Phenolic compounds, which are basic materials of the organic chemical industry,are mainly products derived from direct coal liquefaction or coal tar. The presentmethod to separate phenol compounds from oil mixtures is to chemically extractphenols using aqueous alkaline solutions (such as aqueous NaOH) and then to acidifythe extract by mineral acids (such as aqueous H_2SO_4) to recover the phenols. Howeverthere are disadvantages: the use of large amounts of both strong alkalis and acids andthe production of excessive amounts of waste water containing phenols.In this work, ammonium salts was found to be successful as eutectic media forseparating phenols from direct coal liquefaction oil and coal tar. First, ammoniumsalts have been used to efficiently separate phenols from modeling oils (hexane,toluene and p-xylene as model oil) via forming eutectic solvents. Ammonium salts,especially choline chloride (ChCl), were found to be successful as eutectic media forseparating phenols (phenol and cresols) from oils (hexane, toluene and p-xylene).ChCl shows a short eutectic equilibrium time less than 3 min (see Figure 1) and anin-sensitivity to eutectic temperature. Significantly, no ChCl was found in the upperoil phase at equilibrium with the eutectic solvent. ChCl in the eutectic solvent can berecovered by diethyl ether and reused without mass loss and reduction in separationefficiency.Then, ChCl were used to separate phenolic compounds in coal tar and coalliquefaction oil via forming eutectic solvents (see Figure 2). ChCl also shows a shorteutectic equilibrium time for coal tar and coal liquefaction oil. The extractionefficiencies of phenols from coal tar (distillate at 130-260 °C) with a total phenol
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