Unraveling the Dissolution Mechanism of Crystalline Cellulose in Alkaline–Urea Solutions

Although it has been recently discovered that alkaline solutions containing urea can dissolve cellulose at relatively low temperatures, the molecular mechanism by which the decrystallization process takes place has not yet been elucidated. Using molecular dynamics simulations, we explore the behavior of cellulose in alkaline–urea solutions, and show that the major effects are caused by an enhancement in the concentration of both the hydroxide group as well as urea at the surface of the cellulose bundle. We compare the results obtained for the alkaline–urea solvent with comparable results obtained for ionic liquid solvents as well as other mixed solvents such as the organocat and organosolv processes.