Physicochemical Properties of Room-Temperature Molten Salts of Symmetrical Tetraalkyl Ammonium Diisooctylsulfosuccinates

Water-immiscible room-temperature molten salts (RTMSs) have drawn much attention as possible alternatives of conventional organic solvents in the field of two-phase organic synthesis and liquid-liquid extraction. To make RTMSs immiscibile with water, hydrophobic anions, especially PF6 and bis(persluoro alkylsulfonyl) imide have been employed. In the present study, we propose a RTMS composed of diisooctyl sulfosuccinate(DOSS), which is hydrophobic anion without fluoroatoms. We examine the miscibility of this new type of RTMS with water and the electrochemical properties of the RTMS | water interface. RTMS was prepared as follows. Equimolar quantities of symmetrical quaternary ammonium, R4NX( R= C4, C5, C6, C7, C8; X= Br, I) and Aerosol-OT(Na DOSS) were dissolved into chloroform and washed several times with water. After evaporation, we obtained yellow viscous oil. In order to remove the extra hydrophobic halide as a participate, crude RTMS was dissolved into methanol, then added Ag2O. After further purification with methanol and water, the RTMS was dried under vacuum. We obtained the viscous clear colorless liquid. Density, conductivity, mutual miscibility with water has been measured for obtained RTMSs. Cyclic voltammograms of the R4NDOSS | water interface were measured. The electrochemical cell used was, Ag/AgCl | W2 | RTMS | W1 | AgCl/Ag