| The alkane account for important position in the industrial production. The acetylene is an important starting material in the petrochemical and electronic industry for various industrial and consumer products and a promising alternative energy source for future acetylene fuel cell vehicles. The ethane is one of the important raw materials for cracking ethylene. The ethylene is widely used to produce polymers. And methane is a new kind of clean energy. So the mentioned gas storage and selective separation in industry has very important significance.As a new member of the novel inorganic-organic hybrid materials, metal-organic frameworks (MOFs) has the following advantages:variety, functional, large porosity and specific surface area, small crystal density, tuned the pore. Hence MOFs has drawn great attentions due to their broad applications in gas storage and selective separation, catalysis, luminescence and sensing, etc. To solve the problems in improving the gas storage capacity and separation selectivity of present MOFs materials, we propose the strategies of the expansion and bending of the organic ligands, modified functional groups and control aperture sizes, and design and prepare the four kinds of new type of copper-organic frameworks materials, to explore and research the different modification strategies on the role of the gas storage and selective separation, which provides experimental and theoretical basis for further improving energy gas storage capacity and separation selectivity.Introducing anthracene nucleus into organic linker BPTC (3,3’-5,5’-biphenyl-tetracarboxylate), a new three-dimensional microporous metal-organic frameworks Cu2(ADDI) (ZJU-26; H4ADDI= 5,5’-(anthracene-2,6.diyl)-diisophthalic acid) was solvothermally synthesized. The activated ZJU-26a exhibits excellent properties of storage of CH4, CO2 and C2 alkane and selective separation of C2H2/CH4 and C2H2/CO2 at room temperature. ZJU-26a can take up C2H2 (84 cm3/g), C2H4(60 cm3/g) and C2H6 (48 cm3/g) at room temperature, which are consistent with microporous MOFs materials. The working capacity of methane from 35 and 65 to 5 bar at 300 K are 94 cm3(STP)/cm3 and 132 cm3(STP)/cm3, respectively. At 300 K and 28 bar, the storage capacity of CO2 is 653.4 mg/g, which achieves 40% of quality capacity. At 298 K, ZJU-26a has the C2H2/CH4 and C2H2/CO2 gas separation with separation selectivity of 45.9 and 12.5 at room temperature, which indicated that ZJU-26a can highly selectively separate for C2H2/CH4 and C2H2/CO2. The outstanding performance of gas storage and selective separation of ZJU-26a attributes to microporous effect and π-π effect, which enhance the interaction of MOFs with gas molecules.We report a porous MOFs material Cu6(DDCBA)3 (ZJU-72; H5DDCBA= 3,5.di (3’,5’-dicarboxylpheny)-benozoic acid) with exposed-COOH. When the material is heated in vacuum, the pores possess multifunctional modified site with open metal site and exposed carboxylic acid groups. At 273 K, the henry law selectivities for C2H2/CH4, C2H4/CH4, QH6/CH4 and C2H2/CO2 are 91,44,27 and 12.7, respectively. At 273 K, the IAST selectivity of C2H2/CH4, C2H4/CH4, C2H6/CH4,C2H2/CO2 and CO2/CH4 are 88.4,47.5,24.9,11.5 and 9.7, respectively. At 298 K, the IAST selectivity are 44.4,42.2,14.7,7.9 and 6.8, respectively. At 273 K, due to introducing-COOH, the selectivities of C2H2/CH4 is higher than gas selectivity of ZJU-26a. And the selectivity value of CO2/CH4 of ZJU-72a is higher than that of PCN-306 without-COOH functional group. It indicated that introducing-COOH indeed improve selectivity of C2/C1, CO2/CH4 and C2H2/CO2 of MOFs. This research provides an important guiding role for highly effective gas sorption/separation MOFs materials.An new metal organic frameworks Cu2(FDDI)·Gx (ZJU-25; H4FDDI= 5,5’-(9H-fluorene-2,7-diyl)-diisophthalic acid; G= guest) was designed and synthesized. This new frameworks displays a rare topology of sty-a. Because of the bending of the H4FDDI linker, the structure of the material has changed. The surface area and porous volume increase compared with ZJU-26a and ZJU-72a. The BET of ZJU-25a is 2124 m2/g and porous volume is 1.183 cm3/g. At 300 K,35 bar and 65 bar, the absolute uptakes of methane for ZJU-25a are 180 cm3(STP)/cm3 and 227 cm3(STP)/cm3, respectively. The uptake of methane reaches the DOE target of 180 cm3(STP)/cm3 at 35 bar. To further demonstrate the feasibility for the practical separation, the breakthrough and pulse chromatographic experiments were simulated and the result showed that ZJU-25a has the ability of separating C2, C1 and CO2. The result indicated that ZJU-25a can recover each component in a nearly pure form for C2H2, C2H4, C2H6, CH4 and CO2. This research initiates the important experimental and theoretical basis for getting excellent comprehensive gas sorption/selective separation MOFs materials.Utilizing hexacarboxylate linker to construct a new MOFs material Cu6(CTIA)2 (ZJU-70; H6CTIA= 5,5’,5"-(9H-carbazole-3,6,9-triyl)triisophthalic acid) which has new network structure. The ZJU-70 does has high desity open metal sites and suitable pore spaces once it is suitably activated. Hence ZJU-70a has high adsorption capacity for C2H2 and CH4. At 298 K and 35 bar, ZJU-70a can take up CH4 of 178 cm3(STP)/cm3, which has reached the DOE target of 180 cm3(STP)/cm3. Transient breakthrough simulations were carried out to simulate the separation of C2H2/CO2 and CO2/CH4. The result indicated that ZJU-70a can completely separate C2H2/CO2 and CO2/CH4. This research provides a new design approach in order to achieve MOFs materials with high gas storage... |
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