Recovery of furfural in extractive distillation purification of cyclic hydrocarbons

Claim 1

IN A PROCESS OF SEPARATING A C6-C7 CYCLIC HYDROCARBON FROM A MIXTURE CONTAINING C7-C8 ALIPHATIC HYDROCARBONS BOILING IN THE RANGE OF 80* TO 125* C. BY EXTRACTIVE DISTILLATION IN THE PRESENCE OF WATER-FREE FURFURAL AS SOLVENT, THE STEPS WHICH COMPRISE ADDING WATER TO OVERHEAD HYDROCARBON DISTILLATE OF THE EXTRACTIVE DISTILLATION TO FORM AQUEOUS WASH LIQUID, REMOVING FURFURAL IN SAID AQUEOUS WASH LIQUID FROM RAFFINATE HYDROCARBONS DISTILLED OVERHEAD FROM THE EXTRACTIVE DISTILLATION ZONE, STRIPPING FURFURAL FROM THE WASH LIQUID TO OBTAIN A SLIGHTLY AQUEOUS CONCENTRATE OF THE FURFURAL CONTAINING ABOUT 95 WEIGHT PERCENT FURFURAL AND 5 WEIGHT PERCENT OF WATER, PASSNG SAID CONCENTRATE OF THE FURFURAL TO AN UPPER PART OF AN EXTRACT STRIPPING ZONE WHEREIN THE CYCLIC HYDROCARBON IS FRACTIONALLY DISTILLED FROM FURFURAL EXTRACT FORMED BY THE EXTRACTIVE DISTILLATION, THEREBY OBTAINING WATER-FREE FURFURAL BOTTOMS PRODUCT IN SAID EXTRACT STRIPPING ZONE, AND REUSING THE SAID WATER-FREE FURFURAL BOTTOMS OF THE EXTRACT STRIPPING ZONE IN THE EXTRACTIVE DISTILLATION ZONE.