Understanding the competition between hydrodechlorination and Friedel–Crafts alkylation in PVC dechlorination with silylium ions†

IF 3.9 2区化学 Q2 POLYMER SCIENCE

Polymer Chemistry Pub Date : 2025-05-06 DOI:10.1039/d5py00242g

Nicholas J. Roubineau , Eunice C. Castro , Kaustubh Rane , Zachary A. Wood , Angelyn N. Nguyen , Nancy G. Bush , Ayon Das , Shaama Mallikarjun Sharada , Megan E. Fieser

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Abstract

The combination of hydrodechlorination and Friedel–Crafts alkylation using silylium ions is a rapid route to fully dechlorinate poly(vinyl chloride) (PVC), while producing organic and chlorine-based products that have value for a second life. This silylium reaction has been optimized for full dechlorination under ambient conditions for a range of temperatures. Additionally, tetramethyldisiloxane is introduced as a cheaper and more moisture-stable silane, which shows similar activity as triethylsilane. While high selectivity for Friedel–Crafts alkylation has been achieved for molecular silylium chemistry, analogous attempts with PVC as a substrate have revealed a maximum arene incorporation below 30%. However, reaction conditions and choice of aromatic solvent show dramatic changes in thermal properties of the polyethylene-co-poly(vinyl arene) polymer product. These differences in thermal properties align with a variable side reaction of secondary Friedel–Crafts alkylation, either intramolecularly to form polyindene repeating units or intermolecularly to form crosslinks.

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了解氢化脱氯与Friedel-Crafts烷基化在PVC硅离子脱氯中的竞争

氢化脱氯和使用硅离子的Friedel-Crafts烷基化相结合是一种快速的方法，可以使聚氯乙烯（PVC）完全脱氯，同时生产具有二次使用价值的有机和氯基产品。该反应在一定温度范围内的环境条件下完全脱氯。此外，介绍了四甲基二硅氧烷作为一种更便宜和更湿稳定的硅烷，其活性与三乙基硅烷相似。虽然分子硅化学的Friedel-Crafts烷基化已经实现了高选择性，但用PVC作为底物的类似尝试表明，芳烃的最大掺入量低于30%。然而，反应条件和芳烃溶剂的选择对聚乙烯-共聚乙烯烃聚合物产物的热性能有较大的影响。这些热性能的差异与二级Friedel-Crafts烷基化的可变副反应相一致，要么在分子内形成多独立重复单元，要么在分子间形成交联。

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来源期刊

Polymer Chemistry POLYMER SCIENCE-

CiteScore

8.60

自引率

8.70%

发文量

535

审稿时长

1.7 months

期刊介绍： Polymer Chemistry welcomes submissions in all areas of polymer science that have a strong focus on macromolecular chemistry. Manuscripts may cover a broad range of fields, yet no direct application focus is required.