文摘
Monoaldehyde compounds, benzaldehyde, 4-methylbenzaldehyde, 4-fluorobenzaldehyde, and 4-trifluoromethylbenzaldehyde, were utilized to react with melamine respectively to yield four hyper-cross-linked microporous polyaminal networks, PAN-P, PAN-MP, PAN-FP, and PAN-FMP, via a facile “one-step” polycondensation without adding any catalyst. It is found that relative to non-fluorinated polymers the fluorinated ones show the increased BET specific surface areas from 615 to 907 m2 g–1. Moreover, the incorporations of methyl and trifluoromethyl on the phenyl rings can effectively tailor the pore sizes from 0.9 to 0.6 nm. The polar C–F bond and nitrogen-rich polyaminal skeleton result in high CO2 adsorption enthalpies (38.7 kJ mol–1) and thereby raise the CO2 uptake up to 14.6 wt % (273 K, 1 bar) as well as large CO2/N2 and CO2/CH4 selectivities of 78.1 and 13.4 by the ideal adsorbed solution theory, respectively. The facile and scalable preparation method, low cost, and large CO2 adsorption and selectivities over N2 and CH4 endow the resultant microporous polyaminals with promising applications in CO2-capture from flue gas and natural gas.