Low Melting Inorganic Salts of Alkyl-, Fluoroalkyl-, Alkyl Ether-, and Fluoroalkyl Ether-Substituted Oxazolidine and Morpholine

Abstract

N-Alkyl- and N-fluoroalkyl-substituted oxazolidinium- and morpholinium-based quaternary salts and ionic liquids have been synthesized and characterized. Reactions of N-methyloxazolidine (1) or N-methylmorpholine (2) with 3-fluoropropyl bromide or iodopropane in THF at 25 °C gave the quaternary salts (3a,b, 4a,b). These salts were metathesized with various metal salts to yield the corresponding ionic liquids (5a-h, 6a-i). N-Alkoxyethyl- and N-(fluoroalkoxy)ethyl-substituted morpholines (8-11) were prepared and quaternized with methyl iodide (8a-11a). Their corresponding ionic liquids (12-18) were obtained by anion exchange and characterized. For both series of compounds, nitrate, hexafluorophosphate, perchlorate, triflate, and bis(trifluoromethanesulfonyl)amide were utilized. Most of the final products are liquids at 25 °C and are thermally stable with long liquid ranges as determined by thermal gravimetric analyses. For compounds 12, 16, and 18, thermal stabilities of ≥400 °C were observed. All the new compounds were characterized by spectroscopic and elemental analyses. Their densities and viscosities were also determined.