應用多核種核磁共振波譜研究二甲基亞碸與丙酮溶劑性質及結構相異性/溶劑效應對三甲基磷氧作為酸性液體探針分子偵測靈敏度之影響

Multinuclear NMR Measurements for the Investigation of Solvent Characterization and Structural Difference between Acetone and Dimethyl Sulfoxide. / Solvent Effect on the Sensitivity of Liquid Acidity Characterization by Trimethylphosphine Oxide

郭小靖(Hsiao-Ching Kuo)

指導教授 ： 賈緒威

中原大學/理學院/化學研究所/碩士(2014年)

https://doi.org/10.6840/cycu201400786

摘要

液態核磁共振儀為一種分子級分析儀器，本篇論文則主要以異核實驗( 17O、31P )以及1H 擴散 (Diffusion) 實驗並搭配黏度計研究溶劑分子結構及溶劑效應。
實驗將分為兩部分，第一部分為基本溶劑的性質分析，研究二甲基亞碸 (DMSO) 與丙酮 (Acetone) 分子結構差異對其化學與物理性質的影響。兩者的分子式相似，除了中心原子相異外，其餘連接於中心原子上之官能基皆相同，但在沸點、熔點…等物理性質上卻有相當大的差異。為了探討其中因素，本研究先藉由液態 NMR 量測DMSO與Acetone的氫、碳、氧譜及1H 擴散係數互相比較，再以量測一系列含氧溶液樣品之氧譜，研究氧原子與其連接原子核之間的鍵級、分子結構、立體構形…等因素與氧譜化學位移之間的關聯性。本部分研究的氧譜實驗結果中，Acetone約位於576.0 ppm，DMSO則位於18.78 ppm，且C與S原子的電負度差異不大，但在氧譜化學位移卻相差甚遠，從鍵級趨勢上推論，DMSO中的SO鍵可能並非傳統分子結構式所示的雙鍵，而是接近SO電荷分離的類單鍵。而溶劑性質部分則藉由加入離子固體及與H2O混溶的溶劑化結構兩方面研究。從實驗結果可得知DMSO活性端位於氧原子並且其電荷分離程度可破壞水分子間的氫鍵網絡，並且兩者間形成良好的群聚體，使得DMSO與水的共溶液在特定比例下可於150 °C不結凍，形成效用極佳的抗凍劑。
實驗的第二部分則將研究溶劑效應應用於以三甲基磷氧化物作探針分子並以NMR磷譜實驗測量的液體酸酸性鑑定。其酸性鑑定方式可克服原本傳統的酸性鑑定之不足，提供一個更加廣用且靈敏的酸性偵測方式，但溶劑效應仍始終為先前液體酸酸性鑑定中不可忽視的問題，故本論文以質子性與否、極性及Donor number等特性對常用溶劑做分類，並選定五種代表溶劑 (H2O、NMP、Acetone、DEC及ACN) 並配製酸液 (H2SO4、HClO4、Acetic acid、Lactic acid) 作酸性鑑定。實驗結果發現低濃度 (<1M) 酸性溶液以Donor number小的非質子性溶劑較為合適。高濃度 (>1M) 酸性溶液則分為強酸及弱酸部分，強酸部分不論質子性或非質子性，以Donor number大的溶劑較為合適，弱酸部分則以Donor number大的非質子性溶劑較為合適，以上結果可為以TMPO作酸性探針之酸性鑑定提供溶劑選擇的參考依據。

關鍵字

酸性鑑定 ； 三甲基磷氧 ； 溶劑效應 ； 丙酮 ； 二甲基亞碸 ； 核磁共振

並列摘要

Liquid state NMR could be used for molecular-level analysis. There are two major topics in this thesis to study molecular structure and solvent effect mainly by multinuclear NMR experiments (17O and 31P), 1H diffusion experiments and viscosity measurements.
The first topic is solvent characteristic analysis of dimethyl sulfoxide (DMSO) and acetone. The structures of DMSO and acetone is almost the same but center atom. It’s hard to explain the large difference of chemical and physical properties between DMSO and acetone. 1H and  13C of DMSO and acetone are similar but 17O is different (17O, DMSO：18.78 ppm;17O ,acetone：576.0 ppm). 17O of a series of common oxygen-content solvent show 17O is relative to the bond order and bond type. Therefore this study demonstrates the S-O bond of DMSO is not like usually saying as double bond but a single-like bond. The solvent characteristic analysis is studied by adding salts and mixing with water. The results show the activated side of DMSO is on oxygen. The S-O bond of large charge serapration could break H-bond network between water molecules and forms big cluster with water. That’s why DMSO could be a good cryoprotectant.
The second topic is the study of how solvent effect affects sensitivity of liquid acidity characterization by measuring 31P NMR experiments of trimethylphosphine oxide (TMPO). The 31P measurement of TMPO provides a better method to meature acidity and overcomes many problem of traditional liquid acidity characterization. However there is still a major problem on solvent effect. Preparing acidic (H2SO4、HClO4、Acetic acid、Lactic acid) sample solution by choosing five common solvent (water, N-methyl-2-pyrrolidone (NMP), acetone, diethyl Carbonate (DEC), and acetonitrile) according to three solvent properties：(1) Protic or not ;(2) Polarity;(3) Donor number. In conclusion, the proper solvens of liquid acidity characterization by TMPO：for low concentration acidic solution is small donor number aprotic solvent (ex : acetone) ;for high concentration weak acidic solution is large donor number aprotic solvent (ex : NMP);for high concentration strong acidic solution is large donor number solvent (ex : H2O). The study provide a refrence to select proper solvent in liquid acidity characterization by TMPO.

並列關鍵字

acetone ； NMR ； Acidity Characterization ； TMPO ； solvent effect ； DMSO

參考文獻

[5]　Chu, Y.; Yu, Z.; Zheng, A.; Fang, H.; Zhang, H.; Huang, S.-J.; Liu, S.-B.; Deng, F. J. Phys. Chem. C, 2011, 115, 7660

[7]　W. H. Chen, H. H. Ko, A. Sakthivel, S. J. Huang, S. H. Liu, A. Y. Lo, T. C. Tsai, S. B. Liu. Catal. Today, 2006, 116, 111–120

[3]　H. M. Kao, H. Liu, J. C. Jiang, S. H. Lin, C. P. Grey. J. Phys. Chem. B, 2000, 104, 4923

[2]　C. Reichardt, T. Welton. Solvents and Solvent Effects in Organic Chemistry, Fourth Edition. 2011, Weinheim. ISBN: 978-3-527-32473-6

[9]　J. B. Mann, T. L. Meek, L. C. Allen. J. Am. Chem. Soc. 2000, 122, 2780-2783