Thermal stability of imidazolium-based ionic liquids investigated by TG and FTIR techniques
Thermal stability of imidazolium-based ionic liquids investigated by TG and FTIR techniques
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DOI：
10.1007/s10973-016-5267-3
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发表时间：
2016-07-01
影响因子：
4.4
通讯作者：
Yang, Tao
中科院分区：
文献类型：
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作者：
Feng, Wen-quan;Lu, Yi-heng;Yang, Tao
采用等温和非等温热重分析法研究了1-丁基-3-甲基咪唑四氟硼酸盐（[bmim] BF 4）的热稳定性和热分解动力学。结果表明，在180和300 A ℃下存放10 h，[bmim] BF4的转化率分别为1.28和2.57%。当储存在低于300 A ℃时，红外光谱的所有谱带几乎不变。这表明[bmim] BF_4基本上是稳定的。ATR-FTIR光谱表明，在350 A ℃恒温储存2h后，BF（4）（-1）阴离子在1058 cm（-1）附近的相对强度下降了36.7%。由于在300 - 350 A ℃范围内吸收带的强度显著下降，BF（4）（-1）的阴离子可能在空气和热的作用下解离;因此，此时[bmim] BF 4不稳定。用多重扫描法求得的平均热降解表观活化能为105.6kJ mol（-1）。此外，质谱分析还表明，[bmim（+）]的z/m为139.1;在热降解过程中，咪唑鎓阳离子之间存在生成二聚体的可能性。
Thermal stability and thermal decomposition kinetics of 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4) were investigated using isothermal and non-isothermal thermo-gravimetric analysis. The results indicated that isothermal test in the air showed that after storage at 180 and 300 A degrees C both for 10 h, the conversion rate of [bmim]BF4 was 1.28 and 2.57 %, respectively. When stored at less than 300 A degrees C, all bands of IR spectra are nearly unchanged. It suggests that [bmim]BF4 basically is stable. When isothermal stored at 350 A degrees C for 2 h, the ATR-FTIR spectra show that the relative intensity of BF (4) (-1) anion near band of 1058 cm(-1) fell by 36.7 %. Due to the intensity of the absorption band declined significantly in the range of 300-350 A degrees C, the anion of BF (4) (-1) was possibly dissociated by the action of air and heat; thus, at the time [bmim]BF4 is not stable. The average apparent activation energy of thermal degradation obtained by multiple scanning methods is 105.6 kJ mol(-1). Moreover, mass spectrometric analysis also shows that the z/m of [bmim(+)] is 139.1; in the thermal degradation process, the possibility of generating a dimer between imidazolium cation exists.