Patent ID: 7288687

Claim:
A process for isomerizing xylenes comprising: (a) introducing a feed stream comprising benzene, toluene, and C 5 -C 8 aliphatic hydrocarbons into an extractive distillation zone and separating a bottoms aromatic hydrocarbons stream comprising benzene and toluene, a sidecut aliphatic hydrocarbons stream comprising C 7 -C 8 aliphatic hydrocarbons, and an overhead aliphatic hydrocarbons stream comprising C 5 -C 7 aliphatic hydrocarbons; (b) treating the sidecut aliphatic hydrocarbons stream comprising C 7 -C 8 aliphatic hydrocarbons to generate a substantially solvent free sidecut aliphatic hydrocarbons stream comprising C 7 -C 8 aliphatic hydrocarbons; (c) introducing the substantially solvent free sidecut aliphatic hydrocarbons stream comprising C 7 -C 8 aliphatic hydrocarbons, hydrogen, and a non-equilibrium xylene stream comprising a non-equilibrium mixture of xylenes into an isomerization zone to contact an isomerization catalyst at isomerization conditions and generate an isomerization zone effluent comprising para-xylene.