Hydrocarbon Adsorption in the Flexible Metal Organic Frameworks MIL-53(Al, Cr)
Hydrocarbon Adsorption in the Flexible Metal Organic Frameworks MIL-53(Al, Cr)
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DOI：
10.1021/ja8039579
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发表时间：
2008-12-17
影响因子：
15
通讯作者：
Ferey, Gerard
中科院分区：
文献类型：
--
作者：
Trung, Thuy Khuong;Trens, Philippe;Ferey, Gerard
本文研究了正构烷烃在柔性金属有机骨架（MOF）MIL-53中的吸附。研究了烷基链长度（n = 1-9）、金属（Al、Cr）的性质和温度对反应的影响。吸附曲线的形状由正构烷烃的烷基链长度驱动。虽然传统的类型的等温线观察短链烷烃（n = 1，2），吸附与较长的链诱导明确的子步骤的等温线曲线，其位置取决于链长。这些子步骤是由于呼吸现象，证明了非原位X射线衍射分析。它们强烈地依赖于在孔隙中的吸附质的量和金属（Al，Cr）的性质，这对于给定的烷烃，导致强烈的变化，尽管两种金属的相似特性的子步骤的位置。吸附动力学对温度的微小变化高度敏感。他们在不同区域的等温线的详细分析表明，在某些情况下，存在不同的扩散制度和/或构象内的灵活的阶段。
A general study of the adsorption of n-alkanes in the flexible metal organic framework (MOF) MIL-53 is presented. The roles of the length of the alkyl chain (n = 1-9), the nature of the metal (Al, Cr), and temperature were investigated. The shape of the adsorption curves is driven by the alkyl chain length of the n-alkanes. While traditional typed isotherms are observed for short alkanes (n = 1, 2), adsorbates with longer chains induce clear substeps in the isotherm curves whose positions depend on the chain length. Such substeps are due to a breathing phenomenon, as proven by ex situ X-ray diffraction analysis. They strongly depend on the amount of adsorbate in the pores and on the nature of the metal (Al, Cr), which, for a given alkane, leads to a strong change in the substep positions despite the similar characteristics of the two metals. The adsorption kinetics are highly sensitive to small variations in temperature. Their detailed analysis in different regions of the isotherms shows in some cases the existence of distinct diffusion regimes and/or conformations within the flexible phases.