Lemmens Robin, Vercammen Jannick, Van Belleghem Lander, De Vos Dirk
Centre for Membrane Separations, Adsorption, Catalysis and Spectroscopy (cMACS), KU Leuven, Celestijnenlaan 200F, post box 2454, 3001, Leuven, Belgium.
Nat Commun. 2024 Oct 24;15(1):9188. doi: 10.1038/s41467-024-53506-9.
Polyolefins are the most widely produced type of plastics owing to their low production cost and favorable properties. Their polymer backbone consists solely of inert C-C bonds, making them resistant and durable materials. Although this is an extremely useful attribute during their use phase, it complicates chemical recycling. In this work, different types of polyethylenes (PEs) are converted into ketone-functionalized PEs with up to 3.4% functionalized carbon atoms, in mild conditions (≤100 °C), using a titanosilicate catalyst and tert-butyl hydroperoxide as the oxidant. Subsequently, the introduced ketones are exploited as sites for heteroatom insertion. Through Baeyer-Villiger oxidation, in-chain esters are produced with yields up to 73%. Alternatively, the ketones can be converted into the corresponding oxime, which can undergo a Beckmann rearrangement to obtain in-chain amides, with yields up to 75%. These transformations allow access to polymers that are amenable to solvolysis, thereby enhancing their potential for chemical recycling.
聚烯烃是产量最高的一类塑料，这得益于其低廉的生产成本和优良的性能。它们的聚合物主链仅由惰性的碳 - 碳键组成，使其成为具有抗性和耐用性的材料。尽管这在其使用阶段是一个极其有用的特性，但它使化学回收变得复杂。在这项工作中，使用钛硅酸盐催化剂和叔丁基过氧化氢作为氧化剂，在温和条件下（≤100°C），将不同类型的聚乙烯（PE）转化为酮官能化的PE，官能化碳原子含量高达3.4%。随后，引入的酮被用作杂原子插入的位点。通过拜耳 - 维利格氧化反应，可生产出产率高达73%的链内酯。或者，酮可以转化为相应的肟，肟可进行贝克曼重排以获得产率高达75%的链内酰胺。这些转化使得能够获得适合溶剂分解的聚合物，从而提高其化学回收的潜力。
