Rethinking Calcium Fluoride Chemistry

氟是许多药品、农用化学品、麻醉剂、材料和空调制冷剂的基本元素，它们的重要特性都归功于其结构中的氟原子。例如，大约20%的上市药品和30%的农用化学品含有一个或多个氟原子，因为已知氟原子对于优化其作用方式非常重要。反过来，这导致所需的药物或农用化学品的数量减少，结果也有所改善。在材料化学和能源领域，氟化分子和塑料无处不在。一个例子是使用聚四氟乙烯（PTFE）作为锅的防粘涂层，这意味着在烹饪时需要使用更少的黄油或油。另一个例子可以在电解槽和燃料电池中找到，用于生产和“燃烧”由可再生能源产生的氢，这两者都将是可持续和无化石燃料经济的重要过程。这些装置的一个重要组成部分是由氟化物质制成的薄分离器（膜）。鉴于含氟分子的广泛使用和众多好处，生产含氟分子是一个非常大规模的过程也就不足为奇了。目前，这些高性能分子中的所有氟原子都是通过分子氟化氢（HF）引入的。HF具有严重的安全风险，因为它可以穿透皮肤，迅速引起严重烧伤，并且由于氟化物离子与骨骼中的钙反应沉淀氟化钙而有毒。HF还具有很强的腐蚀性，能与几乎所有的材料发生反应，包括玻璃、陶瓷和金属。这种危险的反应性化合物HF是由一种非常安全且不反应的材料制成的：矿物萤石（CaF2）。那么，为什么工业不直接使用这种材料来避免使用有毒的HF呢？矛盾的原因是CaF2同样的不反应性，这是由于它的溶解度差造成的。迄今为止，还没有已知的方法能够使CaF2与有机底物有效地反应以产生氟化产物。本研究的目的是改变这一状况，并开发出第一个直接使用CaF2合成氟化分子的方法。这一过程将以一种可以应用于工业的方式进行开发，目前有超过300万吨的CaF2用于生产HF，这使得这项研究具有潜在的高度影响力。因此，这项研究非常符合EPSRC的“制造未来”研究主题。

Fluorine is an essential element for many pharmaceuticals, agrochemicals, anesthetics, materials, and air-conditioning refrigerants, which owe their important properties to the fluorine atoms in their structures. For example, about 20% of marketed drugs and 30% of agrochemicals contain one or more fluorine atoms because they are known to be important for optimizing their mode of action. In turn, this leads to a lower amount of pharmaceutical or agrochemical being needed, in addition to an improved result. In the fields of materials chemistry and energy, fluorinated molecules and plastics are ubiquitous. One example is the use of polytetrafluoroethylene (PTFE) as an anti-stick coating for pans, meaning that less butter or oil needs to be used while cooking. Another example can be found in electrolyzers and fuel cells, used to produce and 'burn' hydrogen produced from renewable energy sources, both of which will be important processes in a sustainable and fossil fuel-free economy. An essential component in these devices is a thin separator (membrane) that is made from fluorinated species.Given their widespread use and numerous benefits, it is unsurprising that the production of fluorine-containing molecules is a very large-scale process. At the moment, all of the fluorine atoms in these high-performance molecules are introduced via the molecule hydrogen fluoride (HF). HF poses severe safety risks as it can penetrate the skin, can quickly cause severe burns, and is toxic as the fluoride ion reacts with calcium in your bones to precipitate calcium fluoride. HF is also very corrosive, capable of reacting with almost all materials, including glass, ceramics, and metals.This dangerous and reactive compound, HF, is made from a very safe and unreactive material: the mineral fluorspar (CaF2). So why does industry not use this material directly to avoid the use of toxic HF? The paradoxical reason is that same unreactivity of CaF2, caused by its poor solubility. No processes are known to date enabling CaF2 to react with an organic substrate to produce a fluorinated product in an efficient manner.The aim of this research is to change this situation and develop the first method(s) to use CaF2 directly in the synthesis of fluorinated molecules. This process will be developed in such a way that it can be applied in industry, where currently over 3 million tons of CaF2 is used to produce HF, making the research potentially highly impactful. Therefore, this research fits very well within EPSRC's Manufacturing the Future research theme.