Process for the purification of a feedstock comprising ethanol, acetaldehyde and impurities by a solvent, known as Lewis donor solvent: - a stage A) of counter-currentwise liquid-liquid extraction fed at the top by the said feedstock as a mixture with the raffinate resulting from the re-extraction stage B), this mixture constituting the feed of the said stage A), and at the bottom by the effluent rich in Lewis donor solvent resulting from the regeneration stage C), a contribution of Lewis donor solvent optionally being mixed with the said effluent rich in Lewis donor solvent, and producing an extract at the top and a purified feedstock at the bottom, carried out at a temperature of between 10 and 70°C and at a pressure of between 0.1 and 0.5 MPa, with a flow rate by weight of continuous phase/flow rate by weight of disperse phase ratio of less than 70; - a stage B) of counter-current liquid-liquid re-extraction fed at the top by an auxiliary solvent and at the bottom by the extract resulting from stage A), and producing an extract at the top and a raffinate at the bottom, the said raffinate feeding the said stage A), carried out at a temperature of between 10 and 70°C and at a pressure of between 0.1 and 0.5 MPa, with a flow rate by weight of continuous phase/flow rate by weight of disperse phase ratio of less than 70; - a stage C) of regeneration in which the extract resulting from stage B) is separated by a first distillation into a distillate rich in light impurities and a residue which undergoes a second distillation, which produces an effluent rich in Lewis donor solvent at the top and a residue rich in heavy impurities; characterized in that the said Lewis donor solvent comprises a Lewis donor chosen from the group consisting of unsaturated fatty acids having between 12 and 18 carbon atoms, phosphate esters having between 12 and 30 carbon atoms and their mixtures. - a stage A) of counter-currentwise liquid-liquid extraction fed at the top by the said feedstock as a mixture with the raffinate resulting from the re-extraction stage B), this mixture constituting the feed of the said stage A), and at the bottom by the effluent rich in Lewis donor solvent resulting from the regeneration stage C), a contribution of Lewis donor solvent optionally being mixed with the said effluent rich in Lewis donor solvent, and producing an extract at the top and a purified feedstock at the bottom, carried out at a temperature of between 10 and 70°C and at a pressure of between 0.1 and 0.5 MPa, with a flow rate by weight of continuous phase/flow rate by weight of disperse phase ratio of less than 70; - a stage B) of counter-current liquid-liquid re-extraction fed at the top by an auxiliary solvent and at the bottom by the extract resulting from stage A), and producing an extract at the top and a raffinate at the bottom, the said raffinate feeding the said stage A), carried out at a temperature of between 10 and 70°C and at a pressure of between 0.1 and 0.5 MPa, with a flow rate by weight of continuous phase/flow rate by weight of disperse phase ratio of less than 70; - a stage C) of regeneration in which the extract resulting from stage B) is separated by a first distillation into a distillate rich in light impurities and a residue which undergoes a second distillation, which produces an effluent rich in Lewis donor solvent at the top and a residue rich in heavy impurities; characterized in that