薄层色谱实验改进

Improvement of Thin Layer Chromatography Experiment

薄层色谱实验是有机化学实验教学中的重要内容之一,教材中的教学内容“薄层层析板的制备和混合物的分离”已难以满足日益提升的教学要求,故对其进行改进:首先通过展开剂和混合物的扩散程度实验和单向展开实验,优选了苯甲酰乙酸乙酯(A)与α-乙酰氧基苯甲酰乙酸乙酯(C)混合物最佳展开剂为10:1的石油醚—乙酸乙酯,A的R_(f)值为0.40,C的R_(f)值为0.17;其次设计了以苯甲酰乙酸乙酯为底物,历经α-溴代苯甲酰乙酸乙酯关键中间体合成α-乙酰氧基苯甲酰乙酸乙酯的反应,并利用薄层色谱技术监测反应进程和历程。与传统方案相比,新方案中的展开剂选择、反应监测,有助于激发学生自主探究理论知识的动力,提升学生的科研素质。

The thin layer chromatography(TLC)is the common content in experimental teaching of Organic Chemistry.However,preparation of thin layer chromatography plate and separation of mixtures in the textbook has been difficult to meet the increasing teaching requirements.The following improvements were made:firstly,the diffusion test and unidirectional expansion test were used to screen better feasible spread solvent.Secondly,the synthesis ofα-acetoxy ethyl benzoylacetate from ethyl benzoylacetate through the key intermediateα-bromide ethyl benzoylacetate was designed and TLC was used to monitor this reaction.In this improved experiment,the selecting of better feasible spread solvents and monitoring of reaction process can not only improved students’interest in Organic Chemistry,but also enabled students to prepare themselves for participating scientific research.