Deuteron substitution effects on crystallization in N, N-diethyl-N-methyl-N-
(2-methoxyethyl) ammonium tetrafluoroborate-water mixtures

Hiroshi Abea, Yusuke Imai a, Yukihiro Yoshimura b


aDepartment of Materials Science and Engineering, National Defense Academy, Yokosuka, Kanagawa 239-8686, Japan
 bDepartment of Applied Chemistry, National Defense Academy, Yokosuka, Kanagawa 239-8686, Japan

Chemical Physics Letters 512 (2011) 204-207.

Abstract
We previously reported that amorphization was observed in a room temperature ionic liquid (RTIL)-6.7 mol% H2O mixture by simultaneous X-ray diffraction and differential scanning calorimetry measurements (Y. Imai, H. Abe, T. Goto, Y. Yoshimura, Y. Michishita, H. Matsumoto, Chem. Phys. 352 (2008) 224). Here, the RTIL is N, N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium tetrafluoroborate, [DEME][BF4]. In this study, the phase behavior of the [DEME][BF4]-x mol% (1 - y)H2O  yD2O mixtures is examined systematically by fixing the water concentration at around 7 mol%. Intriguingly, amorphization was completely suppressed and crystallization occurred even when a small amount of D2O was added. The crystallization temperature strongly depends on D substitutions; however, the crystal structure is not influenced by the D2O effect.

Fig. 1
D2O dependence of crystallization temperature, Tc.


Fig. 2
Crystallization temperature, Tc as a function of enthalpy difference in liquid and crystal states, DH.
Fig. 3.
Rocking curves (transverse direction) as a function of D2O concentration at -80 C.
Fig. 4.
X-ray diffraction patterns (radial direction) at -80 C.
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Last Modified: Nov. 1, 2011