陈小明院士团队Science：MOF膜高效分离1,3-丁二烯

— 前言 —

1，3-丁二烯是重要的聚合物高分子的单体。在发生聚合之前，从丁烷，丁烯和异丁烯其他C4碳氢混合物中分离必须通过耗能较高的萃取分馏过程。多孔材料用于气体分离过程的机制一般基于分子尺寸，形状，极性，极化率以及配位能力。但是对于1，3-丁二烯与其它C4碳氢混合物，这些分离机制也难以实现单组份的分离。

— 图 快解—

Fig. 1 不同柔性客体分子的不同吸附机制。Strategy for differential adsorption of flexible guests. (A)Controlling the guest conformations by variation of the pore size, shape, anddimensionality. E, energy. (B) PDFT-derived thermodynamicenergies for adsorption of C4 hydrocarbons in Zn-BTM. Blacklines highlight the energy trends for the four guests, in which the lowestenergy among all possible conformations of a guest was selected, as required bythe thermodynamic principle.

Fig. 2 Mixture breakthrough curves for C4 hydrocarbons. (A)Zr-BDC, (B) Cu-SiF6, (C) Zn-BTA, and (D) Zn-BTMcurves for a 1:1:1:1 C4H6/n-C4H8/i-C4H8/C4H10 mixture.(E) Zn-BTM and (F) Zn-EIM-RHO curves for a 5:2:2:1 C4H6/n-C4H8/i-C4H8/C4H10 mixture. Ci and Co arethe concentrations of each gas at the inlet and outlet, respectively. Lines aredrawn to guide the eye. Dashed lines highlight the gas composition at 0.5%,corresponding to the composition of other gases at 99.5%. The insets showframework and pore surface structures of the adsorbent.

Fig. 3 Zn-BTM单组份气体吸附性质。Single-component gas adsorption properties of Zn-BTM. (A)Adsorption isotherms for C4H6, n-C4H8, i-C4H8,and C4H10in Zn-BTM at 298 K. Lines are drawn to guide theeye. (B) The coverage-dependent C4H6, n-C4H8, i-C4H8,and C4H10adsorption enthalpies were calculated by theClausius-Clapeyron equation using original data without fitting (points) orusing data fitted by the Langmuir-Freundlich equation (lines). Qst,adsorption enthalpy; n, guest loading.

Fig. 4 单晶X射线确定的主-客体结构。Single-crystal x-ray host-guest structures. (A) C4H6, (B) n-C4H8,(C) i-C4H8, and (D) C4H10.The guest molecules are shown in yellow as ball-and-stick models, and the hostframeworks are shown as stick models with Zn in purple, C in gray, and N inblue. The methyl groups and hydrogen atoms are omitted for clarity. Strong(H···N < 2.3 ?), weak (2.3 ? < H···N < 2.8 ?), and very weak (2.8 ?< H···N < 3.5 ?) C–H···N interactions are displayed as red, green, andblack dashed lines, respectively.

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