Betaine plus (Glycerol or Ethylene Glycol or Propylene Glycol) Deep Eutectic Solvents for Extractive Purification of Gasoline

Deep eutectic solvents (DES), a class of ' green ' solvents, are being tested for extractive desulfurization, denitrification and dearomatization of fuels. Here, three DESs were prepared by combining betaine (B) with glycerol (Gly), ethylene glycol (EG) or propylene glycol (PG) in the molar ratios of 1:3, 1:3 and 1:3.5, respectively. The DESs were used for the removal of thiophene, pyridine and toluene from a 6-component model gasoline and for the removal of sulfur and nitrogen compounds from a real fluid catalytic cracking (FCC) gasoline. Physical properties of the prepared DESs - density, viscosity, refractive index, specific conductance, thermal conductivity, temperature diffusivity and heat capacity were determined, too. All tested DESs exhibit higher potential for denitrification of model fuel with respect to desulfurization and dearomatization. B-PG 1:3.5 worked best in one-stage denitrification of both model gasoline (similar to 80%) and real FCC gasoline (similar to 36%). The reuse of solvent without loss in extraction efficiency in four extraction stages was successfully achieved for all three DESs by evaporation purification of DES between the stages.