Ionic liquids of the general formula C+A− where C+ represents an organic cation, specifically, but not limited to the imidazolium, pyridinium, isoquinolinium, ammonium types, which have aliphatic and aromatic substituents, while A− represents a carboxylate, aromatic and aliphatic anion. The ionic liquids are synthesized under conventional heating or microwave irradiation This invention is also related to the application of ionic liquids to remove sulfur compounds of naphthas through a liquid-liquid extraction and the recovery and reuse of ionic liquids by the application of heat, reduced pressure and washing with solvents.