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Structure and Reactivity in Self-Organised Ionic Liquids

Cabry, Christopher Patrick (2017) Structure and Reactivity in Self-Organised Ionic Liquids. PhD thesis, University of York.

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Abstract

The research presented within this thesis aimed to contribute to the understanding of the structure of, and reactivity in, self-organised ionic liquids (ILs). This thesis comprises of three studies. The first relates to the local, short-range ordering in both pure and binary mixtures of 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imides ([CnC1im][Tf2N]). Following the synthesis of selectively deuterated materials, in order to provide the necessary contrast, small-angle neutron scattering data were collected and fit to a range of scattering models. It was found that pure ILs with short alkyl chain lengths (n = 2, 4, 6) have no alkyl chain ordering, while longer alkyl chained ILs (n = 8, 10, 12) displayed bicontinuous (percolated) structures, where one network consists of alkyl chains and the other of imidazolium head groups and [Tf2N]- anions. The bilayer separations were related directly to chain length. Neutron data were also collected for two series of binary IL mixtures, namely [C2C1im]x-1[CnC1im]x[Tf2N] and [CmC1im]x-1[C12C1im]x[Tf2N] (n = 2, 4, 6, 8, 10, 12, m = 2, 4, 6, 8). Analysis of the data revealed that several fitting models could be used and the most appropriate often depends on the composition of the mixture. The mixtures can be described as either having no alkyl chain structure, consisting of small alkyl chain aggregates, or as a bicontinuous network, depending upon the mixture, mole fraction, and alkyl chain length. The second study reports on the effect of the long-range order present in liquid-crystalline ILs (LCILs) to influence the rate of an aza-Claisen rearrangement. Ex situ 1H nuclear magnetic resonance spectroscopy indicated that a small rate change occurs through a cubic-to-columnar transition, while no change is observed through a cubic-to-isotropic transition. The third study reports on the thermal properties of fan-shaped, stilbazolium-based salts, in the search for new LCILs. Polarising optical microscopy and differential scanning calorimetry experiments determined that the stilbazolium-based salts were not liquid-crystalline.

Item Type: Thesis (PhD)
Related URLs:
Academic Units: The University of York > Chemistry (York)
Depositing User: Mr Christopher Patrick Cabry
Date Deposited: 07 Mar 2018 13:54
Last Modified: 07 Mar 2018 13:54
URI: http://etheses.whiterose.ac.uk/id/eprint/19490

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