Introduction to Ionic Liquids

Abstract

Ionic liquids and polymerized ionic liquids possess a high application potential in synthesis, separation processes, and in processes relating to transport and storage of energy. Therefore, this introduction discusses synthetic ways to obtain ionic liquids as well as selected properties of ionic liquids. Knowledge of chemical reactions occurring during ionic liquid synthesis including purification procedures gives an insight into possible impurities, which may remain after the manufacturing process. The liquid range of ionic liquids with the glass transition temperature or the melting point as lower limit on the one hand and temperatures where weight loss is higher than 0.5 wt% during thermal treatment as possible upper limit is important for both investigation of ionic liquids as well as their application. A brief discussion of selected physical properties, such as viscosity, density, and polarity of ionic liquids should give a first impression about the broad variety of ionic liquid properties that are discussed in more detail in the following chapters. Furthermore, discussion of both polymerization of ionic liquid monomers using different polymerization mechanisms and selected properties of the polymer materials obtained will complete this introduction. The significant increase of the glass transition temperature of polymerized aprotic ionic liquids caused by polymerization of aprotic ionic liquid monomers exhibits differences in the properties between ionic liquids and polymerized ionic liquids .