Image courtesy of Jeff Long, University of California, Berkeley
Crystal structure of the gas-separating MOF Fe2(dobdc) from neutron diffraction, showing an ethylene molecule bound to the open coordination site at each iron center. The open coordination site at each iron center preferentially binds unsaturated hydrocarbons like ethylene (shown), propylene, and acetylene.
Experiments confirm theoretical predictions of a novel metal-organic framework (MOF) material that purifies several industrially important gases at nearly ambient conditions.
The discovery could save the oil and chemical industries money and lower their environmental impacts by replacing existing large-scale energy-intensive gas separation processes.
Scientists at the University of California, Berkeley–based EFRC, the Center for Gas Separation Relevant to Clean Energy Technologies, have experimentally confirmed the theoretical predictions that a novel metal-organic framework (MOF) material could purify several industrially important gases at nearly ambient conditions. MOFs are crystalline compounds consisting of metal clusters attached to organic molecules to form porous structures. Neutron diffraction of the MOF reveals a large surface area and exposed iron cation sites, which can preferentially adsorb unsaturated hydrocarbon molecules. It exhibits excellent performance for the purification of hydrocarbon gases, such as methane, ethylene, and propylene, useful for fuels and plastics, from gas mixtures at conditions much milder than those currently used for the separation of these gases. This patented discovery could result in cost savings for the oil and chemical industries and lower their environmental impacts by replacing existing large-scale energy-intensive gas separation processes. Current production involves cracking longer chain hydrocarbons at high temperatures (up to 500-600 °C) and separating the resulting products at high pressures and cryogenic temperatures (-100 °C). This material may also be capable of purifying natural gas streams containing a number of impurity gases.
Jeffrey R. Long
University of California, Berkeley
Director of the Center for Gas Separations Relevant to Clean Energy Technologies (CGS) EFRC
Office of Science Basic Energy Sciences program, Energy Frontier Research Centers program; Neutron scattering was performed a the National Institute of Standards and Technology (NIST); and a NIST National Research Council Postdoctoral Fellowship (W.L.Q).
Bloch, E. D. et al. “Hydrocarbon Separations in a Metal-Organic Framework with Open Iron(II) Coordination Sites” Science 335 1606-1610 (2012). [DOI: 10.1126/science.1217544]
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