Date of Award
Doctor of Philosophy (PhD)
DesMarteau, Darryl D
Smith , Dennis W
Pennington , William T
Creager , Stephen E
With their unique material and solvent properties, ionic liquids have seen an amazing, exponential increase in interest. After a brief introduction of select areas of interest for these compounds, this thesis mainly focuses on the development of novel polyfunctional ionic liquids and polymeric ionic liquids.
One of the preferred anions for ionic liquids is the bis((trifluoromethyl)sulfonyl) imide anion, first introduced by our group in 1982. It shows excellent thermal stability and the desired resonance delocalization of a negative charge for ionic liquids. A series of monofunctional, difunctional, and multi-functional bis(perfluoroalkylsufonyl)imides, along with 1,3-dialkylimidazolium cations were prepared by direct methylation of the alkylimidazole when possible, and by anion metathesis when necessary.
The resonance stabilization of the bis(perfluoroalkylsufonyl)imide anion serves two important purposes in this research. First, it provides delocalization of negative charge necessary to minimize interionic attractions in ionic liquids. Second, this same delocalization also renders the N-alkyl derivatives of the bis(perfluoroalkylsufonyl)imide anion good alkylating agents. This property is exploited in this research.
For potential electrochemical applications, polyfunctional ionic liquids were prepared to explore the properties of poly-anionic based materials. Concurrently, the effects of the organic cations, including polycations were examined. Novel ionic liquids of the following types were prepared.
In order to have a polymeric ionic liquid containing the fluoroalkyl sulfonated anion in the polymer backbone, a novel monomer of the following type was prepared.
The trifluorvinyl aryl ethers can undergo step-growth polymerization by a thermal [2 +2] cycloaddition reaction. The thermally initiated cycloaddition was possible with the ionic liquid functional group present but made processing the polymer difficult because of the low glass transition temperature.
An alternative approach to fluorinated polymeric ionic liquids is to have the anion/cation on a pendant group on a polymeric chain. For this purpose a vinyl sulfonyl fluoride monomer was prepared.
Cyclopolymerization of this monomer with tetrafluoroethylene was successfully carried out to give a novel ionomer.
Hickman, Thomas, "SYNTHESIS OF IONIC LIQUID MONOMERS USING FLUORINATED SULFONYL IMIDE ANIONS AND THE 1,3-DIALKYLIMIDAZOLIUM CATION" (2009). All Dissertations. 378.