A new strategy for CO₂ utilization with waste plastics: Conversion of hydrogen carbonate into formate using polyvinyl chloride in water

This work reports the first observation of the reduction of hydrogen carbonate to formate with polyvinyl chloride (PVC) as a hydrogen source in high-temperature water. Results show that NaHCO₃ is successfully converted into formate with a 16% yield and nearly 100% selectivity based on hydrogen carbonate, simultaneously achieving the complete dechlorination of PVC at 300 °C. The mechanistic study suggests that CH-OH group formation from the substitution reaction of chlorine in PVC by OH^- is an important starting step, and then the CH-OH group and HCO₃^- react to form formate via a redox reaction. Moreover, the selection of water as the reaction medium played a key role in the reduction of HCO₃^- to formate using PVC. The present study provides a new and green method for not only hydrogen carbonate/CO₂ conversion but also PVC waste dechlorination in a single step.