Ionic Liquids in-vacuo; marrying Surface Science with Solution Chemistry.

真空离子液体；

• 批准号: EP/D073014/1
• 负责人: Peter Licence
• 金额: $ 110.94万
• 依托单位: University of Nottingham
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FD073014%2F1
• 关键词: Ionic; Liquids; vacuo; marrying; Surface

The Scientific Problem: Scientific, environmental and commercial pressures are all forcing chemists to invent ever better catalytic reactions that generate the desired products with minimal waste. Biological systems achieve this goal very efficiently using chemically complex catalysts, so-called enzymes. Synthetic chemists are becoming increasingly able to design and prepare complex molecular catalysts; however, they are extremely costly in both monetary worth and environmental burden. Thus it is essential that the catalyst is conserved and not lost in the product mixture. There are several strategies for immobilising catalysts to prevent their loss and one of the more exciting new approaches is the application of ionic liquids as a selective solvent facilitating the entrapment of the catalytic species. The catalyst solution does not dissolve in the reaction mixture; hence it can be easily decanted away from the products at the end of the reaction and then reused. Although research groups throughout the world are studying ionic liquids, there is a lack of understanding about how catalysts function in ionic liquid solutions and indeed about the fundamental nature of ionic liquids as solvents. Such information is essential if catalysis is to be refined and reaction selectivity optimised. This project will address this imbalance and generate information vital to the design of better catalysts. Originality of Approach: Ionic liquids are, in general, organic based salts with melting points below room temperature. Because they are composed entirely of ions, they have an almost zero vapour pressure; they do not evaporate even under vacuum. This means that ionic liquids are difficult to ignite, unlike most of the solvents that are conventionally used for chemical synthesis. We have recognised that this lack of volatility allows ionic liquids to be used in a whole range of analytical instruments that require high vacuum for their operation. Thus ionic liquids could enable solutions and liquids to be used in high vacuum instruments for the first time, thereby allowing us to apply such techniques to probe the behaviour of catalysts in ionic liquid solutions. In addition, we can obtain an understanding of the fundamental physical chemistry of the ionic liquids themselves. Our preliminary experiments have demonstrated that this idea works in practice; we have obtained high quality X-ray photoelectron spectroscopy (XPS) data of the pure liquids as well as the liquids doped with simple metal salts. XPS provides information about the electronic structure of different elements within a compound and has sufficient sensitivity to distinguish between atoms of the same element situated in chemically distinct environments. We will extend the application of UHV spectroscopies to allow the in-situ simultaneous characterisation of REDOX active substrates by both XPS and electrochemical methods including cyclic voltammetry, providing a direct link between the electronic structure of the metal to REDOX behaviour.Application of Research: During our preliminary investigations, we noted that the conductivity of Ionic liquids changes quite dramatically as the substrate is frozen to form a solid. We observed that when the cooled surface was irradiated with a focused beam of ions (FIB) an image was written to the substrate. The image, composed of localised areas of +ve charge was found to be remarkably stable, furthermore it was noted that the image could be easily erased by one of two simple methods, i) by warming the surface to increase mobilisation that facilitated dissipation of the charge throughout the bulk, or ii) by simply exposing the frozen surface to a supply of low energy electrons from an electron flood gun. The process is rewritable and there is no detrimental effect on the substrate surface.

科学问题：科学、环境和商业压力都迫使化学家发明更好的催化反应，以最小的浪费产生所需的产品。生物系统使用化学复合催化剂，即所谓的酶，非常有效地实现了这一目标。合成化学家越来越能够设计和制备复杂的分子催化剂;然而，它们在金钱价值和环境负担方面都非常昂贵。因此，重要的是催化剂在产物混合物中被保存并且不损失。有几种固定催化剂的策略，以防止其损失和更令人兴奋的新方法之一是离子液体作为一种选择性溶剂的应用，促进催化物种的截留。催化剂溶液不溶于反应混合物中;因此在反应结束时可以容易地将其从产物中倾析出来，然后重新使用。尽管世界各地的研究小组都在研究离子液体，但对催化剂在离子液体溶液中的作用以及离子液体作为溶剂的基本性质缺乏了解。如果要改进催化和优化反应选择性，这些信息是必不可少的。该项目将解决这一不平衡问题，并产生对设计更好的催化剂至关重要的信息。方法的独创性：离子液体通常是熔点低于室温的有机盐。因为它们完全由离子组成，所以它们的蒸汽压几乎为零;即使在真空下也不会蒸发。这意味着离子液体很难点燃，不像大多数常规用于化学合成的溶剂。我们已经认识到，这种挥发性的缺乏允许离子液体用于需要高真空进行操作的整个范围的分析仪器中。因此，离子液体可以使溶液和液体首次用于高真空仪器，从而使我们能够应用这种技术来探测离子液体溶液中催化剂的行为。此外，我们还可以了解离子液体本身的基本物理化学。我们的初步实验表明，这一想法在实践中的作品，我们已经获得了高质量的纯液体以及掺杂简单的金属盐的液体的X射线光电子能谱（XPS）数据。XPS提供了关于化合物中不同元素的电子结构的信息，并且具有足够的灵敏度来区分位于化学上不同的环境中的相同元素的原子。我们将扩展超高真空光谱的应用，通过XPS和电化学方法（包括循环伏安法）对REDOX活性基质进行原位同步表征，从而在金属的电子结构与REDOX行为之间提供直接联系。在我们的初步调查中，我们注意到，当基质被冷冻形成固体时，离子液体的电导率变化相当显著。我们观察到，当冷却的表面用聚焦离子束（FIB）照射时，图像被写入到衬底上。由+ve电荷的局部区域组成的图像被发现是非常稳定的，此外，注意到图像可以通过两种简单方法中的一种容易地擦除，i）通过加热表面以增加促进电荷在整个本体中消散的活动，或ii）通过简单地将冻结的表面暴露于来自电子淹没枪的低能电子的供应。该过程是可控的，并且对衬底表面没有不利影响。

项目成果

Speciation of chloroindate(III) ionic liquids

• DOI: 10.1039/c0dt00497a
• 发表时间: 2010-01-01
• 期刊: DALTON TRANSACTIONS
• 影响因子: 4
• 作者: Apperley, David C.;Hardacre, Christopher;Villar-Garcia, Ignacio J.
• 通讯作者: Villar-Garcia, Ignacio J.

Can a Siphon Work In Vacuo?

• DOI: 10.1021/ed2001818
• 发表时间: 2011-11-01
• 期刊: JOURNAL OF CHEMICAL EDUCATION
• 影响因子: 3
• 作者: Boatwright, Adrian L.;Puttick, Simon;Licence, Peter
• 通讯作者: Licence, Peter