Conversion of waste poly(vinyl chloride) to branched polyethylene mediated by silylium ions

Full dechlorination of poly(vinyl chloride) (PVC) in a controlled manner to yield useful polymeric and chlorinated products is of great interest for the processing of PVC waste. Forming polyethylene (PE) without corrosive by-products would allow for a pre-treatment of PE wastes that are often contam...

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Published in:Chemical science (Cambridge) Vol. 15; no. 23; pp. 8766 - 8774
Main Authors: Wood, Zachary A, Castro, Eunice C, Nguyen, Angelyn N, Fieser, Megan E
Format: Journal Article
Language:English
Published: England Royal Society of Chemistry 12-06-2024
The Royal Society of Chemistry
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Summary:Full dechlorination of poly(vinyl chloride) (PVC) in a controlled manner to yield useful polymeric and chlorinated products is of great interest for the processing of PVC waste. Forming polyethylene (PE) without corrosive by-products would allow for a pre-treatment of PE wastes that are often contaminated with PVC. Herein, full dechlorination of PVC has been achieved via generation of silylium ions in situ , to furnish PE products. Complete dechlorination of PVC can be achieved in 2 hours, yielding organic polymer that has similar spectroscopic and thermal signatures of branched PE, with no observable chlorine. The degree of branching can be tuned between 31 and 57 branches per 1000 carbons, with melting temperatures ranging from 51 to 93 °C. This method is applicable to not only pure PVC, but also commercial PVC products. Depending on if the PVC products are separated from plasticizers, different melting points of the resulting PE are observed. PVC dechlorination in the presence of PE waste is also shown. This is the first report of being able to cleanly convert PVC waste to PE in high yields and tune the thermal properties of the PE product, highlighting the remarkable control that silylium ion mediated transformations enables compared to past chemical methods. Lewis acidic silylium ions are used to completely remove Cl from poly(vinyl chloride) (PVC) in clean and commercial products through hydrodechlorination. Reaction conditions were found to impact the branching in the resulting polyethylene (PE).
Bibliography:https://doi.org/10.1039/d4sc00130c
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AC02-07CH11358; DBI-0821671; CHE-0840366; S10 RR25432; 60NANB22D134
USDOE
National Science Foundation (NSF)
USDOE Office of Science (SC), Basic Energy Sciences (BES)
National Institute of Standards and Technology (NIST)
National Institutes of Health (NIH)
ISSN:2041-6520
2041-6539
DOI:10.1039/d4sc00130c