| Introduction of ionic groups into a porous polymer skeleton will undoubtedly diversify the types of porous polymers and further broaden their applications,which could combine the advantages of both multifunctional materials as well as retaining the excellent properties of ionic liquids.In this paper,the 5,10,15,20-tetrakis(4-nitrophenyl)porphyrin(TNPP)compounds were used as monomers to conduct condensation reaction with two diamine monomers(5,5'-diamino-2,2'-bipyridine,NBPy)and(3,8-diamino-6-phenylphenanithridine,NPPN),and then four multi-functional CIFs materials were obtained with precursor following ionization by using bromoethane(C2H5Br)or dibromoethane(C2H4Br2)and then metallization by Zn or Co.The catalytic performance over cycloaddition reaction of carbon dioxide with epoxide compounds for obtaining cyclic carbonates was systematically studied.The resulting CIFs showed high efficiency in catalyzing the CO2 cycloaddition of propylene oxide(PO)to form propylene carbonate(PC).These specialized materials'specific surface area and the proportion of active sites in the materials can be regulated according to the change of the type of monomer/metal element,which also allowing one to explore the influence of these factors on the reaction performance of catalyzing the formation of cyclic carbonates from CO2 and epoxy compounds.All of the Zn containing CIF catalysts were able to catalyze the cycloaddition reaction with a PC yield of over 97%.Among the all synthesized catalysts,the catalyst Zn-CIF2-C2H4,which regenerated from TNPP/NBPy(CIF2)catalyst ionized with C2H4Br2 and metalized with Zn,exhibited the best catalytic activity.The high catalytic performance of Zn-CIF2-C2H4 was related to its large porosity(577 m2/g),high Br:metal ratio(1:3.89)as well as the excellent synergy between the Lewis acid Zn sites and the nucleophilic Br ion.We found that Zn-CIF2-C2H4 was stable that over 94%PC yield could be obtained even after 6 cycles.In addition,Zn-CIF2-C2H4 exhibited similar highly catalytic performance on the CO2 cycloaddition reaction of several others epoxides.Then,porous ionic COFs(3D-ICOF-X,X=Br or Cl)with three-dimensional structure was synthesized by TAPM and bipyridine salt through Zincke reaction via solvothermal method.Firstly,the experimental conditions were optimized:cationic covalent organic framework with high specific surface area was obtained by changing the synthesis temperature,solvent type and monomer ratio.Total synthesized materials were also test their every catalytic conversion value of CO2 to make cyclic carbonatefinally.One important found was given by that the varied specific surface area of the polymer ionic materials synthesized by Zincke reaction with different solvents,among which 1,3-dimethylene-2-imidazolinone(DMI)has the highest specific surface area.Relatively high temperature is conductive to high-temperature synthesis of materials,and the maximum specific surface area is obtained by increasing the synthesis temperature to the limit of 200?.It's not conducive to polymerization procedure for polymers with the too high or too low substrate ratio.The BET surface area value is touched to 122.34 m2/g,which is 2?3 times higher than before.In addition,3D-ICOF-X(X=Br or Cl)obtained have excellent swelling and solvent dispersion,which can promote the contact between active sites and reaction substrates and products,thus improving the influence of catalytic activity.The catalytic performance of ICOF catalyst was better than the activity of ionic monomer under the condition which may be attributed to the confined effect of the pores of microporous materials on anions to promote the contact between active sites and reaction substrates.Finally,the material can achieve the conversion rate of 99.3%under the pressure of 0.1MPa.Meanwhile,the catalyst has excellent stability and catalysis. |
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