Separation of light hydrocarbons with ionic liquids: A review

Light hydrocarbons (C-1-C-4) are fundamental raw materials in the petroleum and chemical industry. Separation and purification of structurally similar paraffin/olefin/alkyne mixtures are important for the production of high-purity or even polymer-grade light hydrocarbons. However, traditional methods such as cryogenic distillation and solvent absorption are energy-intensive and environmentally unfriendly processes. Ionic liquids (ILs) as a new alternative to organic solvents have been proposed as promising green media for light hydrocarbon separation due to their unique tunable structures and physicochemical properties resulting from the variations of the cations and anions such as low volatility, high thermal stability, large liquidus range, good miscibility with light hydrocarbons, excellent molecular recognition ability and adjustable hydrophylicity/hydrophobicity. In this review, the recent progresses on the light hydrocarbon separation using ILs are summarized, and some parameters of ILs that influence the separation performance are discussed. (C) 2019 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.