(748e) Modeling the Dissolution of Crystalline Cellulose in Ionic Liquids

Cellulose, despite being energy-rich and in seemingly boundless supply, remains a major untapped source of raw materials, both for energy production as well as specialty manufacturing. In large part, this is a result of its natural resistance to breakup and dissolution as a result of its strong hydrogen-bond network. Though a handful of solvents, including a number of ionic liquids, have been identified as capable of dissolving cellulose, the precise attributes that enables them to function remains unclear. A better understanding of the breakup mechanisms and of cellulose-solvent interactions should aid in the search for newer and better solvents and lead to the ability to estimate dissolution times for natural cellulose fibers.

We performed MD simulations that systematically examine the breakup of small cellulose bundles in 12 different imidazolium-based ILs. We show what happens to the hydrogen bonding network of cellulose during this breakup and how the cellulose-solvent interaction energies can affect dissolution rates. Further, we propose an underlying mechanism that leads to this breakup. Using these new insights, we formulate a relatively simple kinetic model capable of describing the cellulose dissolution. We explore the main findings of this model and show how the insights obtained contribute to a fuller understanding of the dissolution process.