Synthesis of polymeric ionic liquids material and application in CO2 adsorption

We synthesized one quaternary ammonium polymeric ionic liquids (PILs) P[VBTHEA] Cl and three imidazolium PILs of P[VEIm] Br, P[VEIm]BF4, P[VEIm]PF6 by free-radical polymerization in solution. These PILs were characterized by FT-IR, H-1-NMR, C-13-NMR, TGA, XRD and SEM. Their CO2 adsorption capacities were measured under different pressures and temperatures by constant-volume technique. It was observed that quaternary ammonium PILs of P[VBTHEA] Cl have higher adsorption capacity for CO2 than those imidazolium PILs, following P[VBTHEA] Cl > P[VEIm]PF6 > P[VEIm]BF4 > P[VEIm] Br, which may be ascribed to higher positive charge density on ammonium cation than that on imidazolium cation and thus stronger interaction with CO2, consistent with the results from dual-mode adsorption model that ammonium PILs have much higher CO2 bulk absorption than imidazolium PILs. CO2 adsorption capacity of P[VBTHEA] Cl is 9.02 mg/g under 295 K and 1 bar, which is comparable to that of some other PILs, and is much higher than that of the corresponding ILs monomer. These PILs have good adsorption selectivity for CO2 over N-2 and regeneration efficiency. (C) 2017 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.