perstraction

CONT: Abstract of the disclosure. Membrane separation under perstraction conditions of a lube oil distillate is disclosed which produces a retentate rich in non-aromatics hydrocarbons and alkyl aromatic and a permeate rich in multi-ring aromatics. The recovered retentate is similar to a solvent extracted raffinate but possesses a higher concentration of alkyl-single ring aromatics. The membrane separation process is highly selective for removing multi-ring aromatics from the lube distillate.