CLAIMS
1. A process for the isomerization of a feed of hydrocarbon compounds comprising C5
and/or Q hydrocarbon compounds, said process comprising a loop for recycling at least one chlorinated compound, and in which process:
a) an isomerization unit (1) is supplied with at least one liquid fraction of said feed of hydrocarbon compounds and the isomerization is carried out in the presence of a chlorinated catalyst;
b) a stabilization unit (20) comprising at least one stabilization column (2) is supplied with the effluent obtained from the isomerization unit (1) and a separation is carried out in said stabilization unit (20) into:
• a gaseous effluent comprising at least one chlorinated compound;
® a liquid effluent comprising a concentration CA of C$+ compounds; and
• a liquid flow comprising at least one isomerate of the feed of hydrocarbon
compounds;
c) the following is carried out in an absorption unit (7) comprising at least one absorption
column (3):
• a first contact between the gaseous effluent obtained from step b) and a washing fluid, said washing fluid being selected from a complementary liquid fraction of said feed of hydrocarbon compounds and/or at least a portion of said liquid flow comprising at least one isomerate of the feed of hydrocarbon compounds obtained from step b); said washing fluid comprising a concentration CB of CS+ compounds, with CA < CB;
• a second contact between the gaseous flow resulting from said first contact and said liquid effluent obtained from step b);
d) a liquid flow enriched in chlorinated compounds is extracted from the absorption unit
(7) and returned to the isomerization unit (1);

e) said liquid flow comprising at least one isomerate of the feed of hydrocarbon compounds is extracted from the stabilization unit (20).
2. The process according to claim 1, characterized in that the liquid flow comprising at least one isomerate of the feed of hydrocarbon compounds of step e) undergoes a separation in a separation unit (4) in order to obtain at least one flow with a higher octane number than said liquid flow of step e) and at least one flow with a lower octane number than said liquid flow of step e).
3. The process according to claim 2, characterized in that at least a portion of the flow with a lower octane number than said liquid flow of step e) is recycled to the absorption unit (7) as washing fluid,
4. The process according to claim 2 or claim 3, characterized in that at least a portion of the flow with a lower octane number than said liquid flow of step e) is recycled upstream of the isomerization unit (1). said recycled flow being mixed with the feed of hydrocarbon compounds.
5. The process according to any one of claims 3 to 4, characterized in that the absorption unit (7) comprises an absorption column (3), and said absorption column (3) is supplied during step c):

• with said washing fluid;
• with gaseous effluent obtained from step b), said gaseous effluent being supplied to the absorption column (3) below the supply for said washing fluid;
• with liquid effluent obtained from step b), said liquid effluent being supplied to the head of the absorption column (3) above said washing fluid.
6. The process according to any one of claims 1 to 4, characterized in that the absorption
unit (7) comprises two absorption columns (3, 30), and in that during step c), the washing
fluid and the gaseous effluent obtained from step b) are supplied to the first absorption
column (3), and in that the gaseous flow resulting from the first contact between the

gaseous effluent obtained from step b) and said washing fluid and the liquid effluent obtained from step b) are supplied to the second absorption column (30).
7. The process according to any one of claims 1 to 6, characterized in that said feed of hydrocarbon compounds, optionally as a mixture with said liquid flow comprising at least one isomerate of the feed of hydrocarbon compounds obtained from step b), is dried upstream of the isomerization unit (1) and the absorption unit (7).
8. The process according to any one of claims 1 to 7, characterized in that the washing fluid is cooled upstream of the absorption unit (7).
9. The process according to any one of claims 1 to 8, characterized in that when the washing fluid is a complementary liquid fraction of said feed, the flow rate of said complementary liquid fraction of said feed is preferably in the range 5% to 50% by volume of the total flow of said feed.
10. The process according to any one of claims 1 to 9, characterized in that the concentration of C4- compounds comprised in the liquid effluent obtained in step b) is more than 15% by weight.
11. The process according to any one of claims 1 to 10, characterized in that the gaseous flow obtained from the second contact in the absorption unit (7) is extracted and treated in a unit for the treatment of gaseous effluents.
12. The process according to any one of claims 1 to II3 characterized in that a portion of the liquid effluent obtained from step b) is sent directly to a unit for the treatment of gaseous effluents after vaporization.
13. The process according to any one of claims 1 to 12, characterized in that step a) is carried out at a temperature in the range 100°C to 300°C, at a pressure in the range 0.2 to 3.5 MPa, with a hydrogen/hydrocarbons molar ratio in the range 0.1:1 to 1:1 and with a space velocity in the range 0.5 to 10 h"1.

14. The process according to any one of claims 1 to 13, characterized in that step a) is carried out in the presence of a chlorinated catalyst comprising an alumina support and a metal from group VIII.
15. The process according to claim 14, characterized in that the catalyst comprises 2% to 10% by weight of chlorine with respect to the total catalyst weight, and 0.1% to 0.40% by weight of platinum with respect to the total catalyst weight.