For the upcycling of waste polyethylene terephthalate (PET), encompassing both colored and fabric PET materials, we investigated the Ir(triNHC)-catalyzed dehydrogenative coupling of PET and methanol, leading to the production of sodium lactate with good yields. We proposed a sustainable method for isolating lactic acid from the catalytic reaction mixture of sodium lactate and regenerating the base using bipolar membrane electrodialysis (BMED). This isolation method demonstrated high effectiveness, achieving isolation of lactic acid while maintaining economic feasibility at $ 0.10 per kg of lactic acid, and enabling sustainable NaOH regeneration with complete resource circulation. We assessed the recyclability of the catalyst and elucidated the mechanism involving base-mediated depolymerization and catalyst-promoted dehydrogenation, highlighting the importance of triNHC ligands in enhancing catalytic activity.
This study was supported by the Carbon to X Program (No. 2020M3H7A1098283) and National Research Foundation Program (No. 2022R1A2C1004387) funded by the Ministry of Science and ICT and LAMP program (No. RS\\u20102023\\u201000285390) funded by the Ministry of Education, Republic of Korea. YKH is kindly grateful to the carbon dioxide conversion of platform chemicals using under\\u2010utilized biomass resources (2022M3J5A1059161) program funded by the Ministry of Science and ICT.
