies the interactions and dissolution mechanisms of cellulose in aqueous solution systems with additives through hydrogen-bonding interactions.