(573r) Excess Absorption of Type II Porous Liquids for CO2/H2 Separation

Porous liquids are believed to have potential in gas separations and can combine the benefits of the fluidity of solvents and the high capacity of porous solids. Type II porous liquids are rigid, discrete, porous host molecules dissolved in solvents that are too bulky to enter the pores. Porosity can be maintained in the liquid state, and the gas solubility in these porous liquids can be drastically increased over that of pure solvents. While Type II porous liquids have been primarily investigated for their synthesis and the existence of porosity, few isotherms have been reported to show the gas absorption ability of existing Type II porous liquids. Therefore, this work focuses on studying the CO₂ sorption behavior of Type II porous liquid and utilizes solution phase and adsorption thermodynamics to understand the role of porosity in Type II porous liquid. We measure the sorption isotherms of Type II porous liquid based on a specific porous organic cages CC13 and three solvents, namely 2’-hydroxyacetophenone (2HAP), 2-isopropylphenol (2IPP), and 2-chlorophenol (2CP) with different weight loadings. The excess absorption of all PLs is calculated to elaborate the absorption deviation from the additive combination of the cage and the solvent. A non-porous control molecule and CC13 with different crystalline structures are used to probe the mechanism of the positive deviation from volume additivity. Another POC, CC19, is first used to form Type II porous liquids and excess absorption can also be observed in the new PLs. The results of this study provide valuable insights into the potential gas separation applications of Type II porous liquids.