The investment and annual costs for a separation of aromatic hydrocarbons from a naphtha feed (~10 % aromatics) can be 35 to 70 % lower for an extraction with ionic liquids compared to an extraction with sulfolane. Aromatic hydrocarbons (benzene, toluene, ethyl benzene and xylenes) and C4 C10 aliphatic hydrocarbons are normally separated by liquid extraction, extractive distillation or azeotrop...