Application, Purification, and Recovery of Ionic Liquids

Olga Kuzmina,Jason Hallett

• Publisher: Elsevier
• Year: 2016
• ISBN:
  9780444633019
• Topic: Physical Sciences
• Subtopic: Fluid Mechanics

Application, Purification, and Recovery of Ionic Liquids provides a comprehensive overview of the usage of ionic liquids (IL). The book gives a description of the methods used for recovery and purification of ILs, a summary of the economic aspects of using ILs, and a review on the toxicity data of ILs.

It is written for researchers, scientists, and engineers working with ILs, their properties, and usages. The book not only describes the chemical aspects, but the economic and environmental aspects as well, making it of particular interest to professionals applying this technology.

• Chapters written by scientists in academia and researchers in industry, ensuring coverage of both the scientific fundaments and industrial applications
• A single source of information for a broad collection of recovery and purification methods
• Provides information on using ionic liquids as green solvents
• Includes economic aspects of recovery and reuse of ionic liquids

Chapter 1

Applications of Ionic Liquids

Raquel Prado

Cameron C. Weber Department of Chemistry, Imperial College London, UK

Abstract

The number of areas where ionic liquids (ILs) have been applied has increased dramatically since the beginning of the twenty-first century. In this chapter, a wide variety of IL applications are presented. For each application the role of the IL and its potential benefits are analyzed and future directions proposed. The applications outlined include the use of ILs for electrochemistry and as electrolytes; as solvents for the synthesis of organic and inorganic compounds and in the preparation of polymers; as heat transport and storage agents; within the biorefinery as solvents for the dissolution and reactivity of cellulose, hemicellulose, lignin, and wood; for analytical chemistry; and as components for tribological applications.

Keywords

ionic liquid

electrolyte

biorefinery

solvent

tribology

heat transport

chromatography

polymer

cellulose

lignin

Ionic liquids (ILs) are defined as low-melting salts (Hallett and Welton, 2011), with an arbitrary melting point of 100°C often used. Interest in these compounds has increased dramatically in recent years following the report of air- and water-stable ions in 1992, and as a result of growing safety and environmental concerns over the use of volatile solvents (Wilkes and Zaworotko, 1992). In this chapter we aim to highlight the diverse range of IL applications with the focus on the properties of ILs that render them suitable for each and a brief discussion of the current state of the art with regard to IL technology. As a result of the sheer number of areas where ILs can be applied, the highlighted applications do not aim to be exhaustive nor can the discussion of each area be fully comprehensive; however, we hope this summary illustrates the utility of this unique class of compounds.

Electrochemical applications

As ILs consist exclusively of ions, they are obvious candidates as electrolytes for a range of electrochemical applications. ILs offer a number of advantages over electrolytes that feature salts dissolved in molecular solvents. First, their low vapor pressures reduces their flammability, making them less of a fire hazard than electrolytes based on organic solvents (Fox et al., 2003, 2008). Their low vapor pressures also mean that they do not evaporate in open systems (Kar et al., 2014). Second, as they are composed solely of ions, ILs possess much greater concentrations of potential charge carriers relative to dilute salt solutions. Although this could be expected to lead to exceptionally high conductivities, this generally does not occur due to factors such as their substantial viscosity as well as the extent of ion aggregation and correlated ion motion (Hapiot and Lagrost, 2008; MacFarlane et al., 2007). Some ILs, such as the 1-alkyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([C_xC₁pyrr][NTf₂]) class, possess very large electrochemical windows in excess of 5.5 V, which increases their compatibility with a wide variety of reagents and electrochemical processes (Hapiot and La...

Table of contents

• Cover
• Title page
• Table of Contents
• Copyright
• Contributors
• Introduction
• Chapter 1: Applications of Ionic Liquids
• Chapter 2: Methods of Synthesis and Purification of Ionic Liquids
• Chapter 3: Perspective of Using ILs as “Green Solvents”
• Chapter 4: Formation of Metal–Ligand Compleхes in Ionic Liquids and Perspective of ILs Application in Purification Technologies
• Chapter 5: Methods of IL Recovery and Destruction
• Chapter 6: Economical Aspects of Ionic Liquid Application
• Subject Index