Patent ID: 8536397

Claim:
A process for the recovery of a pure aromatics fraction containing benzene, toluene or xylene or mixtures of these aromatics from refinery streams or gasoline fractions as feed products containing such aromatics by way of extractive distillation, comprising: subjecting the feed product to a pre-distillation in a first process step prior to the extractive distillation, where the components which boil at higher temperatures than the mentioned aromatics are separated as a bottom product, and mixing the thus obtained starting mixture containing aromatics in a second process step with an extracting solvent or solvent mixture which is capable of selectively increasing the fugacity of the non-aromatic components of the starting mixture and thus the separating efficiency, and submitted to an extractive distillation, and distilling the extracting solvent from the obtained extract off in a third process step for the separation of the extracting solvent by increasing the temperature or increasing the temperature and reducing the pressure, wherein the extractive distillation of the second process step is carried out using a solvent combination comprising N,N′-diformyl piperazine with another solvent or using a solvent combination of 2,2′-bis-(cyanoethyl)ether with N,N′-diformyl piperazine or N-formyl morpholine as a vapour-pressure changing solvent combination.