Date of Award
Doctor of Philosophy
Daniel W. Armstrong
The chiral nature of compounds contributes to their bioactivity and their various pharmaceutical/industrial uses. As a result, the Food and Drug Administration (FDA) has implemented policies for analyzing the enantiomers of chiral compounds. Gas chromatography (GC) and liquid chromatography (LC) utilizing chiral stationary phases are the two most commonly used methods to achieve direct enantiomeric separations of chiral compounds. The first part of this dissertation includes a review of direct separation of enantiomers in gas and liquid chromatography, an example of the enantiomeric separation of various racemic sulfoxides and sulfinate esters on four derivatized cyclodextrin chiral stationary phases using GC and another example of normal phase enantiomeric separations of 15 racemic analytes using an environmentally friendly solvent (ethoxynonafluorobutane) with two macrocyclic glycopeptide antibiotic chiral stationary phases and a new polymeric chiral stationary phase by LC-MS.;Ionic liquids (ILs) are low melting point (up to 100° C) salts and represent a new class of solvents with unique physico-chemical properties: negligible vapor pressure, non-flammability, high thermal stability and the ability to dissolve a variety of molecules. They have received considerable interest because of their unique properties. A detailed understanding is crucial in the design and synthesis of more efficient ILs. The second part of this thesis starts with a general review of ionic liquids. And then followed by the characterization of room temperature ionic liquids (RTILs) based on multiple solvation interactions using inverse GC. Also, a thermodynamic study was conducted to provide an understanding of ionic liquid-alkane interactions.;Chiral ionic liquids research has been much more limited and only recently has come to the forefront. The last part of this dissertation begins with a review of synthesis and applications of chiral ionic liquids. Then two examples of the applications of chiral ionic liquids were illustrated. The first example is the use of chiral ionic liquids, N,N-dimethylephedrinium-bis(trifluoromethanesulfon)imidate, as a new class of chiral stationary phases in GC. The other example showed that chiral ionic liquids can be used as "chiral induction solvents" in photoisomerization of dibenzobicyclo[2.2.2]octatrienes diacid to achieve up to 12% enantiomeric excess.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Ding, Jie, "Enantiomeric chromatographic separations and ionic liquids " (2005). Retrospective Theses and Dissertations. 1725.