Glass-forming tendency and stability of aqueous solutions of diethylformamide and dimethylformamide

摘要: Abstract The glass-forming tendency on cooling and the stability of wholly amorphous state warming aqueous solutions diethylformamide dimethylformamide have been studied by calorimetry. With diethylformamide, only ice formation is observed except at lowest rate 2.5°C/min, where occasionally a hydrate forms also. was up to 10°C/min with 50% diethylformamide. hydrates form even high rates. last melts −47.7°C. thermograms are much more complicated than for For cooling, as well warming, these two compounds, concentrations 40, 45, or (w/w) in water, efficient glycerol ethylene glycol, but less 1,2-propanediol levo-2,3-butanediol. On they comparable DMSO. Pure could not be crystallized, whereas, conversely, pure vitrified. Curiously, glass transition increases then decreases concentration contrary other cryoprotectants, which it always decreases. Diethyl- interesting cryoprotectants if too toxic when added before cryopreservation, case dimethylformamide, one can avoid damage due its hydrates.