Combination process for producing piperazine and nu-aminoethylpiperazine

Claim 1

IN A METHOD WHICH COMPRISES THE STEPS OF BRINGING A MONOETHANOLAMINE INTO CONTACT WITH A HYDROGENATION CATALYST IN A PRIMARY REACTION ZONE IN THE PRESENCE OF HYDROGEN AND FROM ABOUT TWO TO ABOUT TEN MOLS OF AMMONIA PER MOL OF AMINE FEEDSTOCK UNDER CONDITIONS OF TEMPERATURE AND PRESSURE SUFFICIENT TO CYCLIZE AT LEAST A PORTION OF SAID FEEDSTOCK TO FORM PIPERAZINE, WHEREBY A REACTION PRODUCT IS FORMED COMPRISING AN AMINE MIXTURE, THE IMPROVEMENT WHICH COMPRISES: (A) SEPARATING SAID REACTION PRODUCT IN A FIRST SEPARATION ZONE INTO AT LEAST A PIPERAZINE PRODUCT FRACTION AND A SECOND SUBSTANTIALLY PIPERAZINE-FREE DISTILLATE FEEDSTOCK FRACTION BOILING WITHIN THE RANGE OF ABOUT 180* TO ABOUT 250*C. AND COMPRISING NAMINOETHYLPIPERAZINE, (B) SEPARATELY BRINGING SAID SECOND FEEDSTOCK INTO CONTACT WITH A HYDROGENATION CATALYST IN A SECOND REACTION ZONE UNDER CONVERSION CONDITIONS LESS SEVERE THAN THOSE EMPLOYED IN SAID PRIMARY REACTION ZONE TO CONVERT THE SECOND FEEDSTOCK INTO A SECOND REACTION PRODUCT COMPRISING PIPERZINE AND N-AMINOETHYLPIPERAZINE, (C) SEPARATING SAID SECOND REACTION PRODUCT IN A SECOND SEPARATION ZONE INTO A CRUDE PIPERAZINE FRACTION AND A PRODUCT N-AMINOETHYPIPERAZINE DISTILLATE FRACTION BOILING WITHIN THE RANGE OF ABOUT 180* TO ABOUT 250*C. CONSISTING ESSENTIALLY OF N-AMINOETHYLPIPERAZINE, (D) RECYCLING SAID CRUDE PIPERAZINE FRACTION TO SAID FIRST SEPARATION ZONE, AND (E) RECOVERING SAID PRODUCT N-AMINOETHYLPIPERAZINE DISTILLATE FRACTION, (F) SAID CONVERSION CONDITIONS IN SAID PRIMARY REACTION ZONE INCLUDING A TEMPERATURE WITHIN THE RANGE OF ABOUT 200* TO ABOUT 300*C., A PRESSURE WITHIN THE RANGE OF ABOUT 65 TO ABOUT 225 ATMOSPHERES, INCLUDING A HYDROGEN PARTIAL PRESSURE OF AT LEAST TEN ATOMOSPHERES AND A CONTACT TIME CORRESPONDING TO A FEED RATE OF ABOUT 0.4 TO ABOUT 0.8 POUND OF SAID AMINE FEEDSTOCK PER HOUR POUND OF HYDROGENATION CATALYST, (G) SAID LESS SEVERE CONVERSION CONDITIONS IN SAID SECOND REACTION ZONE INCLUDING A TEMPERATURE WITHIN THE RANGE OF FROM ABOUT 180* TO ABOUT 220*C. AND A CONTACT TIME CORRESPONDING TO A FEED RATE OF ABOUT 0.8 TO ABOUT 1.6 POUNDS OF SAID SECOND FEEDSTOCK PER HOUR PER POUND OF CATALYST, (H) SAID HYDROGENATION CATALYST CONSISTING OF COPPER, NICKEL AND CHROMIUM OXIDE HAVING THE COMPOSITION, CALCULATED IN MOL PERCENT ON AN OXIDE-FREE BASIS, OF 60% TO 85% NICKEL, 14% TO 37% COPPER AND 1% TO 5% CHROMIUM.