Designing ionic liquids to enhance ethylene/ethane separations

Complexation of ethylene through its double bond with silver and copper ions has been used in the literature for chemical separation of olefins and paraffins. However, other components of raw gas feeds, such as acetylene, can react with the silver and become explosive. This has prevented the uptake of these materials into large scale processes.The objective of this work is to develop and try to create new chemisorbent materials for the separation of light olefins and paraffins; to achieve high capacity combined with selectivity for ethylene.

Several groups of ionic liquids have been investigated including phosphorous containing ionic liquids, nitrile based ionic liquids (including cyanopyridinium ionic liquids) and ionic liquids mixed with metal species. This will involve the investigation of ethylene and ethane solubility and interactions in these ionic liquids, using characterisation studies including nuclear magnetic resonance spectroscopy (1D/2D spectras), thermal analysis, and viscosity/density measurements.