Integrated carbon capture and utilization to methanol with epoxide-functionalized polyamines under homogeneous catalytic conditions

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Herein, a novel amine based integrated process is presented for CO2 capture and utilization (CCU) to synthesize methanol. Reaction of pentaethylenehexamine (PEHA) with selected epoxides led to a library of functionalized polyamines. In aqueous medium, the modified amines were efficient in capturing CO2 under ambient conditions. Subsequently, the CO2 loaded solutions were directly subjected to catalytic hydrogenation to CH3OH in presence of molecular H2 and Ru-PNP based molecular catalysts. While the epoxide-modified amines exhibited CO2 capture efficiencies comparable to those of unmodified PEHA, they displayed a notable enhancement in the hydrogenation step resulting in higher methanol yields of up to 93%. Furthermore, the integrated process was demonstrated in a water and 2-methyl-THF based biphasic solvent system. We believe that the improved amine-based system for CO2 capture and hydrogenation to methanol is key in advancing low temperature and renewable methanol synthesis processes.