Enabling Oxidation Reactions on a Large Scale: Combining Electrochemistry with Flow

当一个分子被氧化时，它要么失去电子(增加它的‘氧化态’)，要么在有机化学中更常见的是，它从另一个分子(‘氧化剂’)获得一个氧原子。含氧分子是制备复杂分子的重要中间体，包括药用上感兴趣的化合物，因此对医药生产很重要。然而，由于以下原因，氧化反应往往难以大规模实现：(I)许多氧化剂要么有毒，要么是具有潜在爆炸性的热不稳定物质；(Ii)氧化反应本质上是放热的，可能涉及诱导期--这使得反应本质上是不安全的，因为热失控是不可预测的，因此很难控制。(Iii)有机溶剂中的氧化剂可能产生有机过氧化物，在一定限度内是爆炸的，也可能导致热失控反应；(4)反应可以是非选择性的，产生许多产物，分离起来可能困难且成本高昂。本项目建议通过设计一种新的设备来安全和清洁地执行这些反应来克服这些问题，主要使用电力和水来产生氧化剂。由于氧化剂是立即产生和消耗的，因此在生产过程中，活性氧化剂的有效浓度被保持在最低水平，从而消除了爆炸危险和环境暴露。我们对“无废物”反应感兴趣，这种反应产生对环境无害的副产品，如水，或以可回收和重复使用(再循环)的形式。

When a molecule is oxidised, it either loses electrons (increasing its 'oxidation state') or, more commonly in organic chemistry, it gains an oxygen atom from another molecule (the 'oxidant'). Oxygenated molecules are important intermediates for the preparation of complex molecules, including medicinally interesting compounds, and are thus important for phamaceutical production.However, oxidation reactions are often difficult to achieve on a large scale, due to the following reasons:(i) Many oxidants are either toxic, or are thermally unstable materials that are potentially explosive;(ii) Oxidation reactions are by nature exothermic and may involve induction periods - this makes a reaction inherently unsafe, as thermal runaway is unpredictable and thus difficult to control.(iii) Presence of oxidants in organic solvents may generate organic peroxides, which are explosive at a certain limit, and may also cause thermal runaway reactions;(iv) The reaction can be unselective, producing many products, which may be difficult and costly to separate.This project proposes to overcome these problems by designing a new equipment to perform these reactions safely and cleanly, using largely electricity and water to generate oxidants. As the oxidant is generated and consumed immediately, the effective concentration of the reactive oxidant is kept to a minimum during the process, thus eliminating explosive hazards and environmental exposure. We are interested in 'waste free' reactions that produces side products that are environmentally benign, such as water, or in a form that can be recovered and reused (recycled).