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研究生:卓志鍵
論文名稱:苯環1,3,5-三取代之盤形液晶分子之合成及性質研究
指導教授:余 良 杰
學位類別:碩士
校院名稱:淡江大學
系所名稱:化學學系
學門:自然科學學門
學類:化學學類
論文種類:學術論文
論文出版年:2001
畢業學年度:89
語文別:中文
論文頁數:85
中文關鍵詞:盤形液晶分子柱狀液晶相
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本研究的目的在探討苯環1,3,5位置取代之盤形分子及其取代基變化對液晶相的影響。合成主要有三系列:系列一為 1,3,5-Tri(4-(m(alkyloxy) benzoyloxy) benzoyloxy) benzene,1,3,5-Tri-(mCnOBB) B ,m表末端烷氧鏈的數目,n表烷氧鏈的碳數。主要以1,3,5-苯三酚和4-氧苯羧酸-4-苯羧酸為核心結構之下,改變尾端碳鏈的長短及個數,其中m = 1,n = 12與16時,液晶相為I—D—K,溫度範圍100℃— 45℃。而m = 3,n = 12與16時,液晶相溫度範圍52.5℃—室溫。其中m = 1與m = 3比較,主要差異在於末端碳氫鏈的數目。後者由於碳氫鏈的增加,使得分子量變大,造成黏度變大。此外,亦造成澄清點溫度下降。當m = 2,n = 12時,化合物為非液晶質。
系列二為 1,3,5-Tri(4-(4-(m(alkyloxy) benzoyloxy) benzoyloxy ) benzoyloxy)benzene,1,3,5-Tri-(mCnOBBB) B。與系列一主要的差異在於每個側鏈基的部分多一個苯羧酸。由於其苯環數目的增加,使得其熔點及澄清點溫度上升,並且使得分子間作用力增加,因此需較長的尾鏈來增加擾動才有助於液晶相的生成。所以,此系列只有m = 1,n = 16及m = 3,n = 12時觀察到液晶相。
系列三為1,3,5-Tri-(4-(m(alkyloxy) benzoyloxy) phenoxycarbonyl) benzene,1,3,5-Tri-(mCnOBP) B。其中m = 1,n = 12與16以及m = 3,n = 12與系列一比較,主要差異是中心單元苯環與側鏈基之間的酯基方向的不同。因為酯基中的羰基(carbonyl group)比較靠近中心苯環,使得偶極-偶極作用力增加,而造成其液晶相有較高的熱穩定性,且系列三之化合物的熔點及澄清點的溫度均較系列一為高。
在混溶測試中發現,每個側鏈末端接一條烷氧鏈之化合物,不論哪個系列彼此均可互溶;但與側鏈末端接三條烷氧鏈之化合物則不互溶。推斷其原因可能是兩者(m = 1及m = 3)化合物所形成之液晶相為不同結構之柱狀液晶相,或者是此兩化合物之化學性質不同所造成。

Discogens consisted of 1,3,5-trisubstituted benzene as the central core with different side arms, and having 3, 6, and 9 peripheral chains were synthesized. Columnar phases, uniaxially negative, were observed for compounds consisted of two or more benzoate units in the side arms along with 3 or 9 peripheral chains ( longer than 12 carbon units), but not with 6 peripheral chains. Phase diagram study shows that the former two are individually miscible with the latter and exhibiting textures resemble those of the pure discogens, but are not miscible with each other with or without the presence of the latter. The immiscibility could be due to different chemical properties of the components, or due to different phase structures.
Series 1, 1,3,5-Tri-(4-(m(alkyloxy) benzoyloxy)- benzoyloxy) benzene homologues ( 1,3,5-Tri-(mCnOBB)B ),where m is the number of hydrocarbon chain in each side arm, and n is carbon number of each chain. Compounds with m = 1, n = 12 or 16 and m = 3, n = 12 or 16 exhibited enantiotropic columnar phases from room temperature to 100℃. But nonmesogens were obtained when m = 2 and n = 12.
Series 2, 1,3,5-Tri-(4-(4-(m(alkyloxy) benzoyloxy) benzoyloxy) benzoyloxy) benzene ( 1,3,5-Tri-(mCnOBBB)B ) exhibited enantiotropic columnar phases when m = 1, n = 16 and m = 3, n = 12. Compared with series 1, each arm has one more benzoate unit, therefore the melting point and clearing point are higher. Longer alkyloxy chain is needed for the formation of columnar mesophase for m = 1.
Series 3, 1,3,5-Tri-(4-(m(alkyloxy) benzoyloxy) phenoxycarbonyl) benzene ( 1,3,5-Tri-(mCnOBP)B ) exhibited monotropic columnar phase for m = 1, n = 12 and enantiotropic columnar phases for m = 1, n = 16 and m = 3, n = 12. Compared with series 1, the ester functional groups near the core are inverted. The clearing points are much higher than those of series 1. This is attributed to the enhancement of core-core interactions due to the resonace structures resulted from the bonding of carbonyl groups with the central benzene ring.

表錄--------------------------------------------------------------------------------------------IV
圖錄---------------------------------------------------------------------------------------------V
液晶相紋理圖錄----------------------------------------------------------------------------IIV
圖譜錄-----------------------------------------------------------------------------------------IX
第一章 序言----------------------------------------------------------------------------------1
1、液晶相的命名---------------------------------------------------------------------------2
2、盤形液晶的分子結構------------------------------------------------------------------6
3、柱狀液晶相的鑑定---------------------------------------------------------------------9
4、研究動機--------------------------------------------------------------------------------16
第二章 合成及結構鑑定------------------------------------------------------------------19
1、使用儀器及廠牌-----------------------------------------------------------------------19
2、使用藥品及廠牌-----------------------------------------------------------------------20
3、合成流程--------------------------------------------------------------------------------22
4、合成步驟--------------------------------------------------------------------------------31
第三章結果與討論------------------------------------------------------------------------47
第四章結論---------------------------------------------------------------------------------58
參考文獻---------------------------------------------------------------------------------------83

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