Patent ID: 8362314

Claim:
A process for obtaining aromatic hydrocarbons selected from benzene, toluene, xylene and ethylbenzene mixtures thereof from a hydrocarbon mixture which additionally comprises nonaromatic hydrocarbons and high boilers, comprising the steps of (A) providing a hydrocarbon mixture al and an extractive solvent a2 composed of N-formylmorpholine, (B) extractively distilling the hydrocarbon mixture a 1 with the extractive solvent to obtain a mixture b1 of extractive solvent and the aromatic hydrocarbons, said mixture comprising high boilers, and a mixture b2 comprising nonaromatic hydrocarbons, (C) distilling the mixture b1 of extractive solvent and aromatic hydrocarbons obtained in step (B) to obtain one or more fractions c1 composed of aromatic hydrocarbons and the extractive solvent c2 which comprises high boilers, (D) removing a substream d1 from the extractive solvent c2 and recycling the extractive solvent c2 into the extractive distillation (B), (E) extracting the substream d1 of the extractive solvent with water to obtain an aqueous extract phase el essentially free of high boilers and an organic phase e2 comprising the high boilers, (F) distilling the aqueous extract phase e1 and recovering the extractive solvent a2 in purified form, and recycling the extractive solvent into the extractive distillation (B), which comprises preceding performance of step (E) with performance of a distillation in which a fraction composed of very high-boiling hydrocarbons which have a boiling point above 240° C. at standard pressure or cannot be distilled at all without decomposition, is removed from the substream d1 of the extractive solvent.