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

烯烃(或称烯烃)是一类油源性碳氢化合物，代表着许多有机化学工业的关键原料。在将烯烃转化为分子的过程中，非常重要的一步是将其选择性氧化，以形成一种称为烯烃氧化物或环氧化物的新分子。对于合成各种产品(如药品、塑料、涂料、涂料、粘合剂、个人产品、国内产品和其他工业产品)来说，分子是更有价值的基石。许多在商业上很重要的将烯烃转化为环氧化物的过程使用了可能非常危险的试剂，以及按现代标准来说环境可接受性较低的多步骤过程。这些过程也是在所谓的间歇反应中进行的，即在大型搅拌反应器中有效地进行，在每一批中制备固定数量的环氧化物。分离、回收和提纯环氧化物是额外的分离过程，涉及大量的产品处理。本文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。它的基本特征已经被证明是成功的，并正在申请专利。从本质上讲，这涉及到目前使用的替代化学。它使用的氧化剂本质上比目前使用的氧化剂更安全，其活性需要通过使用特定催化剂来触发，从而进一步增加了安全性。此外，该过程是连续的，而不是批处理的，即产生的产品的数量可以简单地通过允许该过程运行多长时间来控制。这为制造商与其客户提供了极大的业务灵活性。该过程也在被称为反应蒸馏塔(RDC)的特殊反应器中进行。从本质上讲，这是一种具有三个相连部分的垂直管道布置。中间部分是反应器部分，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部分，在那里实际上分离了环氧化物产品。这种紧凑的单一单元布置极其方便和高效，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骤处理，减少了所有设备的‘足迹’和复杂性，并极大地促进了从一种烯烃原料切换到完全不同的原料的能力。作为额外的好处，氧化剂产生的有机副产物本身就是一种有用的化学构件，因此所有有机化学物种的使用效率(化学家称之为原子效率)非常高。因此，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、降低单位成本和提高盈利能力。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很大影响。

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.