Detection of water–polar solvent interaction using melting of a eutectic

Simultaneous XRD-DSC Measurements of Water-2-Propanol at Sub-Zero Temperatures

“…As a result, the melting temperature and melting enthalpy of the eutectic for 0.05-alcohol molar-fraction solutions were almost constant, regardless of the ultrasonic treatment, while the melting enthalpy of 0.10-alcohol molarfraction solutions fell to 81% (ethanol) and 46% (1-propanol) of the pretreatment value. 12 These results agree with the data from 17 O NMR of water and the absorption peak at 1150 nm at the near-infrared spectrum for free water, suggesting that the water-polar solvent interaction can be investigated by examining the melting behavior of a eutectic of a polar solvent and water using sensitive DSC. 12 These solutions show two endothermic peaks in the DSC heating trace: one due to the melting of ice, and the other due to melting of the eutectic.…”

“…12 These results agree with the data from 17 O NMR of water and the absorption peak at 1150 nm at the near-infrared spectrum for free water, suggesting that the water-polar solvent interaction can be investigated by examining the melting behavior of a eutectic of a polar solvent and water using sensitive DSC. 12 These solutions show two endothermic peaks in the DSC heating trace: one due to the melting of ice, and the other due to melting of the eutectic. On the other hand, aqueous solutions of 2-propanol show an additional melting peak in addition to those for ice and the eutectic.…”

Analysis of Water State and Gelation of Methylcellulose Thermo-reversible Hydrogels by Thermal Analysis and NMR

“…23 Na NMR measurements were carried out at 303, 313, 323, 333, and 343 K with the spectrometer operating at 104.72 MHz for 23 Na. 23 Na spectra were recorded at a natural abundance of the 23 Na isotope. A NaCl D2O solution was used as the external reference.…”

“…22 In the case of ethanol or 1-propanol aqueous solutions, the water-alcohol interaction can be detected by the examination of the melting enthalpy of a eutectic of alcohol and water. 23,24 With heating, the MC-alkali chloride-water system forms a thermo-reversible gel. Alkali chloride aqueous solutions form a eutectic of alkali chloride and water, and amino acids, sugars, and some organic compounds dissolved in eutectics of salt and water.…”

“…[25][26][27] The melting behavior of these eutectics can be investigated by DSC, and the results obtained from DSC are in good agreement with those obtained by near infrared spectroscopy (NIR) or 17 O nuclear magnetic resonance (NMR). 20,23,27 In this study, we focused on the gelation and water structure of MC hydrogels containing PEG and salt. As compared to the anions, the cations have been reported to exhibit lesser effects on MC solutions.…”