The activity coefficients at infinite dilution, gamma(infinity)(13), for 60 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, acetic acid, thiophene, ethers, ketones, esters, butyraldehyde and acetonitrile in the ionic liquid 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate [BMPYR][FAP], were determined by gas-liquid chromatography at six temperatures in range of 318.15-368.15 K. The interaction of these 59 organic compounds and water with the IL was described with the partial excess molar Gibbs energies, Delta G(1)(E,infinity), enthalpies Delta H-1(E,infinity) and entropies T-ref Delta S-1(E,infinity) at infinite dilution, calculated from the experimental y(13)(infinity) values obtained over the temperature range. The gas-liquid partition coefficients. K-L were calculated for all solutes. The selectivities for different separation problems were calculated from gamma(infinity)(13) and compared to literature values for N-methyl-2-pyrrolidinone (NMP), sulfolane, and other tris(pentafluoroethyl)trifluorophosphate-based ionic liquids. Comparison with other 1-butyl-1-methylpyrrolidynium-based ILs shows much lower capability of [BMPYR][FAP] to reveal hydrogen bonds and interact with lone electron pairs and/or polar groups of solutes. In contrast with the former measured ILs,[BMPYR][FAP] was found to posses however very high capacity for benzene. The density of [BMPYR][FAP] in temperature range from 318.15 K to 368.15 K was measured. (C) 2011 Elsevier B.V. All rights reserved.