(519h) Development of Aminopolymer-Based Sorbents for CO2 Capture with Improved Capacity and Oxidative Stabilit

Sustainable and regenerable carbon capture materials, such as poly(ethyleneimine) (PEI) and other aminopolymers supported in mesoporous solids, have been widely studied as they can effectively capture CO₂ from both flue-gas (10% CO₂) and from ambient air, via direct-air-capture (400 ppm CO₂). Primary and secondary amines act as the adsorptive/reactive centers for the capture of CO₂; however, the secondary amines are susceptible to oxidative degradation at elevated temperatures, which results in loss of CO₂ capture capacity. This oxidative stability is especially vital for air-capture adsorbents due to the presence of high concentrations of oxygen in the dilute CO₂ feed stream.

Preliminary work on small oligomers and dendrimers with ethyl versus propyl backbones indicated amines separated by propyl linkers have increased CO₂ capture capacity and are more stable under oxidation conditions [1]. We extend this work to synthesize a propyl analog of commercially available branched PEI, i.e. poly(propyleneimine) (PPI) from cationic ring opening polymerization of azetidine. Amine oxide sorbents are prepared through impregnation of mesoporous silica (SBA-15) with the polymer and the CO₂ capture capacity and oxidative stability are investigated.

[1] S.H. Pang, L.Lee, M.A. Sakwa-Novak, R.P. Lively, C.W. Jones, J. Am. Chem. Soc. 139 (2017) 3627−3630