Reactivity of Ionic Liquids: Studies on Thermal Decomposition Behavior of 1-Butyl-3-methylimidazolium Tetrafluoroborate
Reactivity of Ionic Liquids: Studies on Thermal Decomposition Behavior of 1-Butyl-3-methylimidazolium Tetrafluoroborate
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DOI：
10.1016/j.tca.2020.178786
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发表时间：
2020-12-01
影响因子：
3.5
通讯作者：
Schmidt, Peer
中科院分区：
文献类型：
--
作者：
Knorr, Monika;Icker, Maik;Schmidt, Peer
离子液体1-丁基-3-甲基咪唑四氟硼酸盐[C(4)C(1)im]BF4是无机材料合成和分析中常用的溶剂。然而，它的应用经常与试错法联系在一起。因此，详细的热行为知识是理解[C(4)C(1)im]BF4反应性的关键信息。1-丁基-3-甲基咪唑四氟硼酸盐在冷中表现为玻璃，其玻璃化转变温度为theta(G)=-83℃。在10K.min(-1)[C(4)C(1)im]BF4的加热过程中，表现为稳定在350℃以上，起始温度theta(起始，DSC)=375℃，theta(起始)，(DTG)=422℃，(theta起始)，(Tg)=437℃。因此，在一步反应中发生热分解形成1-甲基-1H-咪唑(CH3C3H3N2或C4H6N2)，采用热重-质谱法和傅里叶变换红外光谱联用技术测定了丁二烯(C4H8)、含氟甲烷(CH3F)和三氟化硼(BF3)的主要形态。为了更具体地描述其热行为，本文在最高工作温度-MOT动力学模型的基础上对其随温度和时间变化的稳定性进行了评估。显然，热稳定性随着应用时间的延长而提高，因此一小时的热稳定性为193摄氏度，而一天的热稳定性仅达到141摄氏度，一周的热稳定性仅达到114摄氏度。初期的分解(
The Ionic Liquid 1-butyl-3-methylimidazolium tetrafluoroborate [C(4)C(1)im]BF4 serves as a commonly solvent in inorganic material synthesis and analytics. Nevertheless, its application is frequently associated with trial and error approaches. Thereupon, detailed knowledge on the thermal behavior is the key information for understanding the reactivity of [C(4)C(1)im]BF4. 1-butyl-3-methylimidazolium tetrafluoroborate behaves as a glass in the cold, its glass transition temperature being theta(g) = -83 degrees C. During heating with 10 K.min(-1) [C(4)C(1)im]BF4 appears to be stable above 350 degrees C with onset temperatures theta(onset, DSC )= 375 degrees C, theta(onset), (DTG )= 422 degrees C, and (theta onset), (TG) = 437 degrees C. Thereby, thermal decomposition occurs in a single step reaction forming 1-methyl-1H-imidazole (CH3C3H3N2 or C4H6N2), but-l-ene (C4H8), fluoromethane (CH3F) and boron trifluoride (BF3) as main species, as determined by thermogravimetry coupled with mass spectrometry and FTIR spectroscopy. To be more specific in thermal behavior, the temperature and time dependent stability is evaluated here on the basis of the kinetic model of maximum operation temperature - MOT. Clearly, thermal stability rises with application time, thus being 193 degrees C for one hour, while reaching only 141 degrees C for one day, and 114 degrees C for one week. The incipient decomposition (