Krupp Koppers Gmbh

Wilhelm Huwels

Gerhard Preusser

Martin Schulze

Klaus Richter

Process for recovering highly pure aromatic substances from mixtures of hydrocarbons which contain in addition to the aromatic substances, large amounts of non-aromatic substances by liquid-liquid extraction in combination with an after arranged extractive distillation whereby the liquid-liquid extraction of the starting hydrocarbon mixture is carried out under such conditions that the resulting extract contains substantially the total amount of the aromatic substances and a portion of the non-aromatic substances, introducing this extract into an after arranged extractive distillation for further separating said extract whereby the sump product (extract phase) formed is drawn off and introduced into an after arranged distillation column where it is separated into an aromatic and a solvent fraction, while the head product of the extractive distillation (raffinate phase) is reintroduced into the bottom of the extractor for liquid-liquid extraction thereof, wherein there is used in both of the extracting stages, as selective solvent, morpholine and/or N-substituted morpholine in admixture with water whereby the water content of the solvent for the liquid-liquid extraction amounts to between 2-15 weight percent and for the extractive distillation amounts to between 0 and 8 weight percent.

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Essen, Germany

Wilhelm Huwels