This paper describes the extraction of C-5-C-8 linear alpha-olefins from olefin/paraffin mixtures of the same carbon number via a reversible complexation with a silver salt (silver bis(trifluoromethylsulfonyl)imide, Ag[Tf2N]) to form room temperature ionic liquids [Ag(olefin)(x)][Tf2N]. From the experimental (liquid + liquid) equilibrium data for the olefin/paraffin mixtures and Ag[Tf2N], 1-pentene showed the best separation performance while C-7 and C-8 olefins could only be separated from the corresponding mixtures on addition of water which also improves the selectivity at lower carbon numbers like the C-5 and C-6, for example. Using infrared and Raman spectroscopy of the complex and Ag[Tf2N] saturated by olefin, the mechanism of the extraction was found to be based on both chemical complexation and the physical solubility of the olefin in the ionic liquid ([Ag(olefin)(x)][Tf2N]). These experiments further support the use of such extraction techniques for the separation of olefins from paraffins. Crown Copyright (C) 2014 Published by Elsevier Ltd. All rights reserved.