Ionic structures of nanobased FeCl3/[C4mim]Cl ionic liquids.
We synthesized a series of FeCl(3)/[C(4)mim]Cl (iron(III) chloride with 1-butyl-3-methylimidazolium chloride) ionic liquids. The temperature dependence of the Raman spectra of the FeCl(3)/[C(4)mim]Cl ionic liquids was measured for the first time to analyze their ionic species. In addition, the infrared spectra, thermodynamic properties, and freeze-fracture transmission electron microscopy were combined together with the Raman spectra to reveal the microscopic information of the FeCl(3)/[C(4)mim]Cl ionic liquids. When the mole ratio of FeCl(3)/[C(4)mim]Cl is less than 1, the Raman scattering identifies the presence of [FeCl(4)](-) in the ionic liquid. When FeCl(3) is in excess, [Fe(2)Cl(7)](-) begins to appear. Besides, we found that the relative intensity of the two symmetry vibrations of [Fe(2)Cl(7)](-) is changing as the temperature is varied. The strength of the interionic interactions in FeCl(3)/[C(4)mim]Cl ionic liquids follows the order 1/1.5 > 1.5/1 > 1/1 due to the formation of [FeCl(4)](-) and [Fe(2)Cl(7)](-). The nanostructures in FeCl(3)/[C(4)mim]Cl ionic liquids were observed for the first time by using biological imaging. The sizes of the local domains are found to be tens of nanometers.
State Key Laboratory of Heavy Oil Processing and High Pressure Fluid Phase Behavior & Property Research Laboratory, China University of Petroleum, Beijing 102249, China.
Ji-Guang
JG
Li
Yu-Feng
YF
Hu
Shu-Feng
SF
Sun
Shan
S
Ling
Jin-Zhu
JZ
Zhang
D002712:Chlorides / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties; D013816:Thermodynamics
D002712:Chlorides; D005290:Ferric Compounds; D007093:Imidazoles; D052578:Ionic Liquids; D007477:Ions; C502841:1-butyl-3-methylimidazolium chloride; C024555:ferric chloride