Catalytic Upgrading of Polymer Waste into Value-Added Products

塑料在现代社会的发展中发挥了重要作用，但与该行业相关的日益增长的环境问题使人们对可再生替代品产生了兴趣。事实上，随着工业从线性经济向循环经济转变，很明显有必要制定替代废物管理战略，以补充生物基和可生物降解塑料的引入。因此，该项目旨在：-研究商业生物基塑料（如PLA）的催化升级（通过化学回收）为增值产品，如乳酸酯或丙烯酸，这些产品被认为是传统石化基溶剂/化学品的潜在绿色替代品。该过程的关键方面包括：开发新颖的、工业上可行的催化剂（即使用廉价/丰富的金属和可扩展的配体系统）。-在温和条件下的高选择性和收率，金属介导的降解例子仍然有限。事实上，目前的回收方法依赖于苛刻的反应条件，是资源/能源密集型的，并且在机械回收的情况下导致最终的材料“降级循环”。化学回收有可能解决这些问题。-在新型旋转圆盘反应器上展示工艺可扩展性，采用跨学科的方法，在化学和工程的边界上工作。-将已建立的方法扩展到其他商业上相关的聚酯，包括PET和PEF，以及其他聚合物类别：聚碳酸酯，聚酰胺等-将开发的催化剂固定在支架上，以克服与催化剂回收率相关的行业问题，这是均相催化剂的限制特征。这也将有助于提高现有的回收技术。此外，还将研究所制备的所有新型催化剂在溶液和工业上首选的PLA生产和聚碳酸酯形成（CO2/环氧化物或酸酐/环氧化物）熔融条件下对rac-LA ROP的活性。感兴趣的聚合物将使用标准的热/机械表征技术进行表征。项目策略:1。可扩展配体的制备，如希夫碱。与(I)族、（II）族、Zn.3族等多种富土金属络合。催化试验（批量和流动）。评估催化数据，确定结构-活性关系，通过实验和计算模型了解催化升级过程。开发催化反应器，扩大降解规模，从废料中制备高附加值产品。引用:1。J. Payne， P. McKeown和M. D. Jones, Polym。Degrad。刺。浙江农业学报，2019,165,170-181。

Plastics have played an instrument role in the development of modern day society, but growing environmental concerns associated with the industry has created an appetite for renewable alternatives. Indeed, it is clear the development of alternative waste management strategies is necessary to compliment the introduction of bio-based and biodegradable plastics as the industry shifts from a linear to circular economy. Thus, this project aims to:- Investigate catalytic upgrading (via chemical recycling) of commercially bio-based plastics (e.g. PLA) into value-added products, such as lactate esters or acrylic acid, which have been cited as potential green substitutes for traditional petrochemical based solvents/chemicals. Key aspects to this process include:Development of novel, industrially viable catalysts (i.e. using cheap/abundant metals and scalable ligands systems).- High selectivity and yield under mild conditions, with metal-mediated degradation examples remaining limited. Indeed, current recycling methods rely on harsh reaction conditions, are resource/energy intensive and lead to eventual material 'downcycling' in the case of mechanical recycling 1 Chemical recycling has the potential to address these concerns. - Demonstrate process scalability on a novel spinning disc reactor, adopting an interdisciplinary approach to research by working at the boundary between chemistry and engineering.- Extend established methodologies to other commercially relevant polyesters, including PET and PEF, but also other polymer classes: polycarbonates, polyamides etc.- Immobilize developed catalysts on a support to overcome industry concerns associated with catalyst recovery, a limiting feature of homogeneous catalysts. This will also assist in upscaling the established recycling technology. Additionally, all novel catalysts prepared will also be investigated for their activity in the ROP of rac-LA in both solution and under industrially preferred melt conditions for PLA production and for polycarbonate formation (CO2/epoxide or anhydride/epoxide). Polymer of interest will be characterised using standard thermal/mechanical characterisation techniques.Project strategy:1. Preparation of scalable ligands, for example Schiff-Base.2. Complexation to broad range of earth abundant metals e.g. Group (I), Group (II) and Zn.3. Catalytic testing (batch and in flow).4. Evaluate catalytic data to determine structural-activity relationships to understand catalytic upgrading processes through experimental and computational modelling.5. Develop catalytic reactor to scale up the degradation and to prepare value-added products from waste materials. References:1. J. Payne, P. McKeown and M. D. Jones, Polym. Degrad. Stab., 2019, 165, 170-181.