INS Studies of inversed alkane and alkene separation by metal-organic frameworks

Global production of olefins currently exceeds that of any other chemicals. This process involves the cracking of long-chain hydrocarbons into short-chain (C1-C3) ones, with ethylene and propene being especially valuable to the polymer industry. The coexistence of olefins and paraffins with similar physical properties in the crude product are extremely challenging for their separation. The current technology replies heavily on cryogenic separation, which is extremely energy-intensive and causes nearly 2% of global CO2 emission. We have recently developed two ultramicroporous robust metal-organic frameworks (MOFs), namely Cu-DMP and Al-BTCA, which show highly unusual selective alkane adsorption (vs alkenes), a desired feature for practical applications. To gain insights into their exceptional separation capabilities, we request 5 days on TOSCA to investigate the host-guest interaction of C2 and C3 alkenes and alkanes within these MOFs via in situ inelastic neutron scattering technique to understand their unusual sorption selectivity.

目前，全球烯烃（olefins）的总产量已超越其他所有品类的化学品。该生产过程涉及将长链烃类裂解为短链（C1-C3）烃类产物，其中乙烯与丙烯对聚合物工业而言具有极高的应用价值。粗产物中烯烃（olefins）与烷烃（paraffins）物理性质相近且共存，使得二者的分离极具挑战性。当前的分离技术高度依赖低温分离工艺，该工艺能耗极高，全球二氧化碳排放量中近2%均来自此类操作。我们近期开发了两款超微孔稳定金属有机框架（metal-organic frameworks, MOFs），分别为Cu-DMP与Al-BTCA，二者展现出极不寻常的烷烃选择性吸附性能（相较于烯烃），这一特性恰好契合实际工业应用的需求。为深入探究这两款材料优异的分离性能，我们申请在TOSCA谱仪上开展为期5天的实验，通过原位非弹性中子散射（in situ inelastic neutron scattering）技术，研究C2、C3烯烃与烷烃在这些MOFs内部的主客体相互作用，以阐明其反常的吸附选择性机制。