Hydrocarbon isomerization process

An isomerization process which comprises:

• contacting in a reaction zone, in the presence of hydrogen, a hydrocarbon feed comprising a saturated aliphatic hydrocarbon, a hydrogen halide selected from the group consisting of hydrogen chloride, hydrogen bromide and mixtures thereof, said hydrocarbon feed and hydrogen halide being substantially in liquid phase, and a metal halide catalyst selected from the group consisting of aluminum chloride, aluminum bromide and mixtures thereof, at a temperature ranging from at least about 50.degree.C. to the critical temperature of the mixture of said hydrocarbon feed and said hydrogen halide, said critical temperature ranging up to about 150.degree.C., the partial pressure of said hydrogen ranging from about 40 to about 1000 psia, the molar ratio of said hydrogen to said hydrocarbon feed ranging from 0.05 to 2.5 moles hydrogen per mole hydrocarbon feed, the partial pressure of the mixture of said hydrocarbon feed and said hydrogen halide being maintained at least equal to the critical pressure of the hydrocarbon feed and not greater than the critical pressure of said mixture of hydrocarbon feed and hydrogen halide, said partial pressure of the mixture of said hydrocarbon feed and said hydrogen halide ranging from about 250 to about 2500 psia, and wherein the molar ratio of said hydrogen halide to said hydrocarbon feed is at least 1:1 and the molar ratio of said hydrogen halide to said metal halide catalyst ranges from about 10:1 to about 40:1.