Process for hydroisomerization of paraffins

Claim 1

IN A PROCESS COMPRISING CONTACTING IN A HYDROISOMERIZATION ZONE UNDER HYDROISOMERIZATION CONDITIONS A SUPPORTED PLATINUM-TYPE HYDROISOMERIZATION CATALYST, A HYDROCARBON COMPRISING AN ALIPHATIC PARAFFIN CONTAINING NOT MORE THAN 7 CARBON ATOMS PER MOLECULE, HYDROGEN, AND A HALOGEN MATERIAL VOLATILE UNDER HYDROISOMERIZATION CONDITIONS SELECTED FROM THE GROUP CONSISTING OF FREE HALOGEN, HYDROGEN HALIDE AND ALKYL HALIDE, AND RECOVERING A REACTION EFFLUENT WHICH CAN BE FRACTIONATED INTO A STABILIZED LIQUID FRACTION SUBSTANTIALLY ALL OF WHOSE HYDROCARBONS CONTAIN MORE THAN 4 CARBON ATOMS PER MOLECULE WHICH ALSO CONTAINS HALOGEN AND INTO ANOTHER FRACTION LIGHTER THAN SAID STABILIZED LIQUID, THE IMPROVEMENT WHICH COMPRISES FRACTIONATING SAID REACTION EFFLUENT TO SEPARATE THE STABILIZED LIQUID SUBSTANTIALLY ALL OF WHOSE HYDROCARBONS CONTAIN MORE THAN 4 CARBON ATOMS PER MOLECULE WHICH ALSO CONTAINS HALOGEN FROM THE FRACTION LIGHTER THAN SAID STABILIZED LIQUID, MEASURING THE HALOGEN CONCENTRATION IN SAID STABILIZED LIQUID FRACTION, A FIRST CONCENTRATION RANGE OF HALOGEN IN SAID STABILIZED LIQUID FRACTION CORRESPONDING TO BOTH HIGH ACTIVITY OF SAID CATALYST AND A LOW RATE OF DEACTIVATION OF SAID CATALYST, AN INCREASE IN CONCENTRATION OF HALOGEN IN SAID STABILIZED LIQUID FRACTION FROM SAID FIRST RANGE TO A SECOND CONCENTRATION HIGHER THAN SAID FIRST CONCENTRATION RANGE INDICATING RAPID CATALYST DEACTIVATION, ADJUSTING THE AMOUNT OF SAID HALOGEN MATERIAL CHARGED TO SAID HYDROISOMERIZATION ZONE IN RESPONSE TO A CHANGE IN HALOGEN CONCENTRATION IN SAID STABILIZED LIQUID FRACTION, SAID ADJUSTMENT MAINTAINING THE CONCENTRATION OF HALOGEN IN SAID STABILIZED LIQUID PRODUCT WITHIN SAID FIRST RANGE, AND SAID ADJUSTMENT BEING SUFFICIENTLY PROMPT UPON AN INCREASE IN HALOGEN CONCENTRATION IN SAID STABILIZED LIQUID PRODUCT ABOVE SAID FIRST CONCENTRATION RANGE TO SUBSTANTIALLY AVOID RAPID CATALYST DEACTIVATION.