Understanding gas capacity, guest selectivity, and diffusion in porous liquids
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Porous liquids are a new class of material that could have applications in areas such as gas separation and homogeneous catalysis. Here we use a combination of measurement techniques, molecular simulations, and control experiments to advance the quantitative understanding of these liquids. In particular, we show that the cage cavities remain unoccupied in the absence of a suitable guest, and that the liquids can adsorb large quantities of gas, with gas occupancy in the cages as high as 72% and 74% for Xe and SF6, respectively. Gases can be reversibly loaded and released by using non-chemical triggers such as sonication, suggesting potential for gas separation schemes. Diffusion NMR experiments show that gases are in dynamic equilibrium between a bound and unbound state in the cage cavities, in agreement with recent simulations for related porous liquids. Comparison with gas adsorption in porous organic cage solids suggests that porous liquids have similar gas binding affinities, and that the physical properties of the cage molecule are translated into the liquid state. By contrast, some physical properties are different: for example, solid homochiral porous cages show enantioselectivity for chiral aromatic alcohols, whereas the equivalent homochiral porous liquids do not. This can be attributed to a loss of supramolecular organisation in the isotropic porous liquid.
Date Issued
2017-01-31
Date Acceptance
2017-01-12
Citation
Chemical Science, 2017, 8 (4), pp.2640-2651
ISSN
2041-6520
Publisher
Royal Society of Chemistry (RSC)
Start Page
2640
End Page
2651
Journal / Book Title
Chemical Science
Volume
8
Issue
4
Copyright Statement
© The Royal Society of Chemistry 2017. This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence (http://creativecommons.org/licenses/by-nc/3.0/).
Identifier
https://pubs.rsc.org/en/content/articlelanding/2017/SC/C6SC05196K#!divAbstract
Subjects
03 Chemical Sciences
Publication Status
Published online
Date Publish Online
2017-01-31