差示扫描量热法表征氯化镁乙醇醇合物结构

摘要

Magnesium chloride–ethanol adducts (MgCl2·nEtOH) prepared over a composition range of n=1.5 to 2.8,were studied with differential scanning calorimetry. These adducts comprised of two stable compounds,MgCl2·2.8EtOH and MgCl2·1.5EtOH,showing endothermic peaks at 115℃ and 155℃ respectively. In addition,the melting point of the magnesium chloride–ethanol adduct which was very sensitive to water would decrease if trace moisture was present in the adduct. And the characteristic peak of the adduct containing trace moisture and MgCl2·2.8EtOH was observed at 100℃. Moreover,during the dealcoholation of the adducts containing trace moisture with EtOH/MgCl2 molar ratio from 1.55 to 2.64,pure MgCl2·2.8EtOH was removed firstly and then the compound formed by trace moisture and MgCl2·2.8EtOH was removed. However,water was not removed all the way.%采用差示扫描量热法（DSC）研究了EtOH/MgCl2的摩尔比在1.5～2.8的氯化镁乙醇醇合物的结构。研究表明，该区间的氯化镁乙醇醇合物存在两种稳定的组分，经推断这两种组分分别是 MgCl2·2.8EtOH 和MgCl2·1.5EtOH，它们的熔融峰值分别在115℃和155℃附近，该区间的氯化镁醇合物是由这两种稳定的组分组成的混合物。另外，氯化镁醇合物的熔点对水分很敏感，微量的水分会使醇合物的熔点降低。热分析结果显示，在MgCl2·2.8EtOH醇合物中存在微量的水分时会在100℃形成特征峰。对具有微量水分且EtOH/MgCl2的摩尔比在1.55～2.64的氯化镁醇合物进行减压脱醇时，首先减少的是MgCl2·2.8EtOH组分，其次是MgCl2·2.8EtOH与微量水分形成的组分，并且没有水分被脱除掉。