Abstract: Solvent mixtures for extractive distillation are described. One solvent mixture consists essentially of: a first solvent having a higher octane-to-benzene relative volatility than sulfolane in a 90% benzene 10% octane feed mixture at 150° C. and 24:1 solvent-to-feed weight ratio; a second solvent having a higher octane-to-benzene relative volatility than sulfolane in a 50% benzene 50% octane feed mixture at 150° C. and 3:1 solvent-to-feed weight ratio; and optionally an additive; wherein the solvent mixture has a higher octane-to-benzene relative volatility than Sulfolane in a combined benzene and octane feed at 125° C. and 3:1 solvent-to-feed weight ratio wherein a benzene weight ratio is higher than 30%. Another solvent mixture consists essentially of: a base solvent selected from the group consisting of sulfolane, N-methyl-pyrrolidone (NMP), N-formylmorpholine (NFM), dimethylformamide (DMF), glycol derivatives, or combinations there along with first and second co-solvents.