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    高師機構典藏 NKNUIR > 理學院 > 化學系 > 博碩士論文 >  Item 987654321/15387
    Please use this identifier to cite or link to this item: http://ir.nknu.edu.tw/ir/handle/987654321/15387


    題名: 2(S)-[2(R)-乙基己氧基]丙酸之合成及含其之液晶化合物
    Authors: 吳錦梅
    Chin-Mei Wu
    貢獻者: 蔡文亮;鄭寶樹;張德洲
    Wen-Liang Tsai;Pao-Swu Cheng
    Keywords: 鐵電性液晶;自發極化值
    Date: 2001-02-08
    Issue Date: 2011-05-31 10:28:47 (UTC+8)
    Abstract: 為了深入地研究鐵電性液晶分子所含掌性末端基中第二個掌性中心對液晶物性的影響,本論文從消旋的2-乙基己酸經光學分割、還原反應和碘化反應製得(R)-1-碘-2-乙基己烷(5),在Ag2O的作用下它和(S)-乳酸乙酯經由醚化反應連結成掌性有機酸乙酯6,再經皂化反應就得到具有兩個不對稱中心的新穎有機酸7(2(S)-[2(R)-乙基己氧基]丙酸)。
    掌性有機酸7與含?環的酚化合物2A經由酯化反應,可以鍵結成新穎的鐵電性液晶8A,其液晶相順序為K─SC*─SA─I,掌性層列C相溫度為58℃-19℃,自發極化值為43 nC/㎝2(48℃);而掌性有機酸7與含聯苯環的酚化合物2B則可鍵結成另一個新穎的鐵電性液晶8B,其液晶相順序為K1─K2─ SC*─N*─I,掌性層列C相溫度為106℃-63.7℃,自發極化值為96 nC/㎝2(96℃)。
    將其結果與先前的研究結果25、27比較,我們發現:(1)核心分子的結構對於液晶分子的液晶相順序、掌性層列C相的溫度範圍和自發極化值的大小有絕對的影響。(2)第二個掌性中心的立體障礙會影響液晶分子的構形,使得自發極化值有明顯的變化。
    將其結果與先前的研究結果34比較,(S,R)form 比(S,S)form自發極化值少,此結果符合Walba等人26提出的解釋模型的預測。
    A new chiral organic acid 7, 2(S)-[2(R)-ethylhexoxyl] propionic acid ,was synthesized and used as a chiral moiety for the preparation of ferroelectric liquid crystals. The chiral starting material, (R)-1-iodo-2-ethylhexane 5, was synthesized from racemic 2-ethylhexanoic acid by optical resolution, reduction and iodination. The new chiral propionic ester 6 was prepared by the etherification of natural ethyl lactate with 5 in the presence of Ag2O. After saponification of 6 the new chiral propionic acid 7 was formed.
    The new ferroelectric liquid crystal 8A was synthesized by the esterification of the new chiral organic acid 7 and the phenolic derivative containing naphthalene ring2A.
    The liquid crystal phase sequence of the compound 8A is K─SC*─SA─I. Its temperature range of SC* phase is from 58℃ to19℃ and its Ps value is 43 nC/㎝2 at
    48℃. The other new ferroelectric liquid crystal 8B was synthesized by the esterification of the new chiral organic acid 7 and the phenolic derivative containing biphenyl ring2B. The liquid crystal phase sequence of compound 8B is K1─K2─ SC*─N*─I. Its temperature range of SC* phase is from 106℃ to 63.7℃ and its Ps value is 96 nC/㎝2 at 96℃.
    Comparing these results with the prior research results25,27, two key points of the work are worth noticing:
    (1)The liquid crystal phase sequence, the temperature range of SC* phase, and the spontaneous polarization are sensitive to the core structure.
    (2)The size of the substituent at the second chiral center could affect the conformation of the liquid crystal compounds and therefore their spontaneous polarization may also be changed.
    Comparing these results with the prior research results34, the spontaneous polarization of the (S,R)form is lower than that of the (S,S)form. The result confirms the predicton of the model.
    Appears in Collections:[化學系] 博碩士論文
    [化學系] 鄭寶樹

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