Screening metal-organic frameworks for separation of pentane isomers

This article compares the performances of several metal-organic frameworks (MOFs) and zeolitic imidazolate frameworks (ZIFs) for the separation of pentane isomers: n-pentane (nC5), 2-methylbutane (2MB), and 2,2-dimethylpropane (= neo-pentane (neo-P)) in fixed bed adsorbers. The required input data on unary and mixture adsorption equilibria are obtained from Configurational-Bias Monte Carlo (CBMC) simulations for twelve different adsorbents. The best separation performance is realized with Fe₂(BDP)₃, where BDP^2- = 1,4-benzenedipyrazolate, a MOF with triangular shaped 4.9 Å channels that affords the ideal pore topology to differentiate between the three pentane isomers; the linear nC5 aligns commensurately with the pore landscape. Using transient breakthrough simulations in fixed bed adsorbers, the separation performance of Fe₂(BDP)₃ is found to be significantly superior to that of other materials.