Development of a Continuous Clean Alkene Epoxidation Process Technology for the Production of Commercially Important Epoxide Building Blocks

烯烃（或烯烃）是一类石油衍生的碳氢化合物，是许多有机化学工业的关键原料。烯烃分子是合成各种产品（如药品、塑料、涂料、油漆、粘合剂、个人用品、家用产品和其他工业产品）的更有价值的组成部分，在将烯烃转化为分子的过程中，一个非常重要的步骤是它们的选择性氧化形成一种称为烯烃氧化物或环氧化物的新分子。将烯烃转化为环氧化物的许多商业上重要的程序使用的试剂可能非常危险，而且按现代标准，多步骤过程的环境可接受性很低。这些步骤也在所谓的间歇反应中进行，即在一个大的搅拌反应器中有效地进行，在每个批次中制备一定量的环氧化物。环氧化物的分离、回收和纯化是额外的独立过程，涉及产品的大量处理。这里提出的工作旨在开发一种将烯烃转化为环氧化物的新工艺。这种方法的基本特征已经被证明是成功的，并且正在申请专利。从本质上讲，这涉及到替代目前使用的化学物质。它使用了一种比目前使用的氧化剂本身更安全的氧化剂，并且需要使用特定的催化剂才能触发其活性，从而进一步增加了安全性。此外，该过程是连续的，而不是批量的，也就是说，生产的产品数量可以简单地通过过程允许运行的时间来控制。这为制造商与他们的客户提供了显著的业务灵活性。该过程也在称为反应精馏塔（RDC）的特殊反应器中进行。在本质上，这是一个垂直管安排与三个相连的部分。中间部分是反应器段，其中包含固体催化剂颗粒并进行化学反应，顶部和底部部分用作分离器段，在此有效地分离环氧化物产物。这种紧凑的单单元安排非常方便和高效，带来了许多优点。它大大减少了与现有工艺相关的产品的多步处理，减少了所有设备的“占地面积”和复杂性，并且大大促进了从一种烯烃原料切换到完全不同的原料的能力。从氧化剂中产生的有机副产品本身就是一种有用的化学成分，所以总的来说，所有有机化学物质的使用效率（化学家称之为“原子效率”）是非常高的。总的来说，这种新工艺为潜在用户提供了许多优势：原料灵活性、“原子效率”、生产规模的灵活性、单位成本的降低和盈利能力的提高。同样重要的是，新工艺对环氧化物生产的环境可接受性产生了重大影响。

Alkenes (or olefins) are a class of oil-derived hydrocarbons that represent key starting materials for much of the organic chemical industry. A very important step in the conversion of alkenes into molecules that are even more valuable building blocks for the synthesis of a wide variety of products (e.g. pharmaceuticals, plastics, coatings, paints, adhesives, personal products, domestic products and other industrial products) is their selective oxidation to form a new class of molecules called alkene oxides or epoxides. Many of the commercially important procedures for converting alkenes to epoxides employ reagents which are potentially very hazardous, and multi-step processes which by modern standards are of low environmental acceptability. These procedures are also carried out in so-called batch reactions i.e. effectively in a large stirred reactor, with a fixed amount of epoxide being prepared in each batch. Isolating, recovering and purification of the epoxide are additional separate processes involving considerable handling of the product.The work proposed here is aimed at developing a novel process for converting alkenes into their epoxides. The essential features of this have already been demonstrated to be successful and are in the process of being patented. Essentially this involves alternative chemistry to that currently used. It employs an oxidizing agent that is inherently more safe than the currently used agent, and one whose activity needs to be triggered by use of a particular catalyst, adding further to the safety aspects. In addition the process is a continuous rather than a batch one, i.e. the quantity of product generated can be controlled simply by how long the process is allowed to run. This offers the manufacturer significant business flexibility with their customers. The process is also carried out in a special reactor referred to as a Reactive Distillation Column (RDC). In essence this is a vertical tube arrangement with three connected sections. The middle part is a reactor section in which the solid catalyst particles are contained and the chemical reaction takes place, the top and bottom sections are used as separator sections where in effect the epoxide product is isolated. This compact single unit arrangement is extremely convenient and efficient, bringing with it many advantages. It considerably reduces the multi-step handling of the product associated with the existing processes, the 'footprint' and complexity of all the apparatus is reduced, and the ability to switch from one alkene feedstock to a completely different one is considerably facilitated. As a bonus the organic by-product from the oxidizing agent is itself a useful chemical building block and so overall the efficiency of use of all the organic chemical species (referred to by chemists as the 'atom efficiency') is very high.Overall therefore this new process provides many advantages to potential users: feedstock flexibility, 'atom efficiency', flexibility of scale of production, reduced unit costs and improved profitability. Importantly as well, the new process makes a big impact on the environmental acceptability of epoxide production.