The results of the studies, carried out on the initial diesel distillates, and also raffinates and extracts, obtained by their extractive purification in the presence of ionic liquid on the basis of N-methylpyrrolidone and acetic acid as a selective solvent are presented. Hydrocarbon compositions of the raffinate and extract, obtained by selective purification of diesel distillate and its close-cut fractions has been determined by IR spectral analysis. Advantages and prospects of used ionic liquid have been presented in comparison with N-methylpyrrolidone in the processes of selective purification of diesel distillate.