均二甲脲合成中间体的提纯工艺优化及结构表征

Optimization in Purification Process of Intermediate in 1,3-Dimethylurea Syntheses and Its Structure Characterization

在合成均二甲脲的过程中,发现一种未知中间体。利用薄层色谱对该中间体进行鉴别,采用响应面法对其柱层析提纯工艺进行优化,并对其结构进行表征。结果表明,该中间体最佳提纯工艺条件为:氯仿体积分数85%、硅胶量80 g、体积流量30 mL·min^(-1),在此条件下,中间体实际产率可达24.23%;中间体的分子量为105,熔程为98~99℃;一甲基脲可能与甲胺直接生成中间体,中间体再经脱氨转化为均二甲脲。该研究为均二甲脲合成的机理研究和工艺改进提供了理论基础。

During the syntheses of 1,3-dimethylurea,we found an unknown intermediate.Moreover,we identified the intermediate by thin-layer chromatography(TLC),optimized the column chromatography purification process of the intermediate by response surface methodology,and characterized its structure.The results show that the optimal purification conditions are determined as follows:the volume fraction of chloroform of 85%,the silica gel amount of 80 g,and the volume flow rate of 30 mL·min^(-1).Under above conditions,the actual yield of the intermediate can reach 24.23%.The molecular weight of the intermediate is 105,and the melting range is 98-99℃.Methylurea and methylamine can form the intermediate directly,and then the intermediate can be converted to 1,3-dimethylurea by deamination.The study provides a theoretical basis for the mechanism study and process improvement of 1,3-dimethylurea syntheses.