Comparison of the behavior of metal-organic frameworks and zeolites for hydrocarbon separations.
Comparison of the behavior of metal-organic frameworks and zeolites for hydrocarbon separations.
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DOI：
10.1021/ja211864w
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发表时间：
2012-03
影响因子：
15
通讯作者：
D. Peralta;G. Chaplais;A. Simon‐Masseron;K. Barthelet;C. Chizallet;A. Quoineaud;G. Pirngruber
中科院分区：
文献类型：
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作者：
D. Peralta;G. Chaplais;A. Simon‐Masseron;K. Barthelet;C. Chizallet;A. Quoineaud;G. Pirngruber
本工作的目的是研究最重要的烃类化合物在金属有机骨架(MOF)上的吸附和分离，并与沸石进行比较。为此，我们选择了四个探针分子，每个分子代表这些家族中的一个，即邻二甲苯和对二甲苯作为芳烃，1-辛烯作为烯烃，正辛烷作为烷烃。通过二元穿透实验研究了这四种分子的分离。为了表示MOF结构的多样性，实验使用了(I)两个配位不饱和金属中心(CU)的MOF，即CuBTC(HKUST-1)和CPO-27-Ni，(Ii)具有阴离子骨架和骨架外阳离子的MOF，即Rho-ZMOF，和(Iii)两种具有不同孔径的非极性沸石咪唑骨架(ZIF-8和ZIF-76)。用NaY分子筛和β分子筛分别作为极性和非极性参比吸附剂。研究结果可以概括如下：ZIF(不带任何极性官能团)表现出非极性吸附剂的行为，并表现出非常有趣和意想不到的分子筛分性质。CuS-MOF的行为类似于极性吸附剂，但表现出优先选择烯烃而不是芳烃的特性。多亏了DFT+D计算，该功能变得更加合理。具有骨架外阳离子的MOF的行为类似于极性(阳离子)沸石。
The objective of this work was to study the adsorption and separation of the most important families of hydrocarbon compounds on metal-organic frameworks (MOFs), in comparison with zeolites. For this purpose, we have selected four probe molecules, each of them representing one of these families, i.e., o- and p-xylene as aromatics, 1-octene as an alkene, and n-octane as an alkane. The separation of these four molecules was studied by binary breakthrough experiments. To represent the large diversity of MOF structures, the experiments were carried out with (i) two MOFs with coordinatively unsaturated metal sites (CUS), i.e., Cu-btc (HKUST-1) and CPO-27-Ni, (ii) a MOF with an anionic framework and extraframework cations, i.e. RHO-ZMOF, and (iii) two rather apolar zeolitic imidazolate framework (ZIF) materials with different pore sizes, i.e. ZIF-8 and ZIF-76. Zeolite NaY and zeolite β were used as polar and apolar reference adsorbents, respectively. The results can be briefly summarized as follows: ZIFs (not carrying any polar functional groups) behave like apolar adsorbents and exhibit very interesting and unexpected molecular sieving properties. CUS-MOFs behave like polar adsorbents but show the specificity of preferring alkenes over aromatics. This feature is rationalized thanks to DFT+D calculations. MOFs with extraframework cations behave like polar (cationic) zeolites.