Hydroxide Based Integrated CO₂ Capture from Air and Conversion to Methanol

The first example of an alkali hydroxide-based system for CO₂ capture and conversion to methanol has been established. Bicarbonate and formate salts were hydrogenated to methanol with high yields in a solution of ethylene glycol. In an integrated one-pot system, CO₂ was efficiently captured by an ethylene glycol solution of the base and subsequently hydrogenated to CH₃OH at relatively mild temperatures (100-140 °C) using Ru-PNP catalysts. The produced methanol can be easily separated by distillation. Hydroxide base regeneration at low temperatures was observed for the first time. Finally, CO₂ capture from ambient air and hydrogenation to CH₃OH was demonstrated. We postulate that the high capture efficiency and stability of hydroxide bases make them superior to existing amine-based routes for direct air capture and conversion to methanol in a scalable process.