Melting behavior of pyrrolidinium-based ionic liquids and their binary mixtures

Kunze M., Jeong S., Paillard E., Winter M., Passerini S

Zusammenfassung

To understand the low-temperature behavior of pyrrolidinium-based ionic liquids (ILs), ILs, including N-butyl-N-methyl pyrrolidinium (Pyr 14+) and N-methyl-N-propyl pyrrolidinium (Pyr 13+) cations and bis(fluorosulfonyl)imide (FSI -), bis(trifluoromethanesulfonyl)imide (TFSI-), bis(pentafluoroethanesulfonyl)imide (BETI-), and (trifluoromethanesulfonyl)(nonafluorobutyl-sulfonyl) imide (IM14-) anions, were investigated. Pyr14FSI, Pyr 13FSI, Pyr14TFSI, Pyr13TFSI, Pyr 14BETI, Pyr13BETI, Pyr14IM14, and Pyr13IM14 were prepared and intensively studied by means of differential scanning calorimetry (DSC). Four of these ILs (Pyr 14FSI, Pyr13FSI, Pyr14TFSI, Pyr13TFSI) were used to prepare binary mixtures, which were examined by DSC measurements. For these mixtures, reduced melting transitions and an enhanced liquidus range were detected, which represents a great advantage for low-temperature applications. In addition, it was observed that the crystallization process of the mixtures is mainly influenced by the anion. © 2010 American Chemical Society.