Optimized Separating Acetylene from Carbon Dioxide and Ethylene in a Microporous Material

Published

June 15, 2017

Author(s)

Rui-Biao Lin, Libo Li, Hui Wu, Hadi Arman, Bin Li, Rong-Guang Lin, Wei Zhou, Banglin Chen

Abstract

Selective separation of acetylene (C₂Hd2^)from carbon dioxide (CO₂) or ethylene (C₂H₄) needs specific porous materials whose pores can realize sieving effects while pore surfaces can differentiate their recognitions for these molecules of similar molecular sizes and physical properties. We report a microporous material [Zn(dps)₂(Sif₆)] (UTSA-300, dps = 4,4'-dipyridylsulfide) with two-dimensional channels of about 3.3 angstram}, well-matched for the molecular sizes of C₂H₂. After activation, the network was transformed to its closed phase UTSA-300a with dispersed 0D cavities, accompanied by conformation change of the pyridyl ligand and rotation of Sif₆^2-^ pillars. Strong C-H...F and π-π stacking interactions are found in closed UTSA-300a, resulting shrinkage of the structure. Interestingly, UTSA-300A takes up quite high amount of acetylene (76.4 cm₃ g^-1), while shows complete C₃H₄ and CO₂ exclusion from C₂H₂ under ambient conditions. Neutron powder diffraction and molecule modeling studies clearly reveal that C₂H₂ molecule primarily bind two hexafluorosilicate F atoms in a head-on orientation, breaking the original intra-network hydrogen bonding and subsequently expanding to opened structure. Crystal structures, gas sorption isotherms, molecular modeling, experimental breakthrough experiment and selectivity calculation comprehensively demonstrated this unique MOF material for the highly selective C₂H₂/CO₂ and C₂H₂.C₂H₄ separation.

Citation

Journal of American Chemical Society

Volume

139

Issue

23

Pub Type

Journals

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Keywords

gas separation, metal-organic framework

Citation

Lin, R. , Li, L. , Wu, H. , Arman, H. , Li, B. , Lin, R. , Zhou, W. and Chen, B. (2017), Optimized Separating Acetylene from Carbon Dioxide and Ethylene in a Microporous Material, Journal of American Chemical Society, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=923567 (Accessed September 7, 2024)