Butene and butadiene purification by plural stage distillation

Claim 1

A PROCESS COMPRISING THE STEPS OF PASSING A FEED STOCK COMPRISING FURFURAL, BUTADIENE AND CIS AND TRAND BUTENES-2 SUBSTANTIALLY FREE OF BUTENES-1 INTO A HYDROCARBON STRIPPING ZONE AND THEREIN STRIPPING SAID BUTADIENE AND CIS AND TRANS BUTENES-2 FROM THE FURFURAL, DISTILLING THE STRIPPED MATERIAL THEREBY PRODUCING AN OVERHEAD PRODUCT COMPRISING BUTADIENE CONTAINING MINOR PROPORTION OF SAID BUTENES-2 AND A BOTTOM PRODUCT CONSISTING ESSENTIALLY OF BUTENES-2, FURTHER DISTILLING SAID OVERHEAD PRODUCT THEREBY PRODUCING AN OVERHEAD PRODUCT OF SUBSTANTIALLY PURE BUTADIENE AND A BOTTOMS PRODUCT OF BUTADIENE CONTAINING MINOR PROPORTIONS OF SAID BUTENES-2, AND RETURNING THIS BOTTOMS PRODUCT TO THE FIRST MENTIONED DISTILLING STEP AS REFLUX AND WITHDRAWING BOTTOMS FROM THIS FIRST MENTIONED DISTILLING STEP AND SAID OVERHEAD PRODUCT OF SUBSTANTIALLY PURE BUTADIENE AS PRODUCTS OF THE OPERATION.