A General and Mild Two‐Step Strategy Using Bioderived Diols and CO2 for Chemically Recyclable Polycarbonates and Closed‐Loop CO2 Fixation

Abstract Developing chemically recyclable polymers using CO 2 and sustainable co‐feedstocks is an important strategy for achieving carbon‐neutral production of new polymers and mitigating plastic pollution. Herein, a series of six‐membered cyclic carbonate monomers with different alkyl α ‐substituents were synthesized using CO 2 and bioderived 1,3‐alkanediol as raw materials at room temperature and atmospheric pressure. The organocatalytic ring‐opening polymerization was systematically studied using a range of common and readily available organocatalysts. Phosphazene base ( t ‐BuP 2 ) was identified as the most effective catalyst, offering excellent control over the entire polymerization. The regioselectivity of the synthesized polycarbonates, ranged from 0.74 to 0.99, with the highest value achieved when the side group was isopropyl (highest steric hindrance). Notably, the α ‐substituent in the monomers reduced the ring strains, allowing the resulting polycarbonates to be fully recycled to the monomers without decarboxylation. The recycling process effectively traps CO 2 in a closed loop between monomers and polymers, preventing its release into the atmosphere. The alkyl side groups enhanced the hydrophobicity of the polycarbonates, thereby reducing the likelihood of CO 2 release through hydrolysis during their lifecycle, achieving a robust CO 2 closed‐loop fixation. The utility of CO 2 ‐based aliphatic polycarbonates as adhesives and the ability of copolymerization with l ‐lactide were explored.