Phase Diagrams and Water Activities of Aqueous Dicarboxylic Acid Systems of Atmospheric Importance
Phase Diagrams and Water Activities of Aqueous Dicarboxylic Acid Systems of Atmospheric Importance
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DOI：
10.1021/jp805985t
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发表时间：
2008-11-20
影响因子：
2.9
通讯作者：
Palet, Benjamin
中科院分区：
文献类型：
--
作者：
Beyer, Keith D.;Friesen, Katherine;Palet, Benjamin
我们已经研究了液/固相图和水的活动的二元体系的马来酸，dl-苹果酸，谷氨酸，丁二酸，用差示扫描量热法，红外（IR）光谱的薄膜，和电导率分析的饱和溶液。对于每个二元系统，我们报告的测量的冰融化信封，酸溶解信封，和冰/酸共晶温度和组成。利用冰的冰点下降来确定水的活度。此外，在DSC和IR研究中观察到马来酸的不可逆固/固相转变，这可能是由于马来酸的亚稳晶形转化为其最稳定的晶形。在一般情况下，我们发现很好的协议与文献值的温度依赖性的酸溶解度。
We have studied liquid/solid phase diagrams and water activities of the dicarboxylic acid/water binary systems for maleic, dl-malic, glutaric, and succinc acids using differential scanning calorimetry, infrared (IR) spectroscopy of thin films, and conductivity analysis of saturated solutions. For each binary system we report the measurements of the ice melting envelope, the acid dissolution envelope, and the ice/acid eutectic temperature and composition. Water activities have been determined by using the freezing point depression of ice. Additionally, an irreversible solid/solid phase transition for maleic acid was observed in both DSC and IR studies likely due to the conversion of a meta-stable crystal form of maleic acid to its most stable crystal form. In general we find good agreement with literature values for temperature-dependent acid solubilities.