NMR Diffusion Measurements as a Simple Method to Examine Solvent-Solvent and Solvent-Solute Interactions in Mixtures of the Ionic Liquid [Bmim][N(SO2CF3)2] and Acetonitrile.
The self-diffusion coefficients of each component in mixtures of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Bmim][N(SO2CF3)2]) and acetonitrile were determined. The results suggest that the hydrodynamic boundary conditions change from "stick" to "slip" as the solvent composition transitions from "ionic liquid dissolved in acetonitrile" (χIL<0.4) to "acetonitrile dissolved in ionic liquid" (χIL>0.4). At higher χIL, the acetonitrile species are affected by "cage" and "jump" events, as the acetonitrile molecules reside nearer to the charged centre on the ions than in the "non-polar" regions. The self-diffusion coefficients of hexan-1-amine, dipropylamine, 1-hexanol and dipropylether in mixtures of [Bmim][N(SO2CF3)2] and acetonitrile were determined. In general, the nitrogen-containing solutes were found to diffuse slower than the oxygen-containing solutes; this indicates that there are greater ionic liquid-N interactions than ionic liquid-O interactions. This work demonstrates that the self-diffusion coefficients of species can provide valuable information about solvent-solvent and solvent-solute interactions in mixtures containing an ionic liquid.
School of Chemistry, University of New South Wales, UNSW, Sydney, NSW, 2052, Australia.
Sinead T
ST
Keaveney
School of Chemistry, University of New South Wales, UNSW, Sydney, NSW, 2052, Australia.
Karin S
KS
Schaffarczyk McHale
Nanoscale Organisation and Dynamics Group, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia.
James W
JW
Stranger
Nanoscale Organisation and Dynamics Group, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia.
Batchimeg
B
Ganbold
Nanoscale Organisation and Dynamics Group, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia.
William S
http://orcid.org/0000-0002-8549-4665
WS
Price
School of Chemistry, University of New South Wales, UNSW, Sydney, NSW, 2052, Australia.
Jason B
http://orcid.org/0000-0003-2722-8534
JB
Harper
acetonitrile; diffusion coefficients; ionic liquids; microscopic interactions; solvent effects