Efficient separation of phenols from oils via forming deep eutectic solvents

Abstract

Ammonium salts have been used to efficiently separate phenols from oils (where hexane, toluene and p-xylene were used as model oils) by forming a deep eutectic solvent, which is a nonaqueous process and avoids the use of mineral alkalis and acids that produces phenol containing waste water.

The new liquid–liquid extraction method for separation of phenolic compounds from coal tar

“…DES has recently been found to be an efficient separation medium, which is cheaper than ionic liquids. Pang et al [26] found that choline chloride can react with phenols to form DES, which become a uniform liquid phase to separate phenols from oil. Guo et al [27,28] studied the phenol removal efficiency of choline chloride and its homologous compounds from model oils and then discussed how different cations and anions affect the removal efficiency of phenol.…”

Separation of toluene from toluene/alkane mixtures with phosphonium salt based deep eutectic solvents

“…Some other DESs based on ChCl were formed with malonic acid at 0°C, phenol at − 40°C, and glycerol at − 35°C [5]. ChCl could form DES with different phenols [10] and could be used to separate phenols from oil with high efficiencies [11,12]. Recently DESs based on phosphonium-based salts have attracted much attention.…”

Efficient separation of phenol from oil by acid–base complexing adsorption

“…Thus, the alternative methods have already been studied for a long time [8]. Chlorinated organic salts, e.g., choline chloride (ChCl), triethylammonium hydrochloride (Et 3 NHCl) [9], tetraethylammonium chloride [10], and 1-butyl-3-methylimidazolium chloride [11,12], can separate phenolic compounds from model oils with good efficiency. This method uses the H-bonding between -OH group and Cl -.…”