非等温条件下零下温度下水-乙二醇体系中的相变

On phase transitions in the water-ethylene glycol system at subzero temperatures under non-isothermal conditions.

作者信息

Zinchenko A V, Zinchenko V D

机构信息

Institute for Problems of Cryobiology and Cryomedicine of the National Academy of Sciences of Ukraine, Kharkov, 61015, 23, Pereyaslavskaya str., Kharkov, Ukraine.

出版信息

Cryo Letters. 2001 May-Jun;22(3):191-8.

PMID:11788859

Abstract

The dynamic phase diagrams of the water-ethylene glycol (EG) system have been plotted at the warming rate of 0.4 degrees C/min(-1) after cooling of samples down to -196 degrees C by quenching in liquid nitrogen or slow cooling at the rate of approximately 0.15 degrees C/min(-1). The melting of two stable eutectics at the temperatures of -42.7 degrees C and -48.7 degrees C and the metastable eutectic at -63 degrees C was observed. Hydrates 1:1 crystallized separately from ice during warming both after quenching and after slow cooling. Glass devitrification and EG:3H(2)O hydrate melting took place during warming of the samples after quenching but these thermal features were absent after slow cooling in the EG concentration range of 42.0 - 63.5 weight percent. The notions about two-stage mechanism of ice nucleation in EG aqueous solutions might be critically revised

摘要

通过在液氮中骤冷或按约0.15℃/min⁻¹的速率缓慢冷却，将样品冷却至-196℃后，以0.4℃/min⁻¹的升温速率绘制了水-乙二醇（EG）体系的动态相图。观察到在-42.7℃和-48.7℃温度下两种稳定低共熔物以及在-63℃下亚稳低共熔物的熔化。在骤冷和缓慢冷却后的升温过程中，1:1水合物均与冰分别结晶。在骤冷后样品升温过程中发生了玻璃析晶和EG:3H₂O水合物熔化，但在42.0 - 63.5重量百分比的EG浓度范围内缓慢冷却后，这些热特性不存在。关于EG水溶液中冰成核的两阶段机制的观点可能需要严格修正。