應用核磁共振技術定量分析多組分商用電解液及探討乙醯丙酮互變異構化

NMR Quantitative Investigation in systems of the Commercial Lithium Ion Battery Electrolyte and the Tautomerization of Acetylacetone

胡萱黛(HSUAN-TAI HU)

指導教授 ： 賈緒威

中原大學/理學院/化學研究所/碩士(2022年)

https://doi.org/10.6840/cycu202200104

摘要

液態NMR (nuclear magnetic resonance) 能在不破壞樣品的情況下，以微觀角度解析分子的立體結構，更能進一步即時捕捉分子的動態行為。首先，我們必須確認幾種我們建立並使用的定量方法，其誤差在可接受的範圍。接著，我們將有機樣品系統分為化學熱力學與化學動力學兩大方向：前者以混和物組份比例為目標，並以多組份電解液中的有機碳酸酯溶劑為例，除了能夠透過 1D NOE、Diffusion 與一維多核種波譜，配合二維 edited HSQC 與 HMBC 定性出五種碳酸酯溶劑，定量則以鋰鹽的鋰譜做為定性起點，並以鋰鹽與有機碳酸酯溶劑 FEC 得到氟譜積分，最後以氫譜完整定量五種溶劑與鋰鹽組成分的比例；後者則以 Acac 為例，以分子級角度探究大數量的同一化合物中結構的不同分子間轉換與能量的變化，並合理闡述分子間作用力造成的巨觀性質。Acac 互變異構化以 Diffusion 證實有雙酮異構物與烯醇異構物，並確認其分子結構。雙酮異構物與烯醇異構物的能量差異，透過溶劑效應、變溫實驗與氫氘置換實驗結果，推論能使烯醇異構物穩定的存在主要是來自其內的共振能。

關鍵字

定量核磁共振 ； 電解液

並列摘要

Liquid NMR can quantitatively analyze the composition of the components in a mixture thermodynamically without affecting the sample, and can analyze the three-dimensional structure of molecules from a microscopic point of view, and can capture the dynamic behavior of molecules in real time. Quantitatively, firstly, the quantitative method must be established and the error must be confirmed to be within acceptable limits. Secondly, we divided this study into two major directions, namely, chemical thermodynamics and chemical kinetics: thermodynamics is aimed at the ratio of mixture components. For the quantitative analysis, the lithium concentration of lithium was converted to fluorine concentration and compared with the fluorine spectrum of the organic carbonate solvent FEC to obtain the concentration of FEC, and finally the hydrogen spectrum was used to quantify the concentrations of the five solvents and lithium components. In the case of Acac, a microscopic study was conducted to investigate the conversion of concentrations of the same molecular structure, and to explain the magnitude of the intermolecular conversion mechanism. The results of the variable temperature experiments brought into the Van’t Hoff equation showed that the main reason for the structural interconversion of Acac is energetic. From the hydrogen spectrum, carbon spectrum, oxygen spectrum, solvent effect, variable temperature experiment, hydrogen-deuterium substitution experiment, the substituent effect in the literature, and the oxygen spectrum results of FOD, we determined that the energy factor that stabilizes the enol isomers as planar molecules is the resonance energy.

並列關鍵字

qNMR ； Electrolyte

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