Tetraphenyladamantane-based microporous polyaminals for efficient adsorption of CO2, H2 and organic vapors

Herein, a new tetraphenyladamantane-cored triazine-based multiamine (TPADT) was designed and synthesized. Its bulky molecular volume, strong rigidity, and high amine functionality enable it easy to prop up the polymer backbone and form a high hypercrosslinking degree to obtain high microporosity. A series of highly microporous tetraphenyladamantane-based polyaminals (Ad-MALPs) were prepared through the catalyst-free copolymerization of TPADT and commercial aromatic aldehydes. By changing the strut length and functionality of aldehyde monomers, the resulting polymers exhibit tailored BET surface area (1541-1779 m(2)/g) and narrow ultramicropore size distribution (0.52-0.93 nm). Ad-MALP-2 with the largest microporosity possesses the highest CO2 uptake (21.1 wt %, 273 K/1.0 bar) and CO2/N-2 adsorption selectivity (35.2). Interestingly, Ad-MALP-3 shows the highest H-2 uptake (2.26 wt%, 77 K/1.0 bar) due to larger total pore volume. In addition, highly microporous AdMALPs simultaneously contain aromatic and cycloaliphatic components, and thus show exceptionally large aromatic and cycloaliphatic organic vapor adsorption capacity under low pressure. At P/P-0 = 0.1, the benzene and cyclohexane vapor uptakes of Ad-MALPs are up to 44.8 wt% and 39.0 wt %, far exceeding that of most previously reported porous organic polymers. Considering that Ad-MALPs have outstanding gas adsorption performance, simple preparation, good stability, and cycle ability, they are expected to be promising adsorbent materials for CO2 adsorption/separation, H2 storage and low-concentration volatile organic vapors capture.

Automated summary

The newly synthesized TPADT triazine-based multiamine was used to prepare highly microporous Ad-MALPs through catalysis-free copolymerization, resulting in customized BET surface area and narrow ultramicropore size distribution.