Gas Permeation in a Molecular Crystal and Space Expansion
Gas Permeation in a Molecular Crystal and Space Expansion
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分子晶体中的气体渗透和空间膨胀
DOI：
10.1021/ja501045u
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发表时间：
2014
影响因子：
15
通讯作者：
Y. Takasaki and S. Takamizawa
中科院分区：
文献类型：
--
作者：
Aiko Shitara;Takashi Koyama;Kana Goto;Yuya Shigenobu;Takuma Sugaya;Motohiko Sano;Hidehiro Kondo;Ikuo Hirono;Y. Takasaki and S. Takamizawa;Y. Takasaki and S. Takamizawa
合成了一种新型单晶膜[Cu（II）2（4-F-bza）4（2-mpyz）]n（4-F-bza = 4-氟苯甲酸酯; 2-mpyz = 2-甲基吡嗪），其在任何晶向上的渗透率在曲折修正中相同，证明气体在通道内扩散而不绕道。H_2的最小直径为2.6 μ m，比H_2（2.827 μ m）、CO（3.690 μ m）和CH_4（3.758 μ m）的Lennard-Jones直径小，具有较高的选择性（Fα：H_2/CO为23.5，H_2/CH_4为48.0），渗透率为1.18 × 10 ~（-12）mol m ~（-2）s ~（-1）Pa ~（-1）.高渗透率很好地解释了一个修改后的努森扩散模型的基础上的空间膨胀效应，这与所观察到的渗透选择性增强较小的气体在考虑膨胀的通道导致的气体分子或原子碰撞到通道壁。单晶X射线数据的分析表明，膨胀顺序为H2> Ar > CH 4，这是从渗透分析中预期的。多孔固体的选择渗透性取决于孔的弹性以及空通道的直径和目标气体的大小。
A novel single-crystal membrane [Cu(II)2(4-F-bza)4(2-mpyz)]n(4-F-bza = 4-fluorobenzoate; 2-mpyz = 2-methylpyrazine) was synthesized and its identical permeability in any crystal direction in the correction for tortuosity proved that gas diffuses inside the channels without detour. H2permeated by 1.18 × 10–12mol m m–2s–1Pa–1with a high selectivity (Fα: 23.5 for H2/CO and 48.0 for H2/CH4) through its 2D-channels having a minimum diameter of 2.6 Å, which is narrower than the Lennard-Jones diameter of H2(2.827 Å), CO (3.690 Å), and CH4(3.758 Å). The high rate of permeation was well explained by a modified Knudsen diffusion model based on the space expansion effect, which agrees with the observed permselectivity enhanced for smaller gases in considering the expansion of a channel resulting from the collision of gas molecules or atoms onto the channel wall. An analysis of single-crystal X-ray data showed the expansion order to be H2> Ar > CH4, which was expected from the permeation analysis. The permselectivity of a porous solid depends on the elasticity of the pores as well as on the diameter of the vacant channel and the size of the target gas.