Abstract: A method for the removal of aromatic hydrocarbon from mixtures containing non-aromatic hydrocarbon by liquid-liquid extraction and extractive distillation is described. Isoenthalpic expansion of the rectification column bottom solvent stream and addition of water to the selective solvent can be used to reduce heat consumption.

Abstract: For refining spent motor oils in order to recover lubricating bases to be reused, the stock to be refined is first stripped of water and light hydrocarbons, then a first extraction with a solvent (preferably a lower paraffin), heating the oil stripped of the solvent, distilling it under vacuum to separate light, medium and heavy lubricating bases, heating the heavier lubricating base and then extracting it with the same solvent as aforesaid, and sending the lubricating bases, separately and individually, to a hydrofinishing stage. The recycle to solvent extraction of the heavy bases affords the advantage of important heat savings and the possibility of adopting blander working conditions in the hydrofinishing of the heavier lubricating bases.