The effect of the structure of the anion of an ionic liquid on the rate of reaction at a phosphorus centre

Abstract

The effects of a series of 1‐butyl‐3‐methylimidazolium based ionic liquids containing different anions on the reaction of ethanol‐d6 with diethyl chlorophosphate were investigated. Addition of each of the salts considered resulted in an increase in the rate constant; the extent of this increase was dependent on the proportion of the ionic liquid in the reaction mixture. In contrast to previous studies, the ionic liquid effects continued to change at high proportions of these salts in the reaction mixture. Temperature‐dependent kinetic analyses were used to determine the microscopic origins of the rate constant enhancement. Correlations between the activation parameters and the coordinating ability of the anion of the ionic liquid (as measured using the Kamlet‐Taft βN parameter) suggest an additional interaction to those discussed previously. Importantly, these correlations suggest the opportunity for quantification of potential ionic liquid solvent effects in these systems.

Unexpected Strong Acidity Enhancing the Effect in Protic Ionic Liquids Quantified by Equilibrium Acidity Studies: A Crucial Role of Cation Structures on Dictating the Solvation Properties

“…To the best of our knowledge, there is no systematic study on the effect of the composition of PILs on the acid–base equilibria, and the ramifications of the change of the cation and anion on the solvation properties of PILs are still not clear. Previous investigation on the acid–base equilibria or kinetic behaviors of several classical substitution reactions in ILs suggested that the cation of ILs only exhibits a minor or negligible effect, while it is the anion that plays a dominant role . In this regard, our results here are quite unexpected and clearly indicate that the structures of cations could have significant effects on the acidic dissociation equilibria in PILs.…”

A Review of Solvate Ionic Liquids: Physical Parameters and Synthetic Applications

“…The use of ionic liquids for organic transformations (Welton, 1999; Hallett and Welton, 2011), and their physical properties (Forsyth et al, 2002; Angell et al, 2007; Lee et al, 2008; Ferrara et al, 2017) have been well studied, though these solvate counterparts have a relatively low representation in the literature. Also well-established is the effect on reaction kinetics the use of ILs convey (Keaveney et al, 2017; Butler and Harper, 2018; Hawker et al, 2018), an area that has had, at the time of publishing, not been investigated in SILs.…”

Exploring Solvation Properties of Protic Ionic Liquids by Employing Solvatochromic Dyes and Molecular Dynamics Simulation Analysis

“…Characterization of solvent-solute interactions is a non-trivial task, and many different techniques have been used for this purpose. These include but are not limited to, 1 H and 13 C NMR [14], UV/vis absorption and fluorescence [15][16][17][18][19], octanol-water partition [20], chromatography [20][21][22] and analyzing the solvent effect based on standard chemical reactions [23][24][25][26][27][28]. Physical properties can also provide insight into the macroscopic polar properties of a solvent through for example, refractive index and molar refractivity [29,30], but do not provide detail on intermolecular electrostatic and polarization forces between the solute and solvent.…”