Long-alkyl-chain-derivatized imidazolium salts and ionic liquid crystals with tailor-made properties

Xinjiao Wang,Berthold U Melcher,Michelle Sternberg,Florian T U Kohler,Peter Wasserscheid,Karsten Meyer

doi:10.1039/c3ra47250g

Abstract

New ionic liquids and ionic liquid crystalline materials with custom-tailored properties were synthesized based on long-alkyl-chain-derivatized 1,3-dialkylimidazolium salts.

Highlights

Research interest in ionic liquids (ILs) has been growing rapidly
We previously reported the synthesis of symmetrically disubstituted imidazolium salts, namely 1,3-didodecylimidazolium tetra uoroborate [C12C12IM][BF4] and the corresponding perchlorate salt [C12C12IM][ClO4]
Attempting to improve the selectivity of catalytic reactions by creating a pre-organized, well-ordered reaction environment, we studied the use of the newly synthesized Ionic liquid crystals (ILCs), such as [C12C12IM][BF4], in “Supported Ionic Liquid Phase” (SILP) catalysis

Summary

Introduction

Research interest in ionic liquids (ILs) has been growing rapidly. This is mainly due to their unique properties, such as extremely low vapor pressures, wide liquidus ranges, high electric conductivities, wide electrochemical windows, and excellent tribological properties. Ionic liquid crystals (ILCs) are de ned as ionic species, exhibiting a liquid crystalline mesophase in a certain temperature range.[2] These materials hold great potential for catalytic applications by combining the bene cial properties of both ionic liquids and ionic liquid crystals.[3] Due to growing scienti c interest, numerous thermotropic ionic liquid crystals have been studied in recent years and are summarized in a topical review by Axenov and Laschat.[4] Amongst reported ILs and ILCs, imidazolium-based salts are some of the most frequently studied examples, due in part to the developed synthetic routes that allow for convenient derivatization.[5,6] All of these functionalized imidazolium-based ILCs have shown interesting thermal properties, imidazolium-based ILCs comprised of linear, long alkyl chains are of special interest as they tend to form ordered structures with structured ole nic solvents.

Result and discussion

Conclusion