12
M. B. Shiflett et al.
Kermani applied elimination criteria on five ionic liquids that had already passed several preliminary exclusion criteria for the anion and cation. The five candidates that
made the final round were [C 2 C 1 im][CF 3 SO 3 ], [C 2 C 1 im][NTf 2 ], [P 6 6 6 14 ][NTf 2 ],
[N 1 1 1 4 ][NTf 2 ], and [N 1 8 8 8 ][NTf 2 ]. In the final analysis, [C 2 C 1 im][NTf 2 ] was the
ultimate choice over [C 2 C 1 im][CF 3 SO 3 ] due to lower water miscibility, higher
thermal stability, higher heat capacity, and a lower melting point. In addition,
[C 2 C 1 im][NTf 2 ] and [C 2 C 1 im][CF 3 SO 3 ] are available at industrial scale and both
are classified by REACH [70]. Consolidated data for hydrogen solubility are only
available for [C 2 C 1 im][NTf 2 ] [71], which is an ionic liquid of the second generation.
Currently, the database ILThermo 2.0 contains solubility data of ten binary systems
(hydrogen + ionic liquid) [72] as will be highlighted in the next section.
1.5 IUPAC Projects with Impact on Commercial
Applications
A historical perspective by Joe Magee, (NIST, Boulder, Colorado, U.S.A.).
1.5.1 IUPAC Project 2002-005-1-100 Thermodynamics
of Ionic Liquids, Ionic Liquid Mixtures,
and the Development of Standardized Systems
The utilization of ionic liquids in both chemical research and in industrial chemistry
requires a systematic study of their thermodynamic and thermophysical properties
that are required for chemical process design. For these reasons, Professor Kenneth
(Ken) Marsh (formerly with the University of Canterbury, New Zealand) formed an
international task group under the auspices of IUPAC with the goal of providing
reliable data for a range of properties that could be used to check methods and
calibrations for experimental instruments. Professor Marsh called the first task group
meeting in Rostock, Germany, at the IUPAC International Conference on Chemical
Thermodynamics [73]. Professor Marsh announced the intentions of this project at a
workshop co-chaired with Dr. Joe Magee (NIST). Choosing a good reference material
was paramount to this work. It would have to have a low melting point, a low viscosity,
hydrophobic properties, be unrestricted by patents, and readily synthesized by users.
After lengthy deliberations, the task group chose the reference material 1-hexyl3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([C 6 C 1 im][NTf 2 ]). A total
of one liter of reference material was synthesized, purified, and characterized by
Dr. Mark Muldoon of Professor Joan Brennecke’s laboratory at the University of
Notre Dame, Indiana. That sample was shipped to Dr. Magee at NIST, where it
was further dried and characterized by
1 H and
19 F NMR spectroscopy and Karl
Fischer titration. Dr. Jason Widegren (NIST) divided the sample into aliquots that
M. B. Shiflett et al.
Kermani applied elimination criteria on five ionic liquids that had already passed several preliminary exclusion criteria for the anion and cation. The five candidates that
made the final round were [C 2 C 1 im][CF 3 SO 3 ], [C 2 C 1 im][NTf 2 ], [P 6 6 6 14 ][NTf 2 ],
[N 1 1 1 4 ][NTf 2 ], and [N 1 8 8 8 ][NTf 2 ]. In the final analysis, [C 2 C 1 im][NTf 2 ] was the
ultimate choice over [C 2 C 1 im][CF 3 SO 3 ] due to lower water miscibility, higher
thermal stability, higher heat capacity, and a lower melting point. In addition,
[C 2 C 1 im][NTf 2 ] and [C 2 C 1 im][CF 3 SO 3 ] are available at industrial scale and both
are classified by REACH [70]. Consolidated data for hydrogen solubility are only
available for [C 2 C 1 im][NTf 2 ] [71], which is an ionic liquid of the second generation.
Currently, the database ILThermo 2.0 contains solubility data of ten binary systems
(hydrogen + ionic liquid) [72] as will be highlighted in the next section.
1.5 IUPAC Projects with Impact on Commercial
Applications
A historical perspective by Joe Magee, (NIST, Boulder, Colorado, U.S.A.).
1.5.1 IUPAC Project 2002-005-1-100 Thermodynamics
of Ionic Liquids, Ionic Liquid Mixtures,
and the Development of Standardized Systems
The utilization of ionic liquids in both chemical research and in industrial chemistry
requires a systematic study of their thermodynamic and thermophysical properties
that are required for chemical process design. For these reasons, Professor Kenneth
(Ken) Marsh (formerly with the University of Canterbury, New Zealand) formed an
international task group under the auspices of IUPAC with the goal of providing
reliable data for a range of properties that could be used to check methods and
calibrations for experimental instruments. Professor Marsh called the first task group
meeting in Rostock, Germany, at the IUPAC International Conference on Chemical
Thermodynamics [73]. Professor Marsh announced the intentions of this project at a
workshop co-chaired with Dr. Joe Magee (NIST). Choosing a good reference material
was paramount to this work. It would have to have a low melting point, a low viscosity,
hydrophobic properties, be unrestricted by patents, and readily synthesized by users.
After lengthy deliberations, the task group chose the reference material 1-hexyl3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([C 6 C 1 im][NTf 2 ]). A total
of one liter of reference material was synthesized, purified, and characterized by
Dr. Mark Muldoon of Professor Joan Brennecke’s laboratory at the University of
Notre Dame, Indiana. That sample was shipped to Dr. Magee at NIST, where it
was further dried and characterized by
1 H and
19 F NMR spectroscopy and Karl
Fischer titration. Dr. Jason Widegren (NIST) divided the sample into aliquots that