Polymerisation Catalysts enabling Carbon Dioxide Utilization

该项目将专注于发现、开发和表征能够实现二氧化碳共聚过程的新催化剂，以减少塑料生产对化石燃料的依赖。它将涉及与行业共同赞助商Econic Technologies的密切合作，通过定期会议和在研究的第2/3年借调到公司的学生进行管理。该项目福尔斯属于EPSRC物理科学研究领域，特别关注化学科学和工程的重大挑战，即在合成和改造化学工业中利用二氧化碳。研究重点是合成不对称大环化合物，从而能够制备异双核配合物，在这里仅对二氧化碳共聚进行了少量探索。在第一阶段，研究将解决配体制备，配位化学和异双核配合物形成的表征。异双核配合物的目标是利用威廉姆斯团队提出的一种机制假说（链穿梭）;它依赖于两种金属在催化循环中的不同作用。为了检验该假设，将使用来自第1、2或13族的主族元素的一系列络合物与选自Cr（III）、Fe（II/III）、Co（II/III）、Ni（II）和Zn（II）的过渡金属元素组合。一些新的heterodinclear配合物具有顺磁性金属中心，因此表征实验将包括标准光谱测量以及循环伏安法，SQUID，EPR和XPS等专业技术。新的催化剂将在环氧化物/CO2的交替共聚中进行测试。成功的衡量标准包括活性、选择性和控制，并将使用威廉姆斯集团开发的协议和设备进行评估。将选择性能最好的催化剂进行进一步的开发和理解，因此重点是使用原位光谱法确定聚合动力学。在确定速率定律之后，将重新评估和微调机械假说。我们还将进行实验，以确定催化中间体和非循环过程（副反应/降解产物）。催化剂的测试也将在Econic Technologies在行业相关条件下进行。在第2/3年的一段借调期内，将能够在反应堆中测试领先的复合体，如果有足够的希望，将在客户开发现场进行测试。在测试CO2/环氧化物共聚催化剂的同时，还将测试复合物作为使用酸酐和内酯的可切换聚合工艺的催化剂。聚合活性和选择性将使用威廉姆斯实验室开发的方法进行评价。这项工作的目标是评估可切换过程的催化剂，并将其与当前领先的催化剂进行比较。此外，开发当使用环氧丙烷作为单体时挑战Al-salen络合物的催化剂。

The project will focus on the discovery, development and characterisation of new catalysts enabling carbon dioxide copolymerisation processes, in order to reduce the reliance on fossil fuel for plastic production. It will involve close collaboration with the industry co-sponsor, Econic Technologies, managed through regular meetings and by a student secondment to the company in year 2/3 of the research. The project falls within the EPSRC Physical science research area, specifically looking at the Chemical sciences and engineering grand challenge of utilising carbon dioxide in synthesis and transforming the chemical industry.The research focuses on the synthesis of asymmetric macrocycles which enable the preparation of heterodinuclear complexes, which have here to been only marginally explored for carbon dioxide copolymerisation. In the first stages, research will address ligand preparation, coordination chemistry and characterisation of heterodinuclear complex formation. Heterodinuclear complexes are targeted to take advantage of a mechanistic hypothesis proposed by the Williams team (chain shuttling); it relies on different roles for the two metals in the catalytic cycle. To test the hypothesis a series of complexes using a main group element from Group 1, 2 or 13 will be combined with a transition metal element selected from Cr(III), Fe(II/III), Co(II/III) Ni(II) and Zn(II). Some of the new heterodinclear complexes feature paramagnetic metal centres and thus characterization experiments will include standard spectroscopic measures as well as specialist techniques like cyclic voltammetry, SQUID, epr and XPS. The new catalysts will be tested in the alternating copolymerisation of epoxides/CO2. The measures of success include activity, selectivity and control and will be assessed using protocols and equipment developed in the Williams group. The best performing catalysts will be selected for further development and understanding, thus focusses on determining the polymerisation kinetics using in situ spectroscopies. After determination of the rate laws, the mechanistic hypothesis will be re-evaluated and fine-tuned. We will also conduct experiments to identify catalytic intermediates and off-cycle processes (side-reactions/degradation products). The testing of the catalyst will also occur at Econic Technologies, under industry relevant conditions. A period of secondment in year 2/3 will enable testing of leading complexes in reactors and, if sufficiently promising, at the customer development site. In parallel with testing the catalyst for CO2/epoxide copolymerisation, the complexes will also be tested as catalysts for switchable polymerisation processes using anhydrides and lactones. The polymerisation activity and selectivity will be evaluated using methods developed by the Williams laboratory. The goal of this work are to evaluate the catalysts for switchable processes and to compare them to current leading catalyst. Further, to develop catalysts which challenge the Al-salen complexes when using propene oxide as a monomer.