| abstract |
A method is provided for separating olefins from non-olefins such as paraffins, including cycloparaffins, oxygenates and aromatics. The method allows for the separation of non-olefins using metal salts that form complexes with olefins by various methods, including decantation, distillation and gravity-based separation. The metals are dissolved or dispersed in an ionic liquid that has substantially no vapor pressure and hardly dissolves non-olefins. Thus, non-olefins can be cleanly phase separated and distilled without any ionic liquid being carried into the distillate. Preferred salts are salts of Group IB, more preferably silver salts. A preferred silver salt is silver tetrafluoroborate. Preferred ionic liquids are those that form stable solutions or dispersions of metal salts and do not dissolve non-olefins. Further, when the olefins are isomerized, the ionic liquid is preferably relatively non-acidic. The method involves forming a solution or dispersion of a suitable olefin complexing salt in a suitable ionic liquid. The olefin-containing mixture is contacted with an ionic liquid / salt solution to adsorb the olefins. After removing the paraffins, the olefins can be isolated by elimination. The olefin-containing mixture passes over / in the ionic liquid phase. The flow of the olefin-containing mixture on / in the ionic liquid can be, for example, cocurrent, countercurrent or multistage in a stirred tank. Countercurrent is preferred because it is the most efficient. The method can be optimized using combinatorial chemistry techniques. |