I&EC 126

The standard method for the preparation of ionic liquids with alkysulfate- or alkanesulfonate-anions is based on the alkylation of organic compounds (amines, phosphines or heterocyclic bases) with dialkyl esters of sulfuric acid or alkyl esters of alkanesulfonic acids. By this procedure the alkyl group is transferred from the ester to organic base, that leads to the formation of the cation bearing of the alkyl group coming from the alkylating reagent.

Recently we developed the method [1] which gives the possibility to vary all alkyl groups in ionic liquids independently from the structure of alkylating reagents, for example:

The similar procedure was applied to the synthesis of ionic liquids with alkansulfonate or tosylate anions [2]:

This method can also be used to purify ionic liquids by removal of halide impurities.

References.

1. Patent Application, Merck KGaA (Darmstadt, Germany).

2. Patent Application, Merck KGaA (Darmstadt, Germany).