Aromatic oils by thermal polymerization of refinery streams

A heat soaked polymer by-product from the production of gasoline using the 90 DEG -400 DEG F. steam cracker naphtha as feed is upgraded by first subjecting the same to a thermal polymerization and then subjecting the thermal polymerization product to a hydrotreating or hydrogenation step or both. Generally, the hydrotreatment is accomplished at relatively mild conditions so as to avoid any change in aromatic ring structure. Hydrogenation, on the other hand, is accomplished at more severe conditions so as to effect hydrogenation of the aromatic rings. In those cases where a mild hydrotreatment only is used, the products obtained are, generally, useful as aromatic oils of light color. Where more severe hydrogenation is used, on the other hand, the products are useful as naphthenic oils.