11 Toward Industrialization of Ionic Liquids
277
viscosities will prevent the successful use of ionic liquids. In practice, these cases are
rather rare, and as with material compatibility, there are numerous options to find a
solution or workaround. For example, viscosity can be most often decreased by the
addition of sometimes small amounts of co-solvents, increasing temperature, making
eutectic mixtures of ionic liquids, changing process parameters, or process design in
order to increase mass transport. The latter can be achieved by increasing interfacial
surface area by high-shear mixing, ultrasonication, use of continuous-flow reactors,
coating of porous supports with the ionic liquid, and so on.
Only 18% of the participants mostly or rather agree, and none totally agree that
“ionic liquids disappoint in their performance and were just overestimated” (statement 12). This result again indicates that the overhyped expectations have been overcome and are understood nowadays in a historical context and from a much more
mature perspective. It is well-accepted today that ionic liquids are a key-enabling
technology for a broad range of application fields.
Are “most ionic liquids safer and greener than their molecular counterparts” (statement 13)? Although 70% of the participants agreed with this statement, approximately 50% rather agreed. There is a trend, but not a strong consent. The marketing of ionic liquids in the early days as being “green solvents” was another overgeneralization, which probably has done more harm than good to the field [57].
Meghna Dilip writes in a paper [58] that: “claims of ‘green-ness’…rest mainly on
[ionic liquids] ability to serve as non-volatile and non-flammable alternatives to traditional molecular solvents … it is increasingly apparent that no single property
other than melting point (inherent in the definition of this class of compounds) can
be used to describe the entire class of compounds …. one can no longer classify them
unequivocally as green but one can definitely not dismiss ionic liquids as un-green.”
Based on, for example, life-cycle analysis and application, a particular ionic liquid
could be called “green” in one application but determined to be “un-green” in another.
Clearly, there is a number of sustainable energy applications (e.g., energy storage,
CO 2 capture, and biomass utilization) where ionic liquids play a key-enabling role.
Many molecular fluids used every day, like gasoline fuel or engine oil, are classified
as substantially more dangerous and environmentally harmful than most ionic liquids, for example, after GHS-CLP (United Nations’ Globally Harmonized System
of Classification and Labelling of Chemicals).
“The fraction of strategic, applied research still is way too small” (statement 14) is
agreed upon by 74% of the participants. Here, 52% mostly to totally agree, and only
9% mostly or totally disagree. The point emerging from this response aligns with the
impression one gathers from visiting diverse international conferences year after year.
Most of the presentations have been, and still are, very focused on basic research.
While basic research is critically valuable and important for the field, scientists can
miss the chance to apply their work, sometimes even when the application is clearly
evident. Understandably, dialkylimidazolium cations and bistriflamide anions are
often the best candidates for studying physicochemical properties of ionic liquids,
but it is of great strategic importance to work on new ionic liquid structures (e.g.,
those that are cheaper and greener).
277
viscosities will prevent the successful use of ionic liquids. In practice, these cases are
rather rare, and as with material compatibility, there are numerous options to find a
solution or workaround. For example, viscosity can be most often decreased by the
addition of sometimes small amounts of co-solvents, increasing temperature, making
eutectic mixtures of ionic liquids, changing process parameters, or process design in
order to increase mass transport. The latter can be achieved by increasing interfacial
surface area by high-shear mixing, ultrasonication, use of continuous-flow reactors,
coating of porous supports with the ionic liquid, and so on.
Only 18% of the participants mostly or rather agree, and none totally agree that
“ionic liquids disappoint in their performance and were just overestimated” (statement 12). This result again indicates that the overhyped expectations have been overcome and are understood nowadays in a historical context and from a much more
mature perspective. It is well-accepted today that ionic liquids are a key-enabling
technology for a broad range of application fields.
Are “most ionic liquids safer and greener than their molecular counterparts” (statement 13)? Although 70% of the participants agreed with this statement, approximately 50% rather agreed. There is a trend, but not a strong consent. The marketing of ionic liquids in the early days as being “green solvents” was another overgeneralization, which probably has done more harm than good to the field [57].
Meghna Dilip writes in a paper [58] that: “claims of ‘green-ness’…rest mainly on
[ionic liquids] ability to serve as non-volatile and non-flammable alternatives to traditional molecular solvents … it is increasingly apparent that no single property
other than melting point (inherent in the definition of this class of compounds) can
be used to describe the entire class of compounds …. one can no longer classify them
unequivocally as green but one can definitely not dismiss ionic liquids as un-green.”
Based on, for example, life-cycle analysis and application, a particular ionic liquid
could be called “green” in one application but determined to be “un-green” in another.
Clearly, there is a number of sustainable energy applications (e.g., energy storage,
CO 2 capture, and biomass utilization) where ionic liquids play a key-enabling role.
Many molecular fluids used every day, like gasoline fuel or engine oil, are classified
as substantially more dangerous and environmentally harmful than most ionic liquids, for example, after GHS-CLP (United Nations’ Globally Harmonized System
of Classification and Labelling of Chemicals).
“The fraction of strategic, applied research still is way too small” (statement 14) is
agreed upon by 74% of the participants. Here, 52% mostly to totally agree, and only
9% mostly or totally disagree. The point emerging from this response aligns with the
impression one gathers from visiting diverse international conferences year after year.
Most of the presentations have been, and still are, very focused on basic research.
While basic research is critically valuable and important for the field, scientists can
miss the chance to apply their work, sometimes even when the application is clearly
evident. Understandably, dialkylimidazolium cations and bistriflamide anions are
often the best candidates for studying physicochemical properties of ionic liquids,
but it is of great strategic importance to work on new ionic liquid structures (e.g.,
those that are cheaper and greener).