Selective Hysteretic Sorption of Light Hydrocarbons in a Flexible Metal–Organic Framework Material

Shan Gao,Harry G W Godfrey,Sihai Yang,Chiu C Tang,Zhenzhong Lu,Claire Murray,K Mark Thomas,Martin Schröder,Yong Yan,Christopher G Morris

doi:10.1021/acs.chemmater.6b00443

Abstract

Porous MFM-202a (MFM = Manchester Framework Material, replacing the NOTT designation) shows an exceptionally high uptake of acetylene, 18.3 mmol g–1 (47.6 wt %) at 195 K and 1.0 bar, representing the highest value reported to date for a framework material. However, at 293 K and 10 bar C2H6 uptake (9.13 mmol g–1) is preferred. Dual-site Langmuir-Freundlich (DSLF)- and Numerical Integration (NI)-based IAST methods have been used to analyze selectivities for C1 to C3 hydrocarbons. MFM-202a exhibits broadly hysteretic desorption of acetylene; such behavior is important for practical gas storage since it allows the gas to be adsorbed at high pressure but stored at relatively low pressure. Stepwise uptake and hysteretic release were also observed for adsorption of other unsaturated light hydrocarbons (ethane and propene) in MFM-202a but not for saturated hydrocarbons (methane, ethane, and propane). MFM-202a has been studied by in situ synchrotron X-ray powder diffraction to reveal the possible phase transition ...

Highlights

The large-scale separation of hydrocarbon mixtures for the production and purification of relevant energy resources and feedstocks is an extremely energy-consuming process
The state-of-the-art separation method for light hydrocarbon mixtures is cryogenic distillation at high pressure based upon the small differences in vapor pressure for each component.[4]
All chemical reagents were used as received from commercial suppliers without further purification

Summary

Introduction

The large-scale separation of hydrocarbon mixtures for the production and purification of relevant energy resources and feedstocks is an extremely energy-consuming process. The purification of two very important industrial starting petrochemicals, ethene and propene (the former being the largest volume organic in the world), involves the removal of other light hydrocarbons (e.g., acetylene, ethane, and propane).[3] The state-of-the-art separation method for light hydrocarbon mixtures is cryogenic distillation at high pressure based upon the small differences in vapor pressure for each component.[4] This process is highly energy-intensive, and reductions in cost and energy consumption are required. Selective adsorption by traditional porous materials (e.g., mesoporous silica, zeolites, and activated carbon) as adsorbents have been employed to separate hydrocarbon mixtures.[5−8]

Methods

Results

Conclusion