(395ag) Large Screening of 1 Million Triazolium-Based Ionic Liquids for CO2 Capture

Fangyong Yan^1,2**, Maciej Haranczyk^2**, Hunaid Nulwala^3,4**, Jihan Kim^1,2,  Kuldeep Jariwala², Michael Lartey³, Berend Smit^1,2*, David Luebke^3*

¹ Department of Chemical and Biomolecular Engineering, UC Berkeley, Berkeley, CA

² Lawrence Berkeley National Laboratory, Berkeley, CA

³National Energy Technology Laboratory, Pittsburgh, PA

⁴ Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA. 

** contribute equally to the work

*  To whom correspondence should be addressed

Ionic liquids are organic salts existing as liquids near room temperature due to their asymmetric shape which prohibits close interaction between cations and anions. Recently, ionic liquids have attracted quite a bit of attention due to their excellent CO₂ solubility¹ and low vapor pressure².  The sheer number of possible ionic liquids, 10¹⁴ accessible structures³, presents both an opportunity and a challenge. The task of down selecting to the best ionic liquid is daunting and experimentally impossible to perform.

To identify the best candidate for CO₂ capture application we have employed a combinatorial screening methodology to examine one million 1,2,3-triazolium cations paired with the TF₂N anion. The main purpose of this study is to understand the effect of the side groups on the overall properties of these ionic liquids. In our study, we have focused on effects of aliphatic chains attached to the triazolium ring and employed combinatorial approach to generate over 1 million cations and corresponding ionic liquids. We have then sampled the resulting chemical space using diversity selection based on geometrical parameters⁴. Further, we have employed density calculations to investigate trends and structure-property relationships in these materials. We have found interesting trends in self-diffusivity, solubility, and selectivity which can be used to screen our entire library of ILs.  We will be synthesizing these ionic liquids using Cu(I) catalyzed click chemistry, and they are currently being evaluated. Our aim is to develop a rational design methodology and apply it to across all families of ionic liquids.

References

1. Cesar Cadena, Jennifer L. Anthony, Jindal K. Shah, Timothy I. Morrow, Joan F. Brennecke, and Edward J. Maginn, J. Am. Chem. Soc., 2004, 126, pp 5300–5308.
2. Lynnette A. Blanchard, Dan Hancu, Eric J. Beckman, and Joan F. Brennecke, Nature, 1999, 399, pp 28-29.
3. Alexandre Varnek, Natalia Kireeva, Igor V. Tetko, Igor I. Baskin, Vitaly P. Solov'ev, J. Chem. Inf. Model., 2007, 47, pp 1111–1122.
4. Maciej Haranczykand Maciej Gutowski,J. Comput Aided Mol Des., 2010, 24, pp 627–638.
5. Hunaid B. Nulwala ,  Chau N. Tang ,  Brian W. Kail ,  Krishnan Damodaran ,  Palwinder Kaur ,  Shan Wickramanayake , Wei Shi and David R. Luebke, Green Chem., 2011, 13, pp 3345-3349.