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

Towell, Sydney E; Ratushnyy, Maxim; Cooke, Lauren S; Lewis, Geoffrey M; Zhukhovitskiy, Aleksandr V · Nature · 2025

basic_science · Level V

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Abstract

Limited strategies exist for chemical recycling of commodity diene polymers, like those found in tyres<sup>1-3</sup>. 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 reagent<sup>4,5</sup> 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<sup>-1</sup>, 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 resins<sup>6</sup>. Altogether, this work demonstrates the power of C-H amination and backbone rearrangement to enable chemical recycling of post-consumer materials.