An Ionic Liquid Consisting of Crown Ether-Coordinated Hydronium Cation and Amide Anion

摘要

We first report an ionic liquid (IL) that consists of hydronium (H_3O~+) ion encapsulated by 18-crown-6-ether (18C6) and an amide anion. The composition of the crown ether-coordinated hydronium amide IL was estimated to be as [H_3O~+ · 18C6][Tf_2N~-]. The presence of H_3O~+ was revealed from the characteristic bands of the hydronium ion present in the infrared spectra. The melting point of [H_3O~+·18C6][Tf_2N~-] was 68-70°C. At 70°C, the viscosity of [H_3O~+·18C6][Tf_2N~-] was 39.5 mPa s, the conductivity was 1.9 mS cm~(-1), and the density was about 1.32 g cm~(-3). These bath properties of [H_3O~+·18C6][Tf_2N~-] were similar to those of common ILs at room temperature.