The Utilization of Ionic Liquid Technology for the Degradation of Biopolymers

Chitin, a polymer of N-acetyl-D-glucosamine, is the second most abundant in the world and makes up the exoskeleton of various arthropods and cell walls in various fungi.  The structure of chitin makes it insoluble in common solvents and hinders development of applications of chitin.  With the discovery that ionic liquids can dissolve chitin, the restrictions on the utilization of this unique biopolymer have been removed.

Like traditional salts, ionic liquids (ILs) are compounds composed entirely of ions.  However, unlike traditional salts, ILs are composed of bulky ions, commonly large organic cations paired with either organic or inorganic anions.  The size of the ions leads to a decreased melting point for the ILs, defining them as a compound composed entirely of ions with a melting point below 100°C.  In addition to possessing lower melting points, ILs have demonstrated unique physical and chemical properties.  Among these properties are a large liquid range, low vapor pressures, low flammability, and the ability to dissolve a variety of materials.  These properties make ILs appealing to use in various chemical processes. 

The unique property of ILs that is of interest to this research is their ability to dissolve various biopolymers, such as cellulose and chitin.^1-4  The dissolution of these biopolymers has opened up new areas of research, including efficient degradation and processing the biopolymers for new materials.  This study will investigate the effects of alkyl chain tether on catalyst behavior. This research will also observe the effects from varying the anion, temperature, and catalyst loading as well as utilizing minerals acids instead of IL catalysts.

(1)           Qin, Y.; Lu, X.; Sun, N.; Rogers, R. D. Green Chemistry 2010, 12, 968.

(2)           Xie, H.; Zhang, S.; Li, S. Green Chemistry 2006, 8, 630.

(3)           Swatloski, R. P.; Rogers, R. D.; Holbrey, J. D.  2002, p 59.

(4)           El Seoud, O. A.; Koschella, A.; Fidale, L. C.; Dorn, S.; Heinze, T. Biomacromolecules 2007, 8, 2629.