Simultaneous isomerization of pentane and hexane with selective fractionation

Claim 1

A PROCESS FOR ISOMERIZING AN ISOMERIZABLE HYDROCARBON CHARGE CONTAINING HYDROCARBONS HAVING FROM ABOUT FIBE TO ABOUT SIX CARBON ATOMS PER MOLECULE, WHICH PROCESS COMPRISES COMBINING SAID CHARGE WITH A PENTANERICH ISOMERIZED PRODUCT, REMOVING ISOPENTANE FROM THE RESULTING MIXTURE AND PASSING THE DEISOPENTANIZED PORTION OF SAID MIXTURE WITH HYDROGEN INTO A REACTION ZONE CONTAINING AN ISOMERIZATION CATALYTIC COMPOSITE OF A REFRACTORY INORGANIC OXIDE AND A PLATINUM-GROUP METAL, AND MAINTAINED UNDER ISOMERIZATION CONDITIONS, SEPARATING THE RESULTING REACTION ZONE EFFLUENT TO PROVIDE A HYDROGENRICH GASEOUS PHASE AND A LIQUID PHASE CONTAINING ISOPENTANE AND ISOHEXANE, SEPARATING SAID LIQUID PHASE INTO A FIRST HYDROCARBON FRACTION CONTAINING PENTANES AND A SECOND HYDROCARBON FRACTION CONTAINING HEXANES, RECYCLING SAID PENTANE-CONTAINING FRACTION TO COMBINE WITH SAID HYDROCARBON CHARGE PRIOR TO THE REMOVAL OF ISOPENTANE THEREFROM, REMOVING A PORTION OF SAID SECOND FRACTION FROM SAID PROCESS FRACTIONATING THE REMAINDER OF SAID SECOND FRACTION TO SEPARATE ISOHEXANES THEREFROM, AND COMBINING THE DEISOHEXANIZED PORTION OF SAID SECOND FRACTION CONTAINING NORMAL HEXANE WITH THE AFORESAID DEISOPENTANIZED CHARGBE AND HYDROGEN LPRIOR TO REACTING THE SAME IN SAID REACTION ZONE.