We utilized Potential Energy Scans with the AMS Software with the CHON-2019 Reax ForceField to estimate transition barriers from the linear carbonates to its corresponding cyclic carbonate and methanol via two paths based on hydrogen atom position (Fig. ). RDkit was used to standardize the starting point of each linear carbonate system by recreating the geometries of different functional groups attached to the C2-carbon (Fig. ) in the carbonate monomer. This code only requires the SMILES representation of the functional group which will be attached. The structures of all the corresponding cyclic carbonate monomers investigated are provided in Fig. ) and Supplementary Fig. (2a-ar).