Low-melting, low-viscous, hydrophobic ionic liquids: aliphatic quaternary ammonium salts with perfluoroalkyltrifluoroborates.
A novel class of low-melting, hydrophobic ionic liquids based on relatively small aliphatic quaternary ammonium cations ([R(1)R(2)R(3)NR](+), wherein R(1), R(2), R(3) = CH(3) or C(2)H(5), R = n-C(3)H(7), n-C(4)H(9), CH(2)CH(2)OCH(3)) and perfluoroalkyltrifluoroborate anions ([R(F)BF(3)](-), R(F) = CF(3), C(2)F(5), n-C(3)F(7), n-C(4)F(9)) have been prepared and characterized. The important physicochemical and electrochemical properties of these salts, including melting point, glass transition, viscosity, density, ionic conductivity, thermal and electrochemical stability, have been determined and comparatively studied with those based on the corresponding [BF(4)](-) and [(CF(3)SO(2))(2)N](-) salts. The influence of the structure variation in the quaternary ammonium cation and perfluoroalkyltrifluoroborate ([R(F)BF(3)](-)) anion on the above physicochemical properties is discussed. Most of these salts are liquids at 25 degrees C and exhibit low viscosities (58-210 cP at 25 degrees C) and moderate conductivities (1.1-3.8 mS cm(-1)). The electrochemical windows of these salts are much larger than those of the corresponding 1,3-dialkyimidazolium salts. Additionally, a number of [R(F)BF(3)](-) salts exhibit plastic crystal behavior.
Zhou
Zhi-Bin
ZB
Research Institute for Ubiquitous Energy Devices, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
Matsumoto
Hajime
H
Tatsumi
Kuniaki
K
D001881:Borates / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004553:Electric Conductivity; D004563:Electrochemistry; D005466:Fluorocarbons / Q000737:chemistry*; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013818:Thermogravimetry; D014783:Viscosity
D001881:Borates; D005466:Fluorocarbons; D007202:Indicators and Reagents; D000644:Quaternary Ammonium Compounds