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A. R. Abouelela et al.
have been proven to be stable both in air and water, and their long-term stability has
been confirmed well above the required process temperature range.
5.8 Conclusion and Lessons Learned
Ionic liquids have shown immense promise in academic research. They have at
times been condemned for the relatively early stage of the technology and lack of
past industrial application, but these facts are, as often, linked. Much development
works remain to be done, but as the technical challenges shift from fundamental
scientific understanding to process-oriented engineering exploitation, the research
priorities will be expected to evolve in kind. For biomass pretreatment, ionic liquids
have shown some unique properties; however, these should not be equated with
advantages. As a simple example, cellulose decrystallization is an unusual feature
of IL-based pretreatment but is not necessary for all applications and should not be
treated as a pre-requisite. Selecting between amorphous cellulose and pure crystalline
cellulose will depend on the application of interest and the cost of the respective
process. Aspects, such as solvent cost, are multi-dimensional; the base cost of a
solvent and its annual cost in a process are not identical—factors, such as stability,
re-use, and loading, can be used to reduce base cost factors. A literal focus on “yield”
often is counterproductive to a more realistic goal, such as unit cost.
However, a holistic view is needed to ensure a viable process option is achieved,
and end applications will require such aspects to be fully considered as proof of
principle to justify further process development.
Meanwhile, aspects, such as corrosion and energy usage on regeneration, have
largely been ignored in the literature at the expense of a focus on the high activities that
can be achieved by changing the solvent structure. Some balance is required to move
the field toward implementation, but it would be remiss to ignore the simple advances
in scientific understanding that can lead to step-changes in outlook. Ionic liquids
are significantly diverse—there is, therefore, something to be tuned by academic
synthetic chemists and industrial process engineers alike!
References
1. Beller M, Centi G, Sun L (2017) Chemistry future: priorities and opportunities from the
sustainability perspective. ChemSusChem 10:6–13. https://doi.org/10.1002/cssc.201601739
2. Fulton LM, Lynd LR, Körner A, Greene N, Tonachel LR (2015) The need for biofuels as part
of a low carbon energy future. Biofuels Bioprod Biorefining 9:476–483. https://doi.org/10.
1002/bbb.1559
3. IPCC (2015) Foreword, preface, dedication and in memoriam. Climate change 2014: mitigation of climate change. Contribution of working group III to the fifth assessment report
of the intergovernmental panel on climate change. pp. v–vi, Cambridge University Press,
Cambridge. https://doi.org/10.1017/CBO9781107415416
A. R. Abouelela et al.
have been proven to be stable both in air and water, and their long-term stability has
been confirmed well above the required process temperature range.
5.8 Conclusion and Lessons Learned
Ionic liquids have shown immense promise in academic research. They have at
times been condemned for the relatively early stage of the technology and lack of
past industrial application, but these facts are, as often, linked. Much development
works remain to be done, but as the technical challenges shift from fundamental
scientific understanding to process-oriented engineering exploitation, the research
priorities will be expected to evolve in kind. For biomass pretreatment, ionic liquids
have shown some unique properties; however, these should not be equated with
advantages. As a simple example, cellulose decrystallization is an unusual feature
of IL-based pretreatment but is not necessary for all applications and should not be
treated as a pre-requisite. Selecting between amorphous cellulose and pure crystalline
cellulose will depend on the application of interest and the cost of the respective
process. Aspects, such as solvent cost, are multi-dimensional; the base cost of a
solvent and its annual cost in a process are not identical—factors, such as stability,
re-use, and loading, can be used to reduce base cost factors. A literal focus on “yield”
often is counterproductive to a more realistic goal, such as unit cost.
However, a holistic view is needed to ensure a viable process option is achieved,
and end applications will require such aspects to be fully considered as proof of
principle to justify further process development.
Meanwhile, aspects, such as corrosion and energy usage on regeneration, have
largely been ignored in the literature at the expense of a focus on the high activities that
can be achieved by changing the solvent structure. Some balance is required to move
the field toward implementation, but it would be remiss to ignore the simple advances
in scientific understanding that can lead to step-changes in outlook. Ionic liquids
are significantly diverse—there is, therefore, something to be tuned by academic
synthetic chemists and industrial process engineers alike!
References
1. Beller M, Centi G, Sun L (2017) Chemistry future: priorities and opportunities from the
sustainability perspective. ChemSusChem 10:6–13. https://doi.org/10.1002/cssc.201601739
2. Fulton LM, Lynd LR, Körner A, Greene N, Tonachel LR (2015) The need for biofuels as part
of a low carbon energy future. Biofuels Bioprod Biorefining 9:476–483. https://doi.org/10.
1002/bbb.1559
3. IPCC (2015) Foreword, preface, dedication and in memoriam. Climate change 2014: mitigation of climate change. Contribution of working group III to the fifth assessment report
of the intergovernmental panel on climate change. pp. v–vi, Cambridge University Press,
Cambridge. https://doi.org/10.1017/CBO9781107415416