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rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2011-3-3
pubmed:abstractText
Small- and wide-angle X-ray scattering (SWAXS) has been used to investigate the effect that water has on the nanoscale structure of protic ionic liquids (PILs) along with their precursor Brønsted acids and bases. The series of PILs consisted of primary, secondary, and tertiary alkylammonium cations in conjunction with formate, nitrate, or glycolate anions. Significant differences were observed for these systems. The nanoscale aggregates present in neat protic ionic liquids were shown to be stable in size on dilution to high concentrations of water, indicating that the water is localized in the ionic region and has little effect on the nonpolar domains. The Brønsted acid-water solutions did not display nanostructure at any water concentration. Primary amine Brønsted bases formed aggregates in water, which generally displayed characteristics of poorly structured microemulsions or a form of bicontinuous phase. Exceptions were butyl- and pentylamine with high water concentrations, for which the SWAXS patterns fitted well to the Teubner-Strey model for microemulsions. Brønsted base amines containing multiple alkyl chains or hydroxyl groups did not display nanostructure at any water concentration. IR spectroscopy was used to investigate the nature of water in the various solutions. For low PIL concentrations, the water was predominately present as bulk water for PIL molar fractions less than 0.4-0.5. At high PIL concentrations, in addition to the bulk water, there was a significant proportion of perturbed water, which is water influenced in some way by the cations and anions. The molecular state of the water in the studied amines was predominately present as bulk water, with smaller contributions from perturbed water than was seen in the PILs.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Mar
pubmed:issn
1520-5207
pubmed:author
pubmed:copyrightInfo
© 2011 American Chemical Society
pubmed:issnType
Electronic
pubmed:day
10
pubmed:volume
115
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2055-66
pubmed:year
2011
pubmed:articleTitle
Nanostructured protic ionic liquids retain nanoscale features in aqueous solution while precursor Brønsted acids and bases exhibit different behavior.
pubmed:affiliation
CSIRO Materials Science and Engineering, Bag 10, Clayton, Victoria 3169, Australia.
pubmed:publicationType
Journal Article