1-甲基-2,4-苯二脲的合成、表征及定量分析

Preparation,Characterization and Quantitative Analysis for Toluene-2,4-Bisurea

以甲苯二异氰酸酯(TDI)和氨气为原料、丙酮为溶剂,合成了1-甲基-2,4-苯二脲(2,4-TBU),并建立了其与副产物1-甲基-2,6-苯二脲(2,6-TBU)两种同分异构体的分离方法;采用熔点测定、薄层色谱、FTIR、NMR和元素分析等方法对2,4-TBU的结构进行了表征;在高效液相色谱分析中,采用外标法建立了2,4-TBU的定量分析方法。测得2,4-TBU的质量浓度在3.0～12.0mg/L内与峰面积呈现良好的线性关系,回收率为99.0%～100.5%,相对标准偏差小于等于0.98%;该合成反应中,TDI完全转化,2,4-TBU和2,6-TBU的收率分别为80%和20%。建立了2,4-TBU定量分析方法,该方法操作简单、灵敏度高、准确性和重复性好,为尿素法合成甲苯-2,4-二氨基甲酸甲酯的研究奠定了基础。

Toluene-2,4-bisurea （ 2,4-TBU ）, which could be used in preparation of toluene-2,4- dicarbamate （TDI）, was synthesized from toluene diisocynate and ammonia with acetone as the solvent. The synthesized products 2,4-TBU and toluene-2,6-bisurea（2,6-TBU） which was the isomer of 2,4-TBU were separated. The synthesized 2,4-TBU was characterized by means of melting point determination, thin-layer chromatography, FFIR, NMR and elemental analysis. A high performance liquid chromatography （HPLC） method with the external standard method was established to analyze 2, 4-TBU quantitatively. The results showed a good linear relationship of the peak area with the sample concentration in the 2,4~TBU concentration range of 3.0 - 12.0 rag/L, and the 2,4-TBU recovery and the relative standard deviation reached 99.0% - 100.5% and less than 0.98%, respectively. In this synthesis reactions, TD! transfirmed completely. The yield of 2,4-TBU and 2,6-TBU were 80% and 20%, respectively.