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乙炔在工业和科学研究中非常重要,但其高活性(高纯乙炔的安全压缩压力小于2个大气压)限制了其存储与运输。此外,乙炔与二氧化碳具有相似的分子尺寸和物理性质,使得对其吸附分离变得困难。本项研究通过在多孔金属多氮唑框架(MAF)的孔道开口加入柔性侧基,获得了一个具有开关效应的新型多孔材料(MAF-2)。研究显示,合理的孔道表面结构加上柔性框架与动态侧基的协同效应,令MAF-2具备了独特的乙炔和二氧化碳吸附行为。该材料对乙炔的饱和吸附能力可达到119cm3g-1,而且常温常压下也可达到70cm3g-1。更重要的是,该材料的柔性行为使其吸附等温线不同于常规多孔材料。在实际应用条件下,MAF-2的乙炔吸附量随着压力增加而快速增加。在298K,1.0—1.5个大气压之间,MAF-2可以存储20倍其体积的乙炔,相当于同体积气体钢瓶有效储量的40倍。此外,在常温常压下,该材料具有非常高的乙炔/二氧化碳吸附比(3.7),可望应用于这两种气体的分离,并减少吸附分离过程中的能耗。
Acetylene is very important in industrial and scientific research but its high activity (safe compression pressure of high purity acetylene less than 2 atmospheres) limits its storage and transportation. In addition, acetylene and carbon dioxide have similar molecular size and physical properties, making it difficult to adsorb and separate them. In this study, a new porous material (MAF-2) with switching effect was obtained by adding flexible pendant groups to the pore openings of porous metal oxazole frame (MAF). Studies have shown that a reasonable pore surface structure combined with the synergistic effect of the flexible framework and dynamic side groups gives MAF-2 unique acetylene and carbon dioxide adsorption behavior. The material of acetylene saturation adsorption capacity can reach 119cm3g-1, but also under normal temperature and pressure can reach 70cm3g-1. More importantly, the material’s flexible behavior makes its adsorption isotherm distinct from conventional porous materials. Under practical conditions, the amount of acetylene adsorbed by MAF-2 rapidly increases with the increase of pressure. At 298K, 1.0-1.5 atmospheres, MAF-2 can store 20 times its volume of acetylene, which is equivalent to 40 times the effective reserves of the same volume of gas cylinders. In addition, the material has a very high acetylene / carbon dioxide adsorption ratio (3.7) at room temperature and atmospheric pressure and is expected to be used for the separation of these two gases and to reduce the energy consumption during the adsorption and separation.