The introduction of a base component to porous organic salts and their CO2 storage capability

Abstract

Porous organic salts (POSs) are constructed by charge-assisted hydrogen bonding between amino and sulfonic groups, and can be used to design a variety of porous structures based on molecular design. In particular, triphenylmethylamine (TPMA) and aromatic sulfonic acids form robust POSs with a rigid diamond structure (d-POSs). In this study, by replacing one of the three phenyl rings of TPMA with a pyrimidine ring, we succeeded in constructing a d-POS with high porosity (43.8%) and with a base component (pyrimidine) on the void surface. In addition, the weak basicity of the pyrimidine did not interfere with the formation of d-POSs. This d-POS adsorbed CO₂ over the primary air components (N₂ and O₂) and also exhibited CO₂ storage capability: It retained CO₂ at a relatively low pressure of P_e/P₀ = 0.05, and readily desorbed CO₂ below P_e/P₀ = 0.05.