TY - JOUR
T1 - Physicochemical study of diethylmethylammonium methanesulfonate under anhydrous conditions
AU - Pan, Hailong
AU - Geysens, Pieter
AU - Putzeys, Tristan
AU - Gennaro, Alessia
AU - Yi, Yingting
AU - Li, Hua
AU - Atkin, Rob
AU - Binnemans, Koen
AU - Luo, Jiangshui
AU - Wübbenhorst, Michael
PY - 2020/6/21
Y1 - 2020/6/21
N2 - The protic ionic liquid diethylmethylammonium methanesulfonate ([DEMA][OMs]) was analyzed in depth by differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, and broadband dielectric spectroscopy (BDS) under anhydrous conditions. Karl Fischer titration, NMR, and FT-IR spectra confirmed the high purity of [DEMA][OMs]. The melting point (37.7 °C) and the freezing point (14.0 °C) obtained by DSC agree well with the values determined by BDS (40.0 °C and 14.0 °C). The dc conductivity (σdc) above the melting/freezing point obeys the Vogel-Fulcher-Tammann (VFT) equation well, and thus, the proton conduction in [DEMA][OMs] is assumed to be dominated by the vehicle mechanism. In contrast, the σdc below the melting/freezing point can be fitted by the Arrhenius equation separately, and therefore, the proton conduction is most likely governed by the proton hopping mechanism. The non-negligible influence of previously reported low water content on the physicochemical properties of [DEMA][OMs] is found, indicating the importance of reducing water content as much as possible for the study of "intrinsic" properties of protic ionic liquids.
AB - The protic ionic liquid diethylmethylammonium methanesulfonate ([DEMA][OMs]) was analyzed in depth by differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, and broadband dielectric spectroscopy (BDS) under anhydrous conditions. Karl Fischer titration, NMR, and FT-IR spectra confirmed the high purity of [DEMA][OMs]. The melting point (37.7 °C) and the freezing point (14.0 °C) obtained by DSC agree well with the values determined by BDS (40.0 °C and 14.0 °C). The dc conductivity (σdc) above the melting/freezing point obeys the Vogel-Fulcher-Tammann (VFT) equation well, and thus, the proton conduction in [DEMA][OMs] is assumed to be dominated by the vehicle mechanism. In contrast, the σdc below the melting/freezing point can be fitted by the Arrhenius equation separately, and therefore, the proton conduction is most likely governed by the proton hopping mechanism. The non-negligible influence of previously reported low water content on the physicochemical properties of [DEMA][OMs] is found, indicating the importance of reducing water content as much as possible for the study of "intrinsic" properties of protic ionic liquids.
UR - http://www.scopus.com/inward/record.url?scp=85086925823&partnerID=8YFLogxK
U2 - 10.1063/5.0011756
DO - 10.1063/5.0011756
M3 - Article
C2 - 32571054
AN - SCOPUS:85086925823
VL - 152
JO - The Journal of Chemical Physics
JF - The Journal of Chemical Physics
SN - 0021-9606
IS - 23
M1 - 234504
ER -