理論計算在化學上的應用 : 有機動力學分割反應與電極表面的離子液體的電腦模擬

The applications of theoretical calculations in chemistry: modeling the organic kinetic resolution reaction and ionic liquids at electrode surfaces

黃永宜(Huang Yung-Yi)

指導教授 ： 蔡明剛

國立臺灣師範大學/理學院/化學系/碩士(2021年)

https://doi.org/10.6345/NTNU202100969

摘要

本篇論文分為兩個部分，第一部分我們主要針對 Kinetic Resolution reaction (KR-reaction) 的部分及有機催化反應循環，利用理論計算進行深入的探討。眾所 皆知的事實是實驗室合成的藥物多為外消旋混合物，而市售的藥品也經常就以此種型態售出；但這樣的藥物可能存在著一些不必要的副作用以及降低藥效的可能。因此近年來許多人在藥物的分離上有所著墨，但在進行實驗的過程我們經常無法看到微觀世界中的分子行為以及藥物分離機制。本論文的第一部分將深入探討整個有機催化反應循環及 KR-reaction 的每一個步驟之反應機構，並透過理論模擬的方式補足實驗上所無法看到的一些化學及物理現象。我們成功的在實驗中觀察到許多微觀世界中的催化反應，也進而提出及證實了合理之反應機構。第二部分則透過多尺度模擬探討固態電極表面及離子液體之間的離子傳導行為。隨著人類平均壽命的上升，我們更為重視生活的質量，此外全球暖化的影響，造成天氣日漸炎熱，使用電需求大大上升，在能源生產與儲存的技術上大受挑戰。其中電化學儲能技術被許多人提出來研究，電化學的電池儲能技術最重要的環節就是中間離子傳導的過程，而如何挑選電池中間的隔離膜成為重要的課題；部分研究已證實 兩 性 離 子 液 體 所 合 成 出 來 的 聚 合 兩 性 高 分 子 薄 膜 (amphiphilic polymer membrane)所包含帶部分正電的咪唑以及帶部分負電的磺酸根可以有效幫助離子傳導並提高電池穩定度。本研究想透過理論模擬探討電化學電池中隔離膜在離子傳導過程中扮演著甚麼樣重要的角色，也想比較不同的離子液體對離子傳導所造成的影響。我們挑選了正負電荷完全分離與正負電荷於同一條碳鏈的結構，深入探討其對離子傳導的影響，並透過多尺度的理論模擬從分子古典力學到量子力學研究有關離子傳導行為的變化。最終研究結果顯示一維的水分布結構將有效幫助離子傳導之行為進而提高離子傳導率。

關鍵字

電子密度泛函理論 ； 有機動力分割反應 ； 離子液體 ； 兩性高分子薄膜

並列摘要

This paper is divided into two parts. In the first part, we mainly focus on the Kinetic Resolution reaction (KR-reaction) and the whole catalytic reaction cycle. We use theoretical calculations to discuss organocatalytic reaction cycles. A well-known fact is that many drugs are synthesized in the laboratory and those are racemic mixtures, however, may have some unnecessary side effects with the possibility of reducing the efficacy of the drug. Therefore, it is important to separate the enantiomers. In the process of experiments, we often cannot microscopically see the molecular behavior and drug separation mechanism. In the first part, we applied theoretical simulations to investigate these chemical and physical phenomena. Finally, we successfully confirmed and proposed reasonable reaction mechanisms. In the second part, ionic liquid moiety of the imidazole-based membrane has shown the enhanced performance for the proton exchange efficiency of the high temperature fuel cell. Typically, the tertiary amines and sulfonate groups appear to play important roles in facilitating the proton transfer processes. In this study, we conducted a multi-scaling approach to investigate the interplay of these ionic-liquid functional groups and the hydrogen bond network near the electrode–electrolyte interface. Two polymer models were built to conceptually represent the cationic and anionic moieties interactions, one containing the well separated charge groups and the other containing a zwitterionic side chain. The classical molecular simulations were carried out to sample the possible electrolyte-water morphology with accounting the electrode surface interactions. The collected representatives for these flexible membrane structures were subsequently simulated by Density Functional Theory (DFT) to identify the proton transfer processes. The electric field effect was taken into account in the classical dynamic calculations to monitor the field-induced electrolyte-water-membrane responses.

並列關鍵字

DFT ； Kinetic Resolution reaction ； ionic liquid ； amphiphilic polymer membrane

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