Process for recovery and purification of

Claim 1

IN RECOVERING C5 AND C4 CYCLODIENES FROM CARCKED PERTOLEUM NAPHTHA, THE STEPS WHICH COMPRISE DISTILLING FROM THE NAPHTHA A X4 TO C5 HYDROCARBONS CUT AT TEMPERATURES BELOW 175* F., REMOVING C4 HYDROCARBONS FROM THE C4 TO C9 CUT AT TEMPERATURE BELOW 160* F. TO OBTAIN A REMAINING C5 TO C9 HYDROCARBON FRACTION, SOAKING SAID C5 TO C9 HYDROCARBON FRACTION AT TEMPERATURES OF ABOUT 150* F. TO 240* F. UNTIL THE CYLODIENES IN SAID FRACTION ARE DIMERIZED, FRACTIONALLY DISTILLING C5 TO C9 COMPONENTS FROM THE RESULTING SOAKED FRACTION TO OBTAIN THE CYCLODIENE DIMERS AS A CONCENTRATE SUBSTANTIALLY FREE OF C6 AND LOWER-BOILING HYDROCARBONS , PASSING A HIGH BOILING RESIDUAL PORTION OF SAID INITIAL CRACKED NAPHTHA CONTAINING C5 TO C12 HYDROCARBONS INTO A HIGH TEMPERATURE STRIPPING ZONE, STRIPPING SAID RESIDUAL NAPHTHA FRACTION OF ADDITIONAL C5 TO C9 HYDROCARBONS AT TEMPERATURES BETWEEN 240* F. AND 410* F., SOAKING SAID ADDITIONAL C5 TO C9 HYDROCARBONS AT ABOUT 150* F. TO 240* F. TO OBTAIN MOSE OF THE CYCLODIENE DIMERS, PASSING THE CYCLODIENE DIMERS INTO A DEPOLYMERIZATION ZONE IN WHICH THE CYCLODIENE DIMERS INTO A DEPOLYMERIZATION AT TEMPERATURES RANGING FROM ABOVE 350* FF. TO ABOUT 450* F., RAPIDLY REMOVING THE RESULTING CYCLODIENE MONOMER CAPORS WITH HIGHER BOILING C7-C9 HYDROCARBONS PRESENT IN SAID CONCENTRATES TO A FRACTIONATION ZONE, AND FRACTIONALLY SEPARATING THE CYCLODIENE MONOMERS.