Process for recovery of cyclopentadiene

Claim 1

A CONTINUOUS PROCESS FOR FORMING AND SEPARATING A MONOMERIC CYCLOALKADIENE FORM A CRACKED PETROLEUM NAPHTHA FRACTION CONTAINING THE CYCLOALKADIENE DIMER, SAID NAOHTHA FRACTION HAVING BEEN TOPPED TO REMOVE MMOMOMERIC DIOLEFINS AND C7 AND LOWER HYDROCARBONS THAT BOIL BELOW 350* G., WHICH COMPRISES PASSING SAID TOPPED FRACTION CONTAINING SUBSTANTIALLY THE SAME AMOUNT OF THE CYCLOALKADIENE DIMER AS WAS PRESENT IN THE NAPHTHA FRACTION PRIOR TO THE TOP PING TO THE FIRST OF A SERIES OF TWO HEATING ZONES WHERE THIS DIMER UNDERGOES DEPOLYMERIZATION, THE FIRST ZONES BEING COMMUNICATION WITH A SECAND HEATING ZONE SO AS TO SUPPLY A RESIDUAL LIQUID PORTION OF THE TOPPED NAPTHA FRACTION CONTINUOUSLY THERETO; HEATING SAID RESIDUAL LIQUID PORTION FROM THE FIRST HEATING ZONE IN THE LIQUID PHASE IN THE SECOND HEATING ZONE TO DEPOLYMERIZE THE CYCLOALKADIENE DIMER WHICH SAID RESIDUAL LIQUID PORTIONS CONTAINS AND TO FORM VAPOR OF ITS MOMOMER; SWEEPING HOT VAPOR CONTAINING THE MONOMER VAPOR FROM SAID SECOND HEATING ZONE TO SAID FIRST HEATING ZONE STRIP ADDITIONAL CYCLOALKADIENE MONOMER THEREFROM, RAKING OFF THE COMBINED VAPOR FROM SAID FIRST ZONE TO A FRACTIONATION ZONE SEPARATE FROM ANY ZONE IN WHICH INITIAL NAPTHA FRACTION IS TOPPED; FRACTIONATING THE CYCLOALKADIENE MONOMEER FROM THE VAPORS ENTERING SAID FRACTIONATION ZINE IN THE ABSENCE OF C7 AND LOWER HYDROCARBONS OTHER THAN CYCLOALKADIENE MONOMER TO OBTAIN A DISTILLATE PRODUCT OF THE MONOMER, AND RETURNING A BOTTOMS PORTION FROM SAID FRACTIONATION ZONE TO SAID FIRST HEATING ZONE FOR FURTHER RECOVERY OF MONOMERIC CYCLOALKADIENE.