Qiao, Y.; Ma, W.; Theyssen, N.; Chen, C.; Hou, Z.
Max-Planck-Institut fur Kohlenforschung &
East China University of Science and Technology
Chem. Rev. ASAP
http://pubs.acs.org/doi/pdf/10.1021/acs.chemrev.6b00652
Abstract:
Temperature-responsive ionic liquids (ILs), their fundanmental behaviors, and
catalytic applications were introduced, especially the concepts of upper critical solution
temperature (UCST) and lower critical solution temperature (LCST). It is described that,
during a catalytic reaction, they form a homogeneous mixture with the reactants and products
at reaction temperature but separate from them afterward at ambient conditions. It is shown
that this behavior offers an effective alternative approach to overcome gas/liquid−solid
interface mass transfer limitations in many catalytic transformations. It should be noted that
IL-based thermomorphic systems are rarely elaborated until now, especially in the field of
catalytic applications. The aim of this article is to provide a comprehensive review about
thermomorphic mixtures of an IL with H2O and/or organic compounds. Special focus is laid
on their temperature dependence concerning UCST and LCST behavior, including systems
with conventional ILs, metal-containing ILs, polymerized ILs, as well as the thermomorphic
behavior induced via host−guest complexation. A wide range of applications using
thermoregulated IL systems in chemical catalytic reactions as well as enzymatic catalysis
were also demonstrated in detail. The conclusion is drawn that, due to their highly attractive behavior, thermoregulated ILs have already and will find more applications, not only in catalysis but also in other areas.
catalytic applications were introduced, especially the concepts of upper critical solution
temperature (UCST) and lower critical solution temperature (LCST). It is described that,
during a catalytic reaction, they form a homogeneous mixture with the reactants and products
at reaction temperature but separate from them afterward at ambient conditions. It is shown
that this behavior offers an effective alternative approach to overcome gas/liquid−solid
interface mass transfer limitations in many catalytic transformations. It should be noted that
IL-based thermomorphic systems are rarely elaborated until now, especially in the field of
catalytic applications. The aim of this article is to provide a comprehensive review about
thermomorphic mixtures of an IL with H2O and/or organic compounds. Special focus is laid
on their temperature dependence concerning UCST and LCST behavior, including systems
with conventional ILs, metal-containing ILs, polymerized ILs, as well as the thermomorphic
behavior induced via host−guest complexation. A wide range of applications using
thermoregulated IL systems in chemical catalytic reactions as well as enzymatic catalysis
were also demonstrated in detail. The conclusion is drawn that, due to their highly attractive behavior, thermoregulated ILs have already and will find more applications, not only in catalysis but also in other areas.
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