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年通过学生借调到公司进行管理。该项目属于EPSRC物理科学研究领域，特别关注化学科学和工程方面的重大挑战，即利用二氧化碳进行合成和改造化学工业。研究的重点是不对称大环的合成，它可以制备杂核配合物，而这在二氧化碳共聚方面只进行了少量的探索。在第一阶段，研究将涉及配体的制备、配位化学和异双核复合物形成的表征。异双核复合物的目标是利用Williams团队提出的机械假说（链穿梭）；这取决于两种金属在催化循环中的不同作用。为了验证这一假设，一系列使用族1、族2或族13的主族元素的配合物将与从Cr（III）、Fe（II/III）、Co（II/III）、Ni（II）和Zn（II）中选择的过渡金属元素结合。一些新的杂二透明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动、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。性能最好的催化剂将被选择用于进一步的开发和理解，因此重点是使用原位光谱确定聚合动力学。在确定速率定律之后，将重新评估和调整机械假设。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经济技术公司进行，在行业相关条件下进行。在第2/3年的借调期间，将能够在反应堆中测试领先的复合物，如果有足够的前景，将在客户开发现场进行测试。在测试二氧化碳/环氧化物共聚催化剂的同时，还将测试这些配合物作为使用酸酐和内酯的可切换聚合过程的催化剂。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估。这项工作的目的是评估可切换过程的催化剂，并将它们与目前的主要催化剂进行比较。进一步，开发以环氧丙烯为单体时挑战Al-salen配合物的催化剂。

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.