Directed Synthesis And Ethylene Purification Performance Of Nia-d/pek Topologically Oriented MOF Materials

Ethylene production is the important sign of a country's industrial level.However,the conventional separation method and process are highly energy-intensive.In contrast,as emerging porous solid materials,metal-organic frameworks(MOFs)have proved their potential applications toward the green and efficient purification of ethylene.In this thesis,two series of high-connected nia-d/pek topological MOFs have been judiciously designed and successfully constructed considering their controllable synthesis and ease of fine-tuning targeting the high purification performance of ethylene relevant to separations of C2H6/C2H4 and C3H6/C2H4,respectively.(1)In the first part,three iron-based quaternary MOFs(i.e.,compounds 1-3)based on(3,9)-c nia-d topology have been purposely designed and successfully synthesized,which were detailedly characterized by single crystal X-ray diffraction(SCXRD),powder X-ray diffraction(PXRD),thermal gravimetric analysis(TGA),and fourier transform infrared(FTIR)spectroscopy as well as gas sorption and separation investigations.The structural analysis reveals that compounds 1-3 are isoreticular and composed of respective trigonal bipyramid and anti-triangular prism cages accociated with different pore diameters and aperture sizes due to the newly introduced trinitrogen metalloligand of[Cu3(trz)3]and the employment of differing functional dicarboxylate linkers,resulting in distinct gas sorption and separation.Among them,compound 1 has no C2H4/C2H6 separation performance;compound 2 has the characteristic of selective adsorption of C2H6,which can realize the one-step purification of C2H4 in C2H6/C2H4 mixed gas and compound 3 exhibits the ordinary selective adsorption of C2H4 over C2H6.In addition,the single crystalline Fe-MIL-101-1,4-NDC phase,i.e.,compound 4,was discovered during the preparation of compound 3 for the first time,which displays selective C2H6 adsorption over C2H4.(2)Both isostructural amide-functionalized hexanuclear rare earth(RE=Y or Yb)compounds 5 and 6 based on(3,8,12)-c pek topology,have been judiciously and successfully constructed.Both materials were characterized by PXRD,TGA,FTIR and gas sorption and separation measurements.The structural analysis shows that compounds 5 and 6 encompass hexagonal bipyramid and 1D channels interconnected in three directions.Due to the presence of the polar amide group in the structures,both compounds exhibit selective C3H6 adsorption over C2H4,indicating their potential and effective separation toward C3H6/C2H4 mixture.