Process of separating c5 diolefins from higher and lower diolefins

Claim 1

THE PROCESS OF SEPARATING A C5 MIXTURE OF ISOPRENE WITH CYCLOPENTADIENE FROM A CRACKED NAPHTHA FRACTION CONTAINING THEM TOGETHER WITH BUTADIENE, METHYL CYCLOPENTADIENE, AND HIGHER-BOILING HYDROCARBONS, WHICH COMPRISES PASSING SAID NAPHTHA FRACTION INTO AN UPPER PART OF A STRIPPING COLUMN WHEREIN C4-C5 HYDROCARBONS PRINCIPALLY RICH IN C4 HYDROCARBONS INCLUDING THE BUTADIENE ARE STRIPPED AND DISTILLED OVERHEAD, REMOVING FROM SAID STRIP PING COLUMN AT A POINT BELOW ITS FEED INLET A VAPOR SIDESTREAM RICH IN C5 HYDROCARBONS INCLUDING THE ISOPRENE AND CYCLOPENTADIENE WITH MINOR AMOUNTS OF C4 AND C5 HYDROCARBONS, PASSING INTO AN INTERMEDIATE PART OF A SECOND FRACTIONATING COLUMN A STREAM OF OVERHEAD VAPORS RICH IN C4 HYDROCARBONS INCLUDING THE BUTADIENE FROM THE FIRST COLUMN AND INJECTING INTO A LOWER PART OF SAID SECOND COLUMN THE VAPOR SIDE-STREAM RICH IN C5 HYDROCARBONS FROM THE FIRST COLUMN, DISTILLING OVERHEAD FROM THE SECOND COLUMN A C4 HYDROCARBON FRACTION AND RECOVERING AS BOTTOMS FROM THE SECOND COLUMN A LIQUID MIXTURE CONTAINING CYCLOPENTADIENE AND ISOPRENE SUBSTANTIALLY FREED OF C4 HYDROCARBONS.