Earle Martyn J, Esperança José M S S, Gilea Manuela A, Lopes José N Canongia, Rebelo Luís P N, Magee Joseph W, Seddon Kenneth R, Widegren Jason A
The QUILL Centre, The Queen's University of Belfast, Stranmillis Road, Belfast BT9 5AG, UK.
Nature. 2006 Feb 16;439(7078):831-4. doi: 10.1038/nature04451.
It is widely believed that a defining characteristic of ionic liquids (or low-temperature molten salts) is that they exert no measurable vapour pressure, and hence cannot be distilled. Here we demonstrate that this is unfounded, and that many ionic liquids can be distilled at low pressure without decomposition. Ionic liquids represent matter solely composed of ions, and so are perceived as non-volatile substances. During the last decade, interest in the field of ionic liquids has burgeoned, producing a wealth of intellectual and technological challenges and opportunities for the production of new chemical and extractive processes, fuel cells and batteries, and new composite materials. Much of this potential is underpinned by their presumed involatility. This characteristic, however, can severely restrict the attainability of high purity levels for ionic liquids (when they contain poorly volatile components) in recycling schemes, as well as excluding their use in gas-phase processes. We anticipate that our demonstration that some selected families of commonly used aprotic ionic liquids can be distilled at 200-300 degrees C and low pressure, with concomitant recovery of significant amounts of pure substance, will permit these currently excluded applications to be realized.
人们普遍认为，离子液体（或低温熔盐）的一个决定性特征是它们没有可测量的蒸气压，因此不能蒸馏。在此我们证明这种观点是没有根据的，许多离子液体可以在低压下蒸馏而不分解。离子液体是仅由离子组成的物质，因此被视为非挥发性物质。在过去十年中，离子液体领域的研究迅速发展，为新的化学和萃取工艺、燃料电池和电池以及新型复合材料的生产带来了大量的知识和技术挑战与机遇。这种潜力很大程度上是基于它们假定的不挥发性。然而，这一特性在回收方案中会严重限制离子液体（当它们含有难挥发成分时）达到高纯度水平的能力，同时也排除了它们在气相过程中的应用。我们预计，我们证明一些选定的常用非质子离子液体家族可以在200 - 300摄氏度和低压下蒸馏，并伴随回收大量纯物质，这将使这些目前被排除的应用得以实现。
