Synthesis of ionic liquid using a four-compartment configuration electrodialyzer

In this paper, a novel method was proposed to synthesize ionic liquids by using a specially designed four-compartment configuration electrodialyzer. 1-Butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4), used as a model ionic liquid, was successfully synthesized and concentrated. The products of [BMIM]BF4 could be easily obtained by using the permselectivity of ion-exchange membranes and the migration of ions under dc electric field. The structure of the products was identified with Fourier transform spectra (FTIR) and 1H NMR. It was noted that 92% yield ratio could be achieved while the purity was over 95% after operating 1 h under the voltage of 10 V.