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

• Main Authors: Hsiao-Ching Kuo, 郭小靖
• Other Authors: Hsi-Wei Jia
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/79551741544785374064

碩士 === 中原大學 === 化學研究所 === 102 === 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.