Aromatics extraction through integration of complementary co-solvents

A solvent mixture for extractive distillation of an aromatics-containing stream consisting essentially of:

• a base solvent selected from the group consisting of sulfolane, N-methyl-pyrrolidone (NMP), N-formylmorpholine (NFM), dimethylformamide (DMF), a glycol derivative, or combinations there;
• a first co-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 co-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;
• optionally an additive;
• wherein the solvent mixture has a higher octane-to-benzene relative volatility than the base solvent in a combined benzene and octane feed at 125° C. and 3:1 solvent-to-feed weight ratio where a benzene weight ratio is higher than 30%.

A method of aromatics extraction comprising:

• introducing an aromatics-containing feed stream to an extractive distillation column at a feed stage;
• introducing a solvent mixture to the extractive distillation column at a stage above the feed stage, the solvent mixture consisting 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 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:
• recovering a bottoms stream comprising an aromatics-rich stream;
• and
• recovering an overhead stream comprising an aromatics-lean stream.