Extraction distillation of hydrocarbon mixtures of varying unsaturation

Claim 1

A PROCESS FOR THE SEPARATION OF MIXTURES OF HYDROCARBONS OF VARYING DEGREES OF UNSATURATION HAVING NO GREATER THAN 7 CARBON ATOMS PER MOLECULE WHICH COMPRISES EXTRACTIVELY DISTILLING SAID MIXTURES IN THE PRESENCE OF A SOLVENT COMPRISING 50 TO 90 PERCENT BY WEIGHT OF FURFURAL, 0.1 TO 10 PERCENT BY WEIGHT OF DIMER, OIL, SAID DIMER OIL CONSISTING ESSENTIALLY OF DI-ETHYLENICALLY UNSATURATED HYDROCARBONS HAVING A NUMBER OF CARBON ATOMS APPROXIMATELY TWICE THAT OF THE MORE UNSATURATED HYDROCARBONS CONTAINED IN SAID MIXTURES, 5 TO 20 PERCENT BY WEIGHT OF WATER, AND 5 TO 20 PERCENT BY WEIGHT OF A PARTIALLY WATER-SOLUBLE ALCOHOL SELECTED FROM THE GROUP CONSISTING OF AROMATIC ALCOHOLS, HETEROCYCLIC ALCOHOLS AND ALIPHATIC ALCOHOLS, RECOVERING AN OVERHEAD DISTILATE FRACTION FROM SAID DISTILLATION SUBSTANTIALLY RICHER IN HYDROCARBONS OF A LESSER DEGREE OF UNSATURATION THAN SAID ORIGINAL MIXTURE, REMOVING THE SOLVENT FRACTION RICH IN THE MORE UNSATURATED HYDROCARBONS OF SAID MIXTURE FROM SAID DISTILLATION AND RECOVERING FROM SAID RICH SOLVENT A FRACTION SUBSTANTIALLY RICHER IN SAID MORE UNSATURATED HYDROCARBONS.