Deep eutectic solvents based on glycerol as selective extractants for the recovery of aromatic hydrocarbons and petroleum acids from model fuel

The study set out to extract various types of hydrocarbons from model fuels using deep eutectic solvents based on glycerol. These solvents were synthesised by mixing glycerol as acting as a hydrogen bond donor with ammonium chloride or triethylammonium acetate [tea] [AcO]- acting as a hydrogen bond acceptor at room temperature in a volume ratio of 1:6. A mixture of n-decane and n-hexadecane was selected as components of the model fuel. For the extraction of mixtures of benzene, ethylbenzene (5%), p-, m-, o-cresol, fluorenone (3.5%) and petroleum acids (25%), these deep eutectic solvents were used at room temperature, as well as at a temperature of 60°C, and at atmospheric pressure. Extraction efficiency was evaluated by [1]NMR spectroscopy. The results demonstrated the complete single-stage extraction of p-, m- and o-cresols from the model fuel using the studied deep eutectic solvents. A deep eutectic solvent based on glycerol and triethylammonium acetate was found to have the highest extraction efficiency. The recovery rates for benzene, ethylbenzene, and fluorenone at room temperature are achieved in 3 hours of stirring (75, 25, and 53%, respectively). M- and o-cresols were fully recovered in 1 hour in a single step using a deep eutectic solvent based on triethylammonium acetate, while complete extraction of aromatic acids from a mixture of petroleum acids in model fuel was achieved using a deep eutectic solvent obtained by mixing ammonium chloride and glycerol.