IONIC CRYSTAL called 1-octadecyl-3-methylimidazolium tetrafluoroborate, as seen through polarizing filters. Textures result from the molecular formation of hydrocarbon- and ion-rich regions. Image: JOHN D. HOLBREY AND KENNETH R. SEDDON
Chemistry depends on solutions. Liquids are important because, once substances are dissolved, their molecules can readily come together to react. But many substances prove to be hard, if not impossible, to dissolve. Now a growing number of chemists believe they have discovered the correct solution--ionic liquids, peculiar combinations of salts that are liquid at room temperature. These new solvents can be tailor-made to dissolve a variety of substances, including coal, crude oil, inks, plastics, DNA and even some rocks.
Kenneth R. Seddon, chair of inorganic chemistry at Queen's University Belfast in Northern Ireland, estimates that there are, in theory, more than a trillion different ionic liquids, millions of which are extremely stable (they remain liquid over a range of about 300 degrees Celsius) and nonvolatile (they can be used over and over). They may replace toxic, flammable and polluting volatile organic solvents, such as toluene, hexane and dichloromethane, for which the worldwide annual market is about $6 billion.
This article was originally published with the title An Environmental Solution.