Solvent Properties of Ionic Liquids: Enabling the Assessment of Ionic Liquids for Clean, Environmentally Benign Technologies

EPA Grant Number: R831432
Title: Solvent Properties of Ionic Liquids: Enabling the Assessment of Ionic Liquids for Clean, Environmentally Benign Technologies
Investigators: Rogers, Robin D. , Holbrey, John D.
Institution: The University of Alabama
EPA Project Officer: Richards, April
Project Period: December 22, 2003 through December 21, 2006
Project Amount: $325,000
RFA: Technology for a Sustainable Environment (2003) RFA Text |  Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , Sustainable and Healthy Communities


To develop a fundamental, and comparative understanding of Ionic Liquids in order to overcome the major barriers to assessment and implementation of new, environmentally responsible technologies.

“Ionic Liquids” (ILs) are proving to be increasingly promising as viable media for “green” synthesis and separations operations and also for novel applications, where new options based upon different chemical and physical property sets of the IL materials are presented. Studies of organic reactions, such as the Diels-Alder, Suzuki, and Friedel-Crafts reactions, suggest that for many reactions IL solvents may give rise to superior results in terms of yield of reaction, product selectivity, and ease of isolation. Such findings are of potentially significant environmental and commercial importance. The range and variability in the properties between individual examples within the class of solvents that are known as ILs, are however, both challenges, and opportunities for developing new and improved processes.

Choosing the right IL for a given task should be based upon a number of factors: performance, availability, or cost, and correct selection can be vital to the overall success of any given process. Both fundamental and applied research into the properties of a broad range of ILs continue to be needed to better understand their potential in replacing traditional organic solvents and operating in the “green” paradigm. However, one of the significant current limitations in ILs research at present is that the fundamental understanding of the characteristics and solvent properties of IL systems is absent. Without this information it is not feasible to design a new process using ILs with the expectation of improving on existing technology.


The overall goals of this research are to develop and elaborate the classification of ILs in order to compare and contrast different ILs, to benchmark performance, and to discover new applications and uses of ILs. In addition to the core scientific information to be developed, this program of research will provide an educational aspect that will provide information to train researchers about the scope, potential, and pitfalls of ILs, most importantly that ILs can be utilized as much more than just non-volatile solvents.

Experimental Approach: The scientific and intellectual aspect of this proposal is to collect and evaluate data on the solvent properties of ILs in order to characterize, and classify structure-property relationships. This goal includes the following elements:

  • Development of a screening protocol to rapidly study and evaluate all current, new, and emerging commercial ILs.
  • Assessing solute partitioning in IL-organic two phase systems using Linear Free Energy Relationship analysis to develop ranking and categorization of ILs by solvent characteristics and utility in specific applications.
  • Benchmarking the performance of different, ‘representative’ ILs, identified using the screening studies above, to provide a set of ‘representative’ ILs for evaluation.
  • Application of clean syntheses of ILs in order to expand the range of materials for evaluation.
  • Provide know-how to teach about ILs and their place within the paradigm of Green Chemistry.

Expected Results:

The codification of methodologies for screening and assessing the properties and characteristics of particular ILs within the generic class of new solvents, and in relation to conventional molecular solvents, will provide a set of tools to facilitate effective and informed decisions to be rapidly made about potential use of ILs within a particular chemical or industrial process under consideration. This will permit researchers, to undertake data- rather than perception-driven research using ILs, and will facilitate selection of solvents with suitable characteristics so that in research and development progress can be effectively made.

Publications and Presentations:

Publications have been submitted on this project: View all 112 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 21 journal articles for this project

Supplemental Keywords:

chemical transport, alternative media, chemicals, toxics, green chemistry, alternatives, sustainable development, clean technologies, environmentally conscious, scientific discipline, sustainable industry/business, environmental chemistry, environmental engineering, new/innovative technologies, sustainable environment, technology for sustainable environment, volatile organic compounds (VOCs), cleaner production, environmentally benign solvents, green chemistry, green process systems, industrial innovations, industrial process, industrial separators, innovative technology, linear solvent free energy relationships, physicochemical data, room temperature ionic liquids, solvents, source reduction, RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Sustainable Industry/Business, POLLUTION PREVENTION, Sustainable Environment, cleaner production/pollution prevention, waste reduction, Environmental Chemistry, Technology for Sustainable Environment, Chemicals Management, Environmental Engineering, linear solvent free energy relationships, solvent substitutes, cleaner production, clean technology, environmentally benign solvents, green process systems, industrial process, toxicity, pollution prevention for industrial residuals, innovative technology, ionic liquids, industrial innovations, industrial separators, source reduction, green chemistry, solvents

Progress and Final Reports:

  • 2004 Progress Report
  • 2005 Progress Report
  • Final Report