Process for isomerization of a C7 fraction with co-production of an aromatic molecule-rich fraction

A process for the production of a RON isomerate that is at least equal to 80 and for co-production of an aromatic fraction that for the most part contains toluene, staffing from a C7 fraction containing paraffins, naphthenes and aromatic compounds in any proportion, whereby said process employs at least one step comprising passing fresh feedstock (11) into an extractive distillation unit for extracting aromatic compounds (EA) so as to produce an aromatic fraction (23) containing mostly toluene, and a dearomatized C7 fraction (12) that is introduced into a distillation column (CD) from which are extracted:

• a) A top flow (13) that constitutes an isomerate produced in isomerization unit (IS),
• b) A lateral flow (14) that feeds isomerization unit (IS),
• c) A bottom flow (15), at least in part feeds a unit for opening naphthene rings (OC) from which is extracted an effluent (16) that is sent at least in part to isomerization unit (IS),
• within said isomerization unit (IS), conducting at least one step of isomerization of linear paraffins and mono-branched paraffins into multi-branched paraffins wherein the resultant isomerate contains less than 1% by weight of aromatic compounds, and at least one step of separating resultant stream of linear and mono-branched paraffins from di- and tri-branched paraffins.