The activity coefficients at infinite dilution, gamma(infinity)(13), for 37 solutes, alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, and water, in the ionic liquid 1-(3-hydroxypropyl)pyridinium trifluorotris(perfluoroethyl)phosphate [N-C3OHPY][FAP] were determined by gas liquid chromatography at the temperatures from 308.15 to 358.15 K. The partial molar excess enthalpies at infinite dilution values Delta H-1(E,infinity) were calculated from the experimental gamma(infinity)(13) values obtained over the temperature range. The selectivities for aliphatics/aromatics hydrocarbons separation problem were calculated from the gamma(infinity)(13) values and compared to the literature values for other ionic liquids, N-methylpyrrolidone (NMP) and sulfolane. It was found that the investigated [N-C3OHPY][FAP] ionic liquid shows much higher selectivity and capacity at infinite dilution than the generally used organic solvents such as NMP, sulfolane, and other ionic liquids.