The invention provides a high
octane number
gasoline pool comprises at least 2% of di-branched paraffins containing 7 carbon atoms, and a process for producing this
gasoline pool by hydro-isomerizing a feed constituted by a C5 to C8
cut which comprises at least one hydro-
isomerization section and at least one separation section, in which the hydro-
isomerization section and at least one separation section, in which the hydro-
isomerization section comprises at least one reactor. The separation section comprises at least one unit and produces at least two streams: a first
stream which is rich in di- and tri-branched paraffins, and possibly in naphthenes and aromatic compounds which is sent to the
gasoline pool; and in a first version of the process, a second
stream is produced which is rich in straight-chain and mono-branched paraffins which is recycled to the inlet of the hydro-isomerization section, while in a second version of the process, a second flux is produced which is rich in straight-chain paraffins which is recycled to the inlet of a first hydro-isomerization section and a third
stream is produced which is rich in mono-branched paraffins which is recycled to the inlet of a second hydroisomerization section.