Acta Phys. -Chim. Sin. ›› 2006, Vol. 22 ›› Issue (05): 638-643.doi: 10.3866/PKU.WHXB20060524

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The Influcence of Alcohol Cryoprotec-tants on Eutectic Crystallization of NaCl Aqueous Solutions Studied by DSC

ZHOU Guo-Yan;HU Tong-Ji;GAO Cai;HUA Ze-Zhao   

  1. Institute of Cryomedicine and Food Refrigeration, Shanghai University of Science and Technology, Shanghai 200093, P. R. China
  • Received:2005-09-28 Revised:2006-01-06 Published:2006-04-28
  • Contact: ZHOU, Guo-Yan E-mail:efly_snow@163.com

Abstract: In order to investigate the effect of cryoprotective agent(CPA) on the eutectic crystallization of salt solution,differential scanning calorimetry (DSC) is used to study the eutectic phenomena of NaCl aqueous solutions with different concentrations of glycerol, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, and dimethyl sulfoxide.It is found that the eutectic crystallization is a super-cooling and random process. Cryoprotective agent can restrain the eutectic crystallization of NaCl aqueous solutions. The higher the concentration of cryoprotective agents, the less the enthalpy of eutectic crystallization and the bigger the capability of restraining the eutectic crystallization. The restraining effects of cryoprotective agents on eutectic crystallization are different. The best is glycerol and then is ethylene glycol, 1,2-propylene glycol, and 1,3-propylene glycol, respectively. The restraining capability of alcohols is largely determined by the ratio of molecular weight to number of hydroxyl group, and affected by the number of methyl group as well. The capability of dimethyl sulfoxide to restrain the eutectic phenomena of NaCl aqueous solutions is similar to that of ethylene glycol. It is also found that the glass transition and devitrification phenomena take place during the heating process.

Key words: Alcohol cryoprotective agent, Differential scanning calorimetry, Eutectic crystallization, NaCl, Dimethyl sulfoxide