- 學位論文
應用核磁共振技術探討BMI與BTA在 DMF溶劑中之反應機制
NMR Study on the reaction mechanism of BMI and BTA in solvent DMF
摘要
液態核磁共振技術是一種用於分析分子級微觀化學結構的方法。結合核磁共振圖譜的化學位移 (chemical shift) 、J-偶合 (J-coupling) 、定量積分值 (quantitative integration) 、擴散係數值 (Diffusion coefficient) 、二維相關頻譜 (two-dimensional correlation spectroscopy) 等依功能而設計的實驗結果可推論出樣品分子的立體結構。液態核磁共振技術具備： (一) 多樣性脈衝程序、 (二) 高解析度 (NMR可分辨 < 1 Hz的能量解析度，1 cm1＝3×1010 Hz) 、 (三) 分辨混合物 (利用COSY脈衝程序或依據不同的Diffusion coefficient值) 、 (四) 可同時定性及定量決定分子特性的特點、 (五) 可應用在動力學方面的探討。藉由反應前後反應物與生成物的圖譜結果可推論化學反應時進行的反應機制。 本篇研究雙馬來亞醯胺 (4,4’-Bismaleimidodi-phenylmethane) 和巴比妥酸 (Barbituric acid) 在二甲基甲醯胺 (N,N-Dimethylformamide) 溶劑中，進行反應過程的反應機制探討及產物定量。文獻中曾提到雙馬來亞醯胺及巴比妥酸可能進行之反應機制有:自身聚合反應 (homopolymerization reaction[1]) 、麥可加成反應 (Michael addition reaction[1]) 、自由基反應[2] (Free radical reaction) ，所以本篇首先探討反應物在此反應條件下自身反應的可能，進一步設計實驗AIBN自由基起始劑加入反應物當中進行自由基反應，再將結果和本篇研究之BMI-BTA在DMF下反應後之圖譜比較，確認排除自身反應以及自由基反應，從核磁共振實驗中確認反應機制為Michael Addition，並進一步確認產物鍵結。本篇利用核磁共振技術佐以其他測量技術 (GPC，MS) 對BMI-BTA聚合物進行分子結構鑑定，進而推導其反應機制，並希望依此改進製程，以期未來針對BMI-BTA聚合反應做改質、微觀調控，並依其特定在不同領域之應用。
並列摘要
Nuclear magnetic resonance technology can confirm the thermodynamics molecular structure of the sample by chemical shift, J-coupling, quantitative integration, and diffusion coefficient. Liquid nuclear magnetic resonance has the following characteristics: high resolution (1 cm1 equals to 3*1010 Hz in resolution) , mixture compounds identification ( by using COSY or Diffusion coefficient experiments) , qualitative and quantitative analysis simultaneously, and diversified pulse sequence ( 1D and 2D homonuclear and 2D heteronuclear pluse sequence) . Therefore, NMR is important to the molecular-level identification. Beside the identification of the molecular structures, NMR can do dynamic study, infers to the possible reaction mechanisms by suspecting the spectrum of reactant active sites and structures of products. In this study, we proposed possible mechanisms through the polymerization which BMI ( 4,4'-Bismaleimidodi-phenylmethane) reacted with BTA ( Barbituric acid) at 90°C in DMF ( N,N-Dimethylformamide) solvent system. In previous studies, BMI is able to udergo the mechanism of homopolymerization reaction[1], Michael addition reaction[1], Free radical reaction[2]. This thesis identified the self-reaction of reactants in DMF solvent system at first; As the consequence, we designed radical reactions by AIBN reacting with reactants in DMF, and then compared with structure of BMI-BTA products and the possible mechanism by NMR-based technology. The result represents the mechanism of BMI-BTA in DMF is Michael addition, not self-reaction or radical reaction. We identified the chemical shift of product, and hoped to improve reaction processes and modify BMI-BTA products in order to apply to different domains in the future.