BIBLIOS

Document type
Book chapters


Title
Accurate Measurement of Physicochemical Properties on Ionic Liquids and Molten Salts

Participants in the publication
V. M. B. Nunes (Author)
INSTITUTO POLITÉCNICO DE TOMAR
M. J. V. Lourenço (Author)
Dep. Química e Bioquímica
CQE
F. J. V. Santos (Author)
Dep. Química e Bioquímica
CQE
M. L. S. M. Lopes (Author)
Dep. Química e Bioquímica
CQE
C. A. Nieto de Castro (Author)
Dep. Química e Bioquímica
CQE

Summary
Low temperature ionic liquids with strong charge dislocation, polarity, and weak to moderate electrical conduction raise some problems regarding the accurate measurement of thermophysical properties, namely, transport properties. The methods of measurement have to be adapted to these types of liquids. This is indeed true for measuring the thermal conductivity, viscosity, electrical conductivity, and dielectric constant. For these properties, the fact that the liquid is ionic and therefore electrically conducting, and usually highly viscous, when subjected to thermal gradients, stresses and electrical fields, generates several phenomena like electric double layers, viscous heating dissipation, and the need for sensor electrical isolation that make experiments difficult to perform with high accuracy, even for temperatures around room temperature. New cells, new cable screenings, new signal analysis, and so on have to be envisaged. New reference liquids for property measurement, necessary for end-user relative methods, have to be devised and internationally accepted. An international effort, which can strengthen the first efforts to produce new and high quality property data (IUPAC Project, Ken Marsh–coordinator) has to be supported. Among others, the properties to be measured (around room temperature to temperatures up to thermal degradation) are thermal conductivity, heat capacity, viscosity, electrical conductivity, electrical permittivity, surface tension, density, and diffusion of water in ionic liquids. These will support the key data for the necessary changes in existing chemical processes or for the design of new processes, based\\\\non green or sustainable chemistry. Our research group is prepared to contribute to this effort by measuring most of these properties in selected ionic liquids. Finally, the levels of impurities in different LTILs, hydrophilic or not, have to be measured, if the data uncertainty is required to be 3% or better. The fact that the water absorption or dissolution is a time-dominated process at these low concentrations restricts the use of samples in industry for property-sensitive processes, requiring special care in production and quality control.

Editor(s)
Marcelle Gaune-Escard, Kenneth R. Seddon


Institution
FACULDADE DE CIÊNCIAS DA UNIVERSIDADE DE LISBOA

Where published
Molten Salts and Ionic Liquids: Never the Twain?

Publication Identifiers
ISBN - 9780471773924

Publisher
John Wiley & Sons, Inc.



Document Identifiers
DOI - https://doi.org/10.1002/9780470947777.ch17
URL - http://dx.doi.org/10.1002/9780470947777.ch17

Keywords
Molten Salts Ionic Liquid Property Measurement

Download