Progress:
A session and workshop on ionic liquids was held at the International
Conference on Chemical Thermodynamics (ICCT) in Rostock, Germany,
27 July to 2 August, 2002 (see
annex 1 - pdf 16KB). The present project objectives were finalized
at that workshop.
The selection of the reference ionic liquid was not
straightforward. Ionic liquids containing boron tetrafluoride and
phosphorus hexafluoride were found to decompose to produce HF, which
was likely one major reason for the discordant results reported in
the literature. After preliminary measurements and discussion, it
was agreed at a meeting of some of the Task Group members at the PPEPPD
Conference in Snowbird, Utah, May 2004, that the reference material
would be 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide,
[hmim][Tf2N]. (See
annex 2 - pdf 6KB). It was decided not to recommend the butyl
compound [bmim][Tf2N] because of patent concerns in the
US. The Physical and Chemical Properties Division of NIST at Boulder
agreed to purchase the starting materials and Mark Muldoon of Joan
Brennecke's group at Notre Dame agreed to prepare and characterize
up to 1 L of high purity [hmim][Tf2N].
A meeting of the Task Group was held August 17, 2004
at the ICCT, Beijing (see annex
3 - pdf 10KB). The selection of the reference material was confirmed
and the coordinators of the various property categories as well as
the participants in the measurement program were agreed upon.
GAS SOLUBILITY (Joan Brennecke,
Coordinator)
Joan Brennecke
Margarida Costa-Gomez
Gerd Maurer
Cor Peters
VLE, GAMMA INFINITY, AND EXCESS ENTHALPY (Andreas
Heintz, Coordinator)
Andreas Heintz (VLE, gamma infinity, excess enthalpy)
Trevor Letchor (gamma infinity)
DENSITY, VISCOSITY, HEAT CAPACITY (Joseph
Magee, Coordinator)
Ken Marsh (density and viscosity)
Jason Widegren (viscosity)
Don Archer (heat capacity)
Joan Brennecke
Ken Seddon
Tooru Atake (heat capacity)
Luis Paulo Rebelo (density)
Gennady Kabo (heat capacity)
Carlos Nieto de Castro (viscosity)
THERMAL CONDUCTIVITY, RELATIVE PERMITIVITY, ELECTROLYTIC
CONDUCTANCE, SURFACE TENSION, SPEED OF SOUND (Ken Marsh, Coordinator)
Ken Marsh (thermal conductivity, relative permittivity, electrolytic
conductance)
Andreas Heintz (surface tension)
Luis Paulo Rebelo (speed of sound)
Richard Perkins (thermal conductivity)
Jason Widegren (electrolytic conductance)
Carlos Nieto de Castro (thermal conductivity, relative permittivity)
LIQUID-LIQUID EQUILIBRIA, EXCESS VOLUMES (Luis
Paulo Rebelo, Coordinator)
Luis Paulo Rebelo (LLE and VE)
Andreas Heintz (LLE)
Joan Brennecke (LLE)
DECOMPOSITION TEMPERATURE, THERMAL ANALYSIS
(Ken Seddon, Coordinator)
Ken Seddon (decomposition temperature, Tg, Tm)
Joan Brennecke (decomposition temperature, Tg, Tm, Tf)
Between September and November 2004 samples with known water content,
determined by coulometric Karl Fischer titration, were distributed
from NIST to the participants in vacuum sealed Schlenk tubes. It was
agreed that measurements would be completed by July 31, 2005 and that
the results would be collected and analyzed by the coordinators and
a detailed report made to a Task Group meeting with the results reported
at a Workshop on Ionic Liquids scheduled at the next ICCT conference
(Boulder, July 30 to August 4, 2006). It was agreed that water content
would be measured by each participant before and after their measurements.
The ASTM standards for measurement of water content by both volumetric
and coulometric Karl Fischer titration were distributed.
A report on the progress of the measurement program was given at
the Thermo2005 conference in Sesimbra, Portugal, April 8 2005 (annex
4 - pdf 53KB). The status of the experimental program at the end
of May 2005 is detailed in annex
5 (pdf 14KB).
The software for submission of data to the Ionic Liquids Database
has been completed and is incorporated in the Guided Data Capture
software distributed by TRC/NIST.
See: http://trc.nist.gov/GDC.html
> Project update/announcement published in Chem.
Int.
Sep-Oct 2005
> July 2007 update - An informal meeting of a number of
members of the Task Group was held at the 1st International Congress
on Ionic Liquids (COIL) June 21, 2005, Salzburg, Austria. See minutes
as annex 6 (pdf 7KB).
During the last two years most of the planned measurements have been
completed. Many of the results have been published in the open literature
and some of the results have been submitted to NIST with the intention
that they be published in the final report. The only measurements
than have not been completed are thermal conductivity, enthalpy of
mixing, and surface tension. The hot wire technique is not suitable
for conducting liquids without major modification and researchers
using the parallel plate method did not join the project. The enthalpy
of mixing measurements requires an excessive amount of the ionic liquid
to be able to adequately cover the whole mole fraction range.
A meeting attended by Dr Marsh, Dr Magee, Dr Frenkel and Dr Chirico
was held at NIST on 28 June 2007 with the express aim of finalizing
the project, and with final draft papers preapred for submission in
December 2007.
> List of papers published or submitted and reports resulting
from this project [pdf file
- 12KB; update 2 July 2007]
Last update: 10 July 2007