Effects of Ionic Liquids on Chemical Reactions

The greatest number of publications regarding ionic liquids is on the subject of their use as solvents for synthesis. Most of these simply report the yields of closely related reactions in one or a few ionic liquids and do not attempt to understand how ionic liquids might affect these reactions in any systematic manner. In spite of this, it has been demonstrated that ionic liquids can have dramatic effects upon the products and rates of chemical reactions. This occurs through interactions between the ionic liquid ions and the starting materials and activated complexes of the reaction. This has been extensively reviewed elsewhere [1, 2,4,8,120]. 

One way in which ionic liquids have been shown to affect the outcome of a reaction is when the reaction is with one of the ions of the ionic liquid. Arenediazonium 

Dyson et al. [125] showed that the selectivities of these reactions in ionic hquids were controlled by the rate of formation of the endo adducts, with the rate of the 

Welton et al. [127] have used the linear solvation energy relationships (LSERs) approach to study the effects of ionic liquids on the kinetics of various Sfj2 nucleophilic substitution reactions. These take several forms, with different forms of charge distribution behavior (Table 2.1) [90]. 

They confirmed that the reactions in ionic liquids conformed to the Hughes-Ingold mles for the prediction of the effects of solvents on reactions, with the ionic liquids being regarded as polar solvents. The LSER approach allowed them to determine that the rates of the reactions depended upon both generalized 

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An alternative avenue to exploring the polarity of a solvent is by investigating its effect on a chemical reaction. Since the purpose of this book is to review the potential application of ionic liquids in synthesis, the effect of ionic liquids on chemical reactions has been treated separately (see Chapter 5, Section 5.1). 

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