Unlike the adverse eff ect caused by the gelation during crystallization process, gelation of cefpiramide sodium was found to provide ideal product properties, such as a larger and more regular crystal shape. The caus...Unlike the adverse eff ect caused by the gelation during crystallization process, gelation of cefpiramide sodium was found to provide ideal product properties, such as a larger and more regular crystal shape. The causes of the gelation phenomenon and the mechanism of gel-crystal transition during the crystallization of cefpiramide sodium were both investigated in this work. The gel was formed due to the strapping of the solvents by the networks of cefpiramide sodium molecules. The whole gel-crystal transition process was divided into the following three stages:(1) when the temperature decreased, the system reached a metastable-state gelation;(2) the initial microcrystal in the gel grew slowly because of the low supersaturation;and (3) the gel fi nally disappeared, and a larger and more regular crystal was formed. The Hansen solubility parameters were used to analyze the eff ects of the solvents on this gelation;the analysis results can serve as guidance for solvent screening in the actual production process.展开更多
Gel is a very diverse system that has pervaded our everyday life in a variety of forms. However, the mechanism of gel formation remains ambiguous. To better understand the mechanism of gel formation, cefpiramide was s...Gel is a very diverse system that has pervaded our everyday life in a variety of forms. However, the mechanism of gel formation remains ambiguous. To better understand the mechanism of gel formation, cefpiramide was selected as model compound to investigate gel formation from molecular level, with the help of experimental research and molecular dynamics simulations. Dynamic light scattering was used to detect the process of the formation of fiber aggregates by the molecules in the gel process. The results indicated that in the process of low molecular weight gels, the molecules coalesce to form a fibrous network structure to wrap the liquid. Attenuated Total Reflectance Fourier Transform Infrared spectrometer and Raman spectroscopy were employed to explore the solute–solute and solute–solvent interactions, which indicated that the solvent molecules (formamide molecules) played a key role in the process of gel formation and the solute–solute interactions played a leading role. Finally, molecular dynamics simulations were employed to reveal the molecular mechanism of gel formation from molecular level.展开更多
基金supported by Tianjin Municipal Natural Science Foundation (No. 16JCZDJC32700)Major National Scientifi c Instrument Development Project (No. 21527812)
文摘Unlike the adverse eff ect caused by the gelation during crystallization process, gelation of cefpiramide sodium was found to provide ideal product properties, such as a larger and more regular crystal shape. The causes of the gelation phenomenon and the mechanism of gel-crystal transition during the crystallization of cefpiramide sodium were both investigated in this work. The gel was formed due to the strapping of the solvents by the networks of cefpiramide sodium molecules. The whole gel-crystal transition process was divided into the following three stages:(1) when the temperature decreased, the system reached a metastable-state gelation;(2) the initial microcrystal in the gel grew slowly because of the low supersaturation;and (3) the gel fi nally disappeared, and a larger and more regular crystal was formed. The Hansen solubility parameters were used to analyze the eff ects of the solvents on this gelation;the analysis results can serve as guidance for solvent screening in the actual production process.
基金support of the National Natural Science Foundation of China(grant Nos.21978201 and 22108196).
文摘Gel is a very diverse system that has pervaded our everyday life in a variety of forms. However, the mechanism of gel formation remains ambiguous. To better understand the mechanism of gel formation, cefpiramide was selected as model compound to investigate gel formation from molecular level, with the help of experimental research and molecular dynamics simulations. Dynamic light scattering was used to detect the process of the formation of fiber aggregates by the molecules in the gel process. The results indicated that in the process of low molecular weight gels, the molecules coalesce to form a fibrous network structure to wrap the liquid. Attenuated Total Reflectance Fourier Transform Infrared spectrometer and Raman spectroscopy were employed to explore the solute–solute and solute–solvent interactions, which indicated that the solvent molecules (formamide molecules) played a key role in the process of gel formation and the solute–solute interactions played a leading role. Finally, molecular dynamics simulations were employed to reveal the molecular mechanism of gel formation from molecular level.
