化学师范专业二组分凝聚体系相图绘制实验绿色化改进

针对化学师范专业开设的经典物化实验"二组分金属相图的绘制"在教学中存在的金属样品融化温度高,同时金属样品挥发易污染环境等问题进行了绿色化改进。用熔点较低的有机化合物如十六醇、硬脂酸代替熔点高挥发性大的金属铅、铋,用常规的步冷曲线法绘制了十六醇-硬脂酸二组分绿色化凝聚体系的T-w相图(w十六醇=55.20%时形成最低共熔物,其最低共熔温度为43.8℃);用差示扫描量热仪(DSC)测定并验证了其最低共融点的相变温度和相变焓(最低共熔温度为42.5℃,其相变焓为157 J.g-1)。同时探讨了该二元有机样品的质量对其步冷曲线的影响。改进后的有机凝聚体系相图绘制操作方便,同样能达到二组分金属相图的实验要求,可以促进其他专业的物理化学相图的实验教学。

Green Improvement of Phase Diagram Drawing Experiment of Two-component Condensing System in Chemical Teachers' Major

Aiming at the problems in the classical physicochemical experiment "two-component metal phase diagram"in chemistry teacher training major, such as high melting temperature of metal sample, environmental pollution and so on, the experiment was improved. Organic compounds with low melting point, such as hexadecanol and stearic acid, were used to replace lead and bismuth with high melting point, conventional cooling curve method was used to draw hexadecanol and stearic acid two-component green condensed phase diagrams of T-w system; Differential Scanning Calorimetry (DSC) was used to determine and verify the lowest melting point of phase transition temperature and phase transition enthalpy. At the same time, the influence of the quality of two organic samples on the step cooling curve was also discussed. The improved phase diagram of organic condensing system was easy to draw, and the experimental requirements of two-component metal phase diagram were also achieved