A Microporous Metal-Organic Framework for Gas-Chromatographic Separation of Alkanes

摘要

Microporous metal-organic frameworks (MOFs), which are new types of zeolite analogues, have been paid extensive attention because of their potential applications in gas storage, separation, and catalysis. The modular construction of MOFs allows their pore size and shape to be systematically tuned by the judicious choice of metal-containing secondary building units (SBUs) and/or bridging linkers, and by making use of framework interpenetration or interweaving. Their selective adsorption and high thermal stability make these microporous materials potentially useful for alkane separation. However, this application has not yet been developed. In the petroleum industry, the separation of alkane isomers is a very important process, and some narrow-pore zeolites have been used to sieve linear from branched alkanes, to boost octane ratings in gasoline. To match the alkane molecule sizes, the microporous compound Zn(BDC)(4,4-Bipy)0.5 (MOF-508; BDC=1,4-benzenedicarboxylic acid, 4,4-Bipy=4,4-bipyridine) was designed to have a primitive cubic framework with pores that can be tuned by double interpenetration to have 1D channels of approximately 4.0?.0 ? in cross section. Herein, we report the first example of a microporous MOF that is highly selective in the GC separation of alkanes.