Ionic Liquids as Sustainable Extractants in Petrochemicals Processing pp. 35-78
Authors: (G. Wytze Meindersma, Antje R. Hansmeier, Ferdy (S.A.F.) Onink, André B. de Haan, Eindhoven University of Technology, The Netherlands)
Abstract: Only a few ionic liquids can be successfully applied for the separation of aromatic hydrocarbons from mixtures of aromatic and aliphatic hydrocarbons. Ionic liquids have been identified as promising solvents to replace conventional solvents in liquid-liquid
extraction of aromatic hydrocarbons requiring less process steps and less energy consumption, provided that the mass-based aromatic distribution coefficient and/or the aromatic/aliphatic selectivity are higher than those of the current state-of-the-art solvents such as sulfolane. The most suitable ionic liquids from our evaluation are [3-mebupy]B(CN)4, [3-mebupy]C(CN)3, [3-mebupy]N(CN)2 and [bmim]C(CN)3. The aromatic distribution coefficients of these ILs are a factor of 1.2 to 2.5 higher and the aromatic/aliphatic selectivities are up to a factor of 1.9 higher than with sulfolane.
A process evaluation of the extraction of aromatic hydrocarbons with ionic liquids shows that a high aromatic distribution coefficient with a reasonable aromatic/aliphatic selectivity could reduce the investment costs of the aromatic/aliphatic separation by a factor of two compared to a conventional separation with e.g. sulfolane.