Hierarchically Mesoporous o‐Hydroxyazobenzene Polymers: Synthesis and Their Applications in CO₂ Capture and Conversion

Abstract

The synthesis of hierarchically mesoporous polymers with multiple functionalities is challenging. Herein we reported a template-free strategy for synthesis of phenolic azo-polymers with hierarchical porous structures based on diazo-coupling reaction in aqueous solution under mild conditions. The resultant polymers have surface areas up to 593 m(2) g(-1) with the mesopore ratio of >80 %, and a good ability to complex with metal ions, such as Cu(2+) , Zn(2+) ,Ni(2+) , achieving a metal loading up to 26.24 wt %. Moreover, the polymers complexed with Zn showed excellent performance for catalyzing the reaction of CO2 with epoxide, affording a TOF of 2570 h(-1) in the presence of tetrabutyl ammonium bromide (7.2 mol %). The polymer complexed with Cu could catalyze the oxidation of alcohol with high efficiency.

Imidazolium‐Salt‐Functionalized Covalent Organic Frameworks for Highly Efficient Catalysis of CO2 Conversion

“…In these functionalized COFs, the turnover number (TON) of COF-HNU3 was as high as 495 000 (Table 1, entry 1), which is probably ar esulto fi ts high surfacea rea. [47,48] The as-prepared COF-HNU3 and COF-HNU4 have al arge amount of imidazolium cations and Br À anions,w hich can form hydrogen bonds with the epoxide, thus promoting the reaction of epoxides with CO 2 . Nevertheless,C OF-HNU2w ithoutc atalytic sites showedavery low catalytic activity under the same reaction conditions (entry 7).…”

Porous Organic Polymers for CO2 Storage and Conversion Reactions

“…Another important strategy for the synthesis of novel POPs is diazocoupling reaction. Liu and co‐workers have synthesized hierarchically mesoporous phenolic azopolymers (HAzo‐POPs) with multiple functionalities through diazo‐coupling reaction between the diazonium salts and phlorogluicinol in the aqueous medium . Hazo‐POPs showed BET surface areas of up to 593 m 2 g −1 and high affinity for the capture of selective metal ions (Cu 2+ , Zn 2+ , Ni 2+ ) from their respective aqueous solutions.…”

Metallosalen‐Based Ionic Porous Polymers as Bifunctional Catalysts for the Conversion of CO2 into Valuable Chemicals

“…[13a] The promising results implied that the catalyst DVB@ISAw ith micro-and mesoporous structure might make the diffusion of the substrate molecule favorably in spite of its different molecular size. [24] Unfortunately,c yclohexene oxide (CHO) as internal epoxide still remained with lower activity presumably ascribed to the high steric hindrance( Ta ble 2, entry 6). [25] All experimental resultso btainedf rom the POP catalyst DVB@ISAw ere similar to our previous works it had identical catalytic active moieties as the homogeneous catalystr eported previously.…”