Structural Optimization of Interpenetrated Pillared-Layer Coordination Polymers for Ethylene/Ethane Separation

With the goal of achieving effective ethylene/ethane separation, we evaluated the gas sorption properties of four pillared-layer-type porous coordination polymers with double interpenetration, [Zn-2(tp)(2)(bpy)](n) (1), [Zn-2(fm)(2)(bpe)](n) (2), [Zn-2(fm)(2)(bpa)](n) (3), and [Zn-2(fm)(2)(bpy)](n) (4) (tp=terephthalate, bpy=4,4-bipyridyl, fm=fumarate, bpe=1,2-di(4-pyridyl)ethylene and bpa=1,2-di(4-pyridyl)ethane). It was found that 4, which contains the narrowest pores of all of these compounds, exhibited ethylene-selective sorption profiles. The ethylene selectivity of 4 was estimated to be 4.6 at 298K based on breakthrough experiments using ethylene/ethane gas mixtures. In addition, 4 exhibited a good regeneration ability compared with a conventional porous material.