咖啡因的升华装置的优化和形象化展现

Improvement of the Sublimation of Caffeine and Vivid Presentation

“茶叶中咖啡因的提取实验”是有机化学的一个经典实验。对传统的升华装置进行了改进，让升华实验更加简单高效，并且能够看到咖啡因晶体聚集和长大的过程，该装置便于咖啡因的收集，能对所收集的咖啡因进行定量计算，同时增加了采用薄层色谱法对浓缩液中咖啡因进行定性鉴定的实验环节。改进的实验丰富了实验内容，降低了实验可能的失误，提高了实验的安全性，创造性地运用实验室的显微熔点仪和智能手机成功地对咖啡因晶体的形貌进行了拍摄，增加了实验的趣味性。

Isolation of caffeine from tea leaf is one of the classic experiments in organic chemistry experiments. In this study, the traditional sublimation apparatus was changed to be more simple and efficient. Meanwhile, the aggregation and growth of the crystal of caffeine can be ob- served directly. The amount of caffeine can be collected and calculated easily. The thin layer chromatography was used to determine the components in the extracting solution. The new experiment process enriches the experiment lesson and decreases the possibility of mistake. It is sa- fer than the traditional one. Furthermore, the conjunctive use of microscopic melting point meter and smart phone successfully photographed the morphology of the caffeine crystal and bring the interest to this classic experiment.