Preparation And Gas Adsorption Performance Of Novel Microporous Organic Polymers

Microporous organic polymers(MOPs)have demonstrated great potential in gas adsorption,separation,storage,heterogeneous catalysis and energy devices.However,scale-up and environmentally-friendly preparation of MOPs with high performance still remains great challenges.Within this context,two microporous organic materials,fluorine-containing CTFs and asphalt-based HCPs,were successfully prepared and their gas uptake properties were systematically investigated in the present thesis.The two aspects are described respectively as follow:(1)The fluorine-containing CTFs with large surface areas were prepared with tetrafluoroisophthalonitrile as monomer under typical ionothermal condition.For purpose of comparison,the CTFs without fluorine were also obtained via identical method using isophthalonitrile as building block.It should be noted that CFn will be generated due to the defluorination process during the high-temperature cyclotrimerization.The released gases further etched the frameworks,resulting in abundant microporosities.Detailed characterizations demonstrated the high thermochemical stability and large porosities of the fluorine-containing CTFs which had a maximum BET surface area of 1388 m2/g and a high ratio of microporosity up to 0.87;besides,the residual fluorine groups and nitrogen atoms along with the dominating microporosity endowed the materials with excellent CO2 uptake capacity up to 23.1 wt%(273 K,1.0 bar),which outperformed most of the CTFs materials.Thus,the fluorine-containing CTFs exhibit great potential for CO2 capture and storage.(2)A series of asphalt-based microporous organic polymers were prepared with asphalt and formaldehyde dimethyl acetal as building block and crosslinker respectively via one-step Friedel-Crafts reaction catalyzed by three kinds of heteropoly acids(HPAs)including phosphotungstic acid(HPW),tungstosilicic acid(HSiW)and phosphomolybdic acid(HPMo).The as prepared products demonstrated identical structures and morphologies compared with those obtained through traditional strategies.Further gas adsorption investigation indicated these materials displayed large surface areas,good CO2 and H2 uptake performance.Moreover,the employed catalysts could be recycled with yields up to 95%and reused at least 9 times with excellent catalytic performance retention.Thanks to the novel HPA catalyst/FDA crosslinker system,not only the corrosive gases released during the conventional methods are avoided completely,but also the recovery and reutilization of catalysts can be achieved.Thus,this newly developed heteropoly acid-promoted approach with great environmentally friendly superiority for the preparation of asphalt-based MOPs may open up a way to the practical preparation and application of MOPs.