Oxidative Recycling of Polyethylene: Mechanistic Insights into O2/NO-Mediated Oxidative C–C Cleavage of Linear Alkanes

Oxidative chemical recycling of polyethylene (PE) provides a strategy to convert the waste polymer into oxygenated chemical building blocks, and conditions that use O₂/NO show particular promise. Here, we probe the mechanism of O₂/NO-mediated conversion of linear alkane into carboxylic acids, using n-decane and high-density polyethylene (HDPE) substrates. Reactions with decane enable identification and quantification of reactive intermediates, including nitrites, nitrates, alcohols, and ketones. Under the reaction conditions, these species convert into common ketone intermediates that evolve into α-diketones and other α-functionalized ketones, which undergo further conversion into carboxylic acids. Infrared (IR) spectroscopy confirms that HDPE oxidation proceeds through similar key intermediates. These findings provide an important foundation for further development of oxidative chemical recycling of PE.