Deconstruction of rubber via C–H amination and aza-Cope rearrangement

Limited strategies exist for chemical recycling of commodity diene polymers, like those found in tyres1–3. Here we apply C–H amination and backbone rearrangement of polymers to deconstruct these materials into precursors for epoxy resins. Specifically, we develop a sulfur diimide reagent4,5 that enables up to about 35% allylic amination of diene polymers and rubber. Then, we apply the cationic 2-aza-Cope rearrangement to deconstruct aminated diene polymers. In a model system, we see molecular weight reduction from 58,100 to approximately 400 g mol−1, and aminated post-consumer rubber is deconstructed over 6 hours into soluble amine-functionalized polymers, which can be utilized to prepare epoxy thermosets with similar stiffnesses to commercial bisphenol A-derived resins6. Altogether, this work demonstrates the power of C–H amination and backbone rearrangement to enable chemical recycling of post-consumer materials.