Editor's note: With the strong support of the National Natural Science Foundation of China, the Ministry of Science and Technology and the Chinese Academy of Sciences, researchers in the colloid, interface and chemical thermodynamics laboratory of the Institute of Chemistry used a special surfactant to form a thermodynamically stable supercritical CO2 / PEG dispersion system), and using this as a medium to prepare highly dispersed gold nanocrystals. This new environment-friendly dispersion system has wide application prospects in the fields of material preparation, chemical reaction, extraction and separation.
Supercritical fluid and polyethylene glycol (PEG) are green media with many unique properties. For example, the physical and chemical properties of supercritical CO2 are very sensitive to changes in temperature and pressure, that is, their properties can be changed without changing the chemical composition. Continuous adjustment with pressure; PEG has the advantages of being non-toxic, harmless, and miscible with many organic and inorganic substances, and its properties can be adjusted by changing the molecular weight. The combination of supercritical CO2 and PEG will produce new properties. However, because the properties of the two are very different, it is difficult to achieve stable dispersion of PEG in supercritical CO2.
Fig. Supercritical CO2 / polyethylene glycol dispersion system
With the strong support of the National Natural Science Foundation of China, the Ministry of Science and Technology and the Chinese Academy of Sciences, researchers in the colloid, interface and chemical thermodynamics laboratory of the Institute of Chemistry used a special surfactant to form thermodynamically stable supercritical CO2 / PEG Disperse system (Angew. Chem. Int. Ed., 2012, 51, 12325-12329, see figure), and use this as a medium to prepare highly dispersed gold nanocrystals.
This thermodynamically stable dispersion system has the following characteristics: the size of PEG microdomains can be adjusted by the content and molecular weight of PEG; the formation and destruction of PEG microdomains can be adjusted by CO2 pressure; by PEG and supercritical CO2 green Solvent composition, etc.
This new environment-friendly dispersion system has wide application prospects in the fields of material preparation, chemical reaction, extraction and separation.
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