Extraction of Sulphur-Containing and Polycyclic Aromatic Compounds of Diesel Fuel with Imidazole-Containing Ionic Liquids

The extraction of sulphur-containing compounds of diesel fuel (DF) with ionic liquids (IL) based on imidazole with various substituents (butyl, octyl, nonyl, dodecyl, cetyl) in position 1 of the imidazole ring has been studied; the composition of sulphur-containing compounds and polycyclic aromatic hydrocarbons (PAH) has been determined by gas chromatography - mass spectrometry in the initial and purified diesel fuel. The optimal extraction conditions are determined: temperature 30-35 degrees C, extraction time 60 min, DF/IL ratio 1.66-2. The most effective extractant for the sulphur-containing compounds of DF is 1-nonyl-3-methylimidazolium bromide, which allows reducing the total sulphur content from 0.369 to 0.143 wt%. Results of the studies of group and individual composition of dibenzothiophene (DBT) and PAH derivatives show that the degree of extraction of DBT derivatives and tricyclic aromatic hydrocarbons is 66-72 %. Naphthalene and its homologues are extracted to a lesser extent - 37 %. Among DBT homologues, dimethyldibenzothiophene is extracted most completely.