Sustainable Manufacturing in Multiphase Continuous Reactors: Aerobic Oxidations

虽然散装化学品通常是以高效的连续过程生产的，产生的废物相对较少(E系数1-5)，但高价值的化学品(精细化学品、农用化学品、药品)通常是以批量单位生产的，产生巨大的废物(E系数约为25-100)。因此，如果连续制造技术能够适应这些行业的使用，就会有明显的商业优势。连续加工可以促进潜在危险试剂的安全操作，而这些试剂仍然可以实现低废物转化，例如通过在非常放热的过程中进行有效的热传递&最大限度地减少当地的危险材料库存。虽然大多数散装化学品的氧化可以在气相中使用分子氧连续进行，但安全考虑(放热、形成爆炸性混合物)排除了在批处理过程中使用它的可能性，特别是在精细化工制造中发现的热敏感、不稳定的基质中。这导致了两种不受欢迎的行为：a)采用昂贵、原子效率低、产生废物的化学计量氧化剂，从而对环境造成负面影响；b)倾向于通过不可避免地使用效率较低的“变通办法”来避免氧化转化。因此，很明显，氧化是一项潜在的关键使能技术。证明在有机溶剂中使用有氧氧化具有成本效益、安全和高效将具有变革性，因为工业将认真考虑广泛和不断增加的催化有机转化，而不是出于安全考虑而避免。通过“伸缩”随后的转变进一步提高效率的潜力也将通过连续的、无加工的氧化来促进。因此，该项目旨在通过开发安全的连续氧化转化来推动许多产品的生产效率的逐步变化。

While bulk chemicals are generally manufactured in efficient continuous processes, generating relatively little waste (E-factor <1-5), high value chemical products (fine chemicals, agrochemicals, pharmaceuticals) are usually manufactured in batch units, generating enormous waste (E-factor ca. 25-100). There is therefore a clear business advantage, if continuous manufacturing techniques could be adapted for use in these industries. Continuous processing can facilitate safe manipulation of potentially hazardous reagents that can nevertheless effect low-waste transformations, e.g. by efficient heat-transfer in very exothermic processes & minimising local inventory of hazardous material. Whilst most oxidations of bulk chemicals can be performed continuously using molecular oxygen in the gas phase, safety considerations (exotherm, formation of explosive mixtures) preclude its use in batch processes, particularly for thermally sensitive, involatile substrates found in fine chemical manufacture. This leads to two undesirable behaviours: a) adoption of costly, atom inefficient, waste-generating stoichiometric oxidants, with consequent negative environmental impact, and b) a tendency to avoid oxidative transformations by using inevitably less efficient 'workarounds'. It is therefore clear that oxidation is a potentially key enabling technology. The demonstration of cost-effective, safe, and efficient use of aerobic oxidation in an organic solvent would be transformative since a wide and increasing range of catalytic organic transformations would be considered seriously by industry, and not avoided due to safety concerns. The potential to drive further efficiency by 'telescoping' subsequent transformations would also be facilitated by continuous, work-up free oxidation. Thus, this project aims to instigate a step change in efficiency in the manufacture of many products by developing safe continuous oxidative transformations.