Alkylation of aromatic hydrocarbons

Claim 1

A COMBINATION PROCESS WHICH COMPRISES ABSORBING IN AN ABSORPTION ZONE A NORMALLY GASEOUS OLEFIN HYDROCARBON FROM A GAS STREAM IN A POLYALKYLAROMATIC HYDROCARBON AT A PRESSURE OF FROM ABOUT 100 TO ABOUT 2000 POUNDS PER SQUARE INCH, SAID POLYALKYLAROMATIC HYDROCARBON BEING CHARACTERIZED BY HAVING A HIGHER BOILING RANGE THAN THE DESIRED ALKYLATED AROMATIC HYDROCARBON PRODUCT OF THE PROCESS, PASSING TO A STRIPPING ZONE SAID ABSORBED OLEFIN HYDROCARBON AND SAID POLYALKYLAROMATIC HYDROCARBON, REMOVING FROM THE PROCESS AS BOTTOMS FROM SAID STRIPPING ZONE AT LEAST A PORTION OF SAID POLYALKYLAROMATIC HYDROCARBON, PASSING TO AN ALKYLATION ZONE AS AN OVERHEAD FROM SAID STRIPPING ZONE SAID OLEFIN HYDROCARBON IN ADMIXTURE WITH A MOLAR EXCESS BASED ON SAID NORMALLY GASEOUS OLEFIN HYDROCARBON OF AROMATIC HYDROCARBON TO BE ALKYLATED, ALKYLATING IN THE ALKYLATION ZONE SAID AROMATIC HYDROCARBON WITH SAID OLEFIN HYDROCARBON IN THE PRESENCE OF AN ACID-ACTING ALKYLATION CATALYST AT ALKYLATION-ALKYL TRANSFER CONDITIONS, SEPARATING FROM EFFLUENTS OF SAID ALKYLATION ZONE UNREACTED AROMATIC HYDROCARBON, DESIRED ALKYLATED AROMATRIC HYDROCARBON PRODUCT AND HIGHER BOILING POLYALKYLAROMATIC HYDROCARBON FOR RECYCLING THE UNREACTED AROMATIC HYDROCARBON FOR REUSE IN THE PROCESS, RECOVERING ALKYLATED AROMATIC HYDROCARBON AS PRODUCT FROM THE PROCESS, AND RECYCLING SAID HIGHER BOILING POLYALKYLAROMATIC HYDROCARBON TO THE ABSORPTION ZONE AS ABSORBENT FOR SAID NORMALLY GASEOUS OLEFIN HYDROCARBON.