Evaluation of Ionic Liquids for Green Separations
Samuel A. Morton, III
Department of Chemical Engineering
Wednesday, August 8, 2007 3:00 pm
Ben Bandy Conference Room
UK Center for Applied Energy Research
The search for cleaner and more efficient technologies has long been a primary focus for both the industrial and academic research sector. This focus, when combined with sensitivity for the economic viability of the chemical processes under evaluation, is a fundamental tenet of the field of “Green Engineering”. To aid in the development of processes that adhere to the goals of green engineering, a framework of twelve guiding principles was proposed. These principles can be used to direct research efforts toward sustainable process technologies and prioritize the resultant alternatives based on combined economic and environmental performance.
A direction of interest to many in the green engineering field is the search for alternatives to existing separation processes that resolve the critical issues of solvent selection and energy consumption. Much of the work in green separations has focused on solvent replacement with alternatives that mitigate some issues present with traditional organic compounds (i.e. toxicity, biodegradability, volatility). A significant amount of work has been performed recently that focuses on a new class of replacement solvents known as ionic liquids. Ionic liquids are negligibly-volatile, thermally stable ionic organic compounds with a wide array of potential applications in industrial processes. Many of the useful properties of ionic liquids, such as high polarity, varying degrees of solubility in organic compounds, significant electrical conductivity, thermal stability, non-flammability, and negligible vapor pressure, support their use as replacement solvents and/or catalysts for many synthetic reactions.
Work has been performed recently that targets the use of ionic liquids as separation agents for a range of energy intensive and/or environmentally problematic separation processes. This work has been directed at separation systems that involve significant energy costs that could result in future economic viability issues. This research has not only focused on the positive elements of the use of ionic liquids, but has sought to identify and explore many of the potential challenges (cost, toxicity, chemical stability, and solubility) to their acceptance and utilization by the modern chemical industry.