Abstract:
Adsorptive separation by porous solids provides an energy-efficient alternative for the purification of important chemical species compared to energy-intensive distillations. Particularly, the separation of linear hexane isomers from its branched counterparts is crucial to produce premium grade gasoline with high research octane number (RON). Herein, we report the synthesis of a new, flexible zinc-based metal-organic framework, [Zn5(μ3-OH)2(adtb)2(H2O)5·5 DMA] (Zn-adtb), constructed from a butterfly shaped carboxylate linker with underlying (4,8)-connected scu topology capable of separating the C6 isomers nHEX, 3MP, and 23DMB. The sorbate-sorbent interactions and separation mechanisms were investigated and analyzed through in situ FTIR, solid state NMR measurements and computational modeling. These studies reveal that Zn-adtb discriminates the nHEX/3MP isomer pair through a kinetic separation mechanism and the nHEX/23DMB isomer pair through a molecular sieving mechanism. Column breakthrough measurements further demonstrate the efficient separation of linear nHEX from the mono- and dibranched isomers.
摘要:
与能源密集型蒸馏相比,多孔固体的吸附分离为纯化重要化学物质提供了节能的替代方法。特别是,直链己烷异构体与支链己烷异构体的分离对于生产具有高研究辛烷值(RON)的高级汽油至关重要。在这里,我们报告了一种新的合成,柔性锌基金属有机骨架,[Zn5(μ3-OH)2(adtb)2(H2O)5·5DMA](Zn-adtb),由具有能够分离C6异构体nHEX的底层(4,8)连接的scu拓扑结构的蝶形羧酸酯接头构建而成,3MP,23DMB通过原位红外光谱研究和分析了吸附剂与吸附剂的相互作用和分离机理,固态核磁共振测量和计算建模。这些研究表明,Zn-adtb通过动力学分离机制区分nHEX/3MP异构体对,通过分子筛分机制区分nHEX/23DMB异构体对。柱穿透测量进一步证明了线性nHEX与单支化异构体和二支化异构体的有效分离。