Ionic liquids are salts with low melting points capable of dissolving a variety of materials in industrial applications. Pretreatment of cellulose in an ionic liquid can disrupt the crystalline structure [1], and increase the yield for bio-ethanol production. Ionic liquids are preferred over traditional solvents because of environmental and safety considerations. For example, their negligible vapor pressure significantly reduces the risk for respiratory issues associated with breathing in harmful fumes. One of the current challenges associated with ionic liquids is accurately estimating physical properties to design new compounds because of the many possible combinations of cation/anion pairs. In this work, we classify a variety of existing ionic liquids using a support vector machine (SVM) approach for melting point using the Signature molecular descriptor. [2] Additionally, we create a quantitative structure-property relationship (QSPR) for viscosity using data for known ionic liquids.

We subsequently use our inverse-design approach with Signature coupled with the models for melting point and viscosity to identify new ionic liquids with an acceptable melting point and viscosity for cellulose pretreatment and further evaluation.

(1) Swatloski, R. P.; Spear, S. K.; Holbrey, J. D.; Rogers, R. D. Dissolution of cellose with ionic liquids. J Am Chem Soc 2002, 124, 4974-4975.

(2) Visco, D. P., Jr.; Pophale, R. S.; Rintoul, M. D.; Faulon, J. L. Developing a methodology for an inverse quantitative structure-activity relationship using the signature molecular descriptor. J. Mol. Graph. Model. 2002, 20, 429-438.