Monomer-Recyclable Polyesters From CO2 and 1,3-Butadiene

NOTE：This paper was first submitted for peer review at 31-Jan-2024, Manu-script ID: ja-2024-01537k. Recently, we found a very similar work published on ChemRxiv DOI: 10.26434/chemrxiv-2024-0p22l, therefore we decide to publish our work on ChemRxiv also. Synthesis of monomer-recyclable polyesters solely from CO2 and bulk olefins holds great potentials in significantly reducing CO2 emissions and addressing the issue of plastic pollutions. Due to the kinetic disadvantage of direct copolymerization of CO2 and bulk olefins compared to homopolymerization of bulk olefins, considerable research attention has been devoted to synthesis of polyester via the ring-opening polymerization (ROP) of a six-membered disubstituted lactone intermediate, 1,2-ethylidene-6-vinyl-tetrahydro-2H-pyran-2-one (𝜹-L), obtained from telomerization of CO2 and 1,3-butadiene. However, the conjugate olefin on the six-membered ring of 𝜹-L leads to serious Michael addition side reactions. Thus, selective ROP of 𝜹-L, which can precisely control the repeating unit for the production of polyesters potentially amenable to efficient monomer recycling, remains an unre-solved challenge. Herein, we report the first example of selective ROP of 𝜹-L using a combination of organobase and N,N′-Bis[3,5-bis(trifluoromethyl)phenyl]urea as the catalytic system. Systematic modifications of the substituent of the urea shows that the presence of electron-deficient 3,5-bis(trifluoromethyl)-phenyl groups is the key to the extraordinary selectivity of ring opening over Michael addition. Efficient monomer recovery of poly(𝜹-L) was also achieved under mild catalytic conditions. This work proves that it is possible to synthesize monomer-recyclable polyester by only using CO2 and bulk olefin as the feedstock, provid-ing a new strategy to potentially fix CO2 in polymeric materials at large scales.