Difference between revisions of "Ionic liquids"

Good source for IL treatment of lignocellulosic biomass -->'''Ionic liquids''' are organic salts that are liquid at room temperature. Because they are salts, they show no volatility. Moreover, they show a high thermal stability as well. Both properties allows them to be used as green solvents and as and alternative to volatile organic compounds. These properties are useful in the pre-treatment of lignocellulosic material by dissolving the material and separating the lignin.</onlyinclude><ref name=":0">{{Cite journal|title=Ionic liquid-mediated selective extraction of lignin from wood leading to enhanced enzymatic cellulose hydrolysis|year=2009-04-01|author=Sang Hyun Lee, Thomas V. Doherty, Robert J. Linhardt, Jonathan S. Dordick|journal=Biotechnology and Bioengineering|volume=102|issue=5|page=1368–1376|doi=10.1002/bit.22179}}</ref> Lignin streams can also be dissolved to allow for further processing. <!-- I did not find examples where already separated lignin is dissolved in ionic liquids. It seems mostly the biomass is dissolved to then allow for more efficient hydrolysis (enzymatic and others)  into lignin, cellulose and other byproducts. -->

Ionic liquids are capable of dissolving lignocellulosic biomass. Examples for biomass include corn stalks, rice straw, bagasse, pine wood, and spruce wood.<ref name=":0" /> Next to lignocellulosic biomass, lignin streams can be dissolved for further processing.

Ionic liquids have been shown to dissolve lignin or cellulose, because it can decrease the crystallinity and therefore makes it more accessible for further processing. Moreover, a full dissolution of lignocellulosic biomass can be used to extract the lignin. The technology can also be combined with [[hydrolysis]] to make the cellulose available as sugars for further processing.<ref name=":0" /> Cellulose can be recovered from the solution by the addition of water, ethanol, or acetone, while the ionic liquid can be recovered by pervaporation, reverse osmosis, salting out, or ionic exchange.<ref>{{Cite journal|title=Biomass pretreatment: Fundamentals toward application|year=2011-11-01|journal=Biotechnology Advances|volume=29|issue=6|page=675–685|doi=10.1016/j.biotechadv.2011.05.005|author=Valery B. Agbor, Nazim Cicek, Richard Sparling, Alex Berlin, David B. Levin}}</ref>

The final product of the process depends on the exact combination of technologies. Generally, a large part of the lignin can be extracted from lignocellulosic material. Depending on the process properties it could also be that cellulose is more easily available for further processing.