Physicochemical Properties of New Dicationic Ether-Functionalized Low Melting Point Ammonium Salts

Minna Kärnä; Manu Lahtinen; Pirkko-Leena Hakkarainen; Jussi Valkonen

doi:10.1071/CH09503

RESEARCH ARTICLE

Previous Contents Vol 63(7)

Physicochemical Properties of New Dicationic Ether-Functionalized Low Melting Point Ammonium Salts

Minna Kärnä ^A , Manu Lahtinen ^A ^B , Pirkko-Leena Hakkarainen ^A and Jussi Valkonen ^A

+ Author Affiliations

- Author Affiliations

^A Department of Chemistry, University of Jyväskylä, PO Box 35, 40014 University of Jyväskylä, Finland.

^B Corresponding author. Email: manu.k.lahtinen@jyu.fi

Australian Journal of Chemistry 63(7) 1122-1137 https://doi.org/10.1071/CH09503
Submitted: 18 September 2009 Accepted: 8 February 2010 Published: 15 July 2010

Abstract

Eleven new and one previously known but insufficiently characterized dicationic quaternary ammonium (QA) salts were synthesized and characterized. They contain an ethoxy ethyl group either in a side chain and/or as spacer of the diammonium cation and have bromide, hexafluorophosphate (PF₆^–), bis(trifluoromethanesulfonyl)imide (TFSI), or trifluoromethanesulfonate (TFMS) as an anion. ¹H and ¹³C techniques, mass spectrometry, and elemental analysis together with X-ray diffraction and thermoanalytical methods were used for their characterization both in the liquid and solid state. In addition, residual water content and viscosity measurements were made for the two room temperature ionic liquids (RTILs). Capillary electrophoresis was used to measure the conductivity of the RTILs. Crystal structures of four compounds were determined by X-ray single crystal diffraction, and powder diffraction was used to study the crystallinity of the solid salts and to compare the structural similarities between the single crystals and the microcrystalline bulk form. Two of the TFSI salts were liquids below room temperature, having liquid ranges of ~380 and 350°C, respectively, and seven out of 12 salts melted below 100°C. In addition, both the TFSI and PF₆ salts exhibited high thermal stabilities decomposing at about, or above 300°C. Both RTILs presented moderate viscosities at elevated temperatures. The determined physicochemical properties of the reported ILs suggest their applicability for various applications such as heat transfer fluids, high temperature synthesis, and lubricants.

Acknowledgements

The authors thank Ms. Elina Hautakangas for the elemental analyses, Mr. Reijo Kauppinen for the NMR measurements, and Ms. Mirja Lahtiperä for the ESI-TOF mass spectrometry measurements. M.K. gratefully acknowledges the financial support of the Inorganic Materials Chemistry Graduate Program and the Magnus Ehrnrooth Foundation.

References

Physicochemical Properties of New Dicationic Ether-Functionalized Low Melting Point Ammonium Salts

Abstract

Acknowledgements

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