Heterobimetallic Catalysts for Carbon Dioxide and Propene Oxide Copolymerization: Exploiting and Understanding Synergy

二氧化碳和环氧丙烷共聚的异双金属催化剂：利用和理解协同作用

• 批准号: 2580967
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2580967
• 关键词: Heterobimetallic; Catalysts; Carbon; Dioxide; Propene

Plastics are found everywhere in our daily lives. We use them in everything from food packaging, plastic bags, and plastic bottles to foams in mattresses or house insulation. Plastics are made of polymers, which are long chains made up of many building blocks ("monomers"). To form a polymer the monomers are linked up one after the other, like beads on a string. Depending on the identity of the monomer, the properties of the resulting polymer, and therefore the plastic, vary drastically. Currently, nearly all of the monomers that are used in the production of polymers are derived from crude oil. This means that we are reliant on fossil fuels to make polymers and that there are considerable carbon emissions associated with polymer production. In order to address the climate crisis, it is important to move away from the crude oil derived monomers. One approach to do this is to replace half of the monomers used to form a polymer with carbon dioxide.Carbon dioxide is an attractive monomer because it is non-toxic, renewable, and inexpensive, as it is produced as a waste product in many industrial processes. Using carbon dioxide as monomer reduces the carbon footprint of polymers in two ways. Firstly, in carbon dioxide containing polymers, only half of the monomers used are derived from crude oil. This means that less monomers need to be made and less carbon dioxide is released into the atmosphere during monomer production. Secondly, each molecule of carbon dioxide used as a monomer would otherwise be emitted into the atmosphere, but is "saved" from being emitted by incorporation into the polymer.It is, however, very difficult to incorporate carbon dioxide into polymers, because it is unreactive. To overcome this, a chemical, known as a catalyst can be used. The catalyst speeds up the incorporation reaction of carbon dioxide into the polymer, without being used up in the process. The catalyst can also be used to control the order in which the carbon dioxide and the other monomer are linked up. This is important as not only the type of monomer used, but also the order in which they are lined up, will determine the properties of the plastic.Catalysts for the incorporation of carbon dioxide into polymers have been developed since the late 1960s. The catalysts developed so far either contain toxic components, are very difficult to make, or need high temperatures or very pure carbon dioxide. This makes them expensive and inconvenient to use at a large industrial scale.Recently a new type of catalyst, that contains non-toxic and earth abundant metals, such as sodium, potassium or magnesium, was discovered. This is the first example of a catalyst that uses these types of metals. So far, the understanding of how exactly this type of catalyst helps with the carbon dioxide incorporation into the polymer is very limited. However, a better understanding would allow us to improve catalyst design and enhance the performance even further. This project will therefore investigate how these catalysts incorporate carbon dioxide so well into polymers and how they can be optimized to function under lower carbon dioxide pressure and lower temperatures in order to lower their running costs.This project falls within the EPSRC "manufacturing the future" research theme.

塑料在我们的日常生活中随处可见。从食品包装、塑料袋和塑料瓶到床垫或房屋隔热材料中的泡沫，我们都使用它们。塑料是由聚合物制成的，聚合物是由许多积木(“单体”)组成的长链。为了形成聚合物，单体一个接一个地连接在一起，就像绳子上的珠子一样。根据单体的不同，所得聚合物的性质以及塑料的性质会有很大的不同。目前，几乎所有用于生产聚合物的单体都来自原油。这意味着我们依赖化石燃料来制造聚合物，而且与聚合物生产相关的碳排放相当大。为了应对气候危机，重要的是远离原油衍生的单体。要做到这一点，一种方法是用二氧化碳取代一半用于形成聚合物的单体。二氧化碳是一种有吸引力的单体，因为它无毒、可再生，而且价格低廉，因为它在许多工业过程中是作为废物产生的。使用二氧化碳作为单体可以通过两种方式减少聚合物的碳足迹。首先，在含二氧化碳的聚合物中，使用的单体中只有一半来自原油。这意味着，在单体生产过程中，需要生产的单体更少，排放到大气中的二氧化碳也更少。其次，作为单体使用的每个二氧化碳分子本来都会排放到大气中，但通过加入聚合物可以避免排放。然而，将二氧化碳加入聚合物中是非常困难的，因为它是非反应性的。为了克服这一点，可以使用一种被称为催化剂的化学物质。该催化剂加速了二氧化碳进入聚合物的反应，而不会在过程中被用完。催化剂还可以用来控制二氧化碳和其他单体连接的顺序。这一点很重要，因为不仅使用的单体类型，而且它们排列的顺序也将决定塑料的性质。自20世纪60年代末以来，已开发出用于将二氧化碳加入聚合物的催化剂。到目前为止开发的催化剂要么含有有毒成分，非常难以制造，要么需要高温或非常纯的二氧化碳。这使得它们价格昂贵，不便于大规模工业使用。最近发现了一种新型催化剂，含有无毒和富含稀土的金属，如钠、钾或镁。这是使用这些类型金属的催化剂的第一个例子。到目前为止，人们对这种催化剂如何帮助二氧化碳进入聚合物的了解非常有限。然而，更好的理解将使我们能够改进催化剂的设计，并进一步提高性能。因此，该项目将研究这些催化剂如何将二氧化碳很好地结合到聚合物中，以及如何对它们进行优化，使其在较低的二氧化碳压力和较低的温度下发挥作用，以降低其运行成本。该项目属于EPSRC“制造未来”研究主题。