Hydroxylamine-anchored
covalent aromatic polymer (CAP-DAP) was
synthesized from <i>p</i>-terphenyl and 1,3,5-benzene tricarbonyl
chloride, followed by subsequent functionalization with 1,3-diamino-2-propanol
for CO<sub>2</sub> capture and metal-free catalysis in CO<sub>2</sub>–epoxide cycloaddition reactions. The novel CAP-DAP material
was characterized using various analytical techniques. It showed very
good CO<sub>2</sub> adsorption capacity of 153 mg/g along with a high
(CO<sub>2</sub>/N<sub>2</sub>) selectivity of 86 at 273 K/1 bar, in
contrast to bare CAP, which exhibited moderate CO<sub>2</sub> adsorption
of 136 mg/g with a CO<sub>2</sub>/N<sub>2</sub> selectivity of 47.
CAP-DAP also displayed high catalytic activity for CO<sub>2</sub>–epoxide
cycloaddition reactions under mild and solvent-free conditions. The
synergistic effect between metal-free CAP-DAP and tetrabutylammonium
bromide (<i>n</i>-Bu<sub>4</sub>NBr) enabled a high epoxide
conversion of 98% coupled with an excellent product selectivity of
99% at 60 °C, 1 bar CO<sub>2</sub>, and a reaction time of 12
h. Faster reaction kinetics with reaction times <6 h was possible
at 80 °C. The catalyst also showed excellent reusability and
no leaching of active species was observed from the spent catalyst.
Based on experimental results, a plausible reaction mechanism for
CO<sub>2</sub>–epoxide cycloaddition reaction over CAP-DAP
catalyst has been proposed
