Anomalous diffusion of water in [BMIM][TFSI] room-temperature ionic liquid.
We have studied the self-diffusion properties of butyl-methyl-imidazolium bis(trifluoromethylsulfonyl)-imide ([BMIM][TFSI]) + water system. The self-diffusion coefficients of cations, anions, and water molecules were determined by pulsed field gradient NMR. These measures were performed with increased water quantity up to saturation (from 0.3 to 30 mol %). Unexpected variations have been observed. The self-diffusion coefficient of every species increases with the quantity of water but not in the same order of magnitude. Whereas very similar evolutions are observed for the anion and cation, the increase is 25 times greater for water molecules. We interpret our data by the existence of phase separation at microscopic scale.
Rollet
Anne-Laure
AL
Centre de Recherche sur les Matériaux à Haute Température (CRMHT) - CNRS 1D avenue de la Recherche Scientifique, 45071, Orléans Cedex 2, France. rollet@cnrs-orleans.fr
Porion
Patrice
P
Vaultier
Michel
M
Billard
Isabelle
I
Deschamps
Michael
M
Bessada
Catherine
C
Jouvensal
Laurence
L
D004058:Diffusion; D007093:Imidazoles / Q000737:chemistry*; D007094:Imides / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D015394:Molecular Structure; D013696:Temperature; D014867:Water / Q000737:chemistry*
D007093:Imidazoles; D007094:Imides; D052578:Ionic Liquids; C524832:butyl-methyl-imidazolium bis(trifluoromethylsulfonyl)-imide; D014867:Water