5-氰基-4-氨基咪唑的合成与热性能

Synthesis and Thermal Behavior of 5-Cyano-4-Aminoimidazole

摘要:

咪唑基含能化合物是目前高能化合物的重要研究方向，而5-氰基-4-氨基咪唑是设计、合成新型咪唑联四唑类高能高氮化合物的关键中间体。以5-甲酰胺基-4-氨基咪唑（AICON）为原料，经其与三氯氧磷（POCl3）的脱水反应获得了5-氰基-4-氨基咪唑（AICN），通过优化反应体系、反应温度、反应时间以及物料物质的量比，使得AICN的收率>65%，纯度（HPLC）>99.5%。此外，采用NMR、IR和元素分析对其进行了结构确征，利用热重分析法研究其热性能。结果表明：AICN的最佳反应条件为以POCl3为脱水剂，n(AICON)：n(POCl3)为1:10，反应升温模式为先快速升温至80~85 ℃，维持反应30 min，然后降温至70~75 ℃，维持反应1~1.5 h；AICN在40~1000 ℃温度区间存在两个失重过程，对应的热分解温度区间分别为40~400 ℃和400~1000 ℃、热失重分别为19.8%和60.7%、热分解峰温分别为256.5和698.4 ℃，表明其具有良好的热稳定性。

Abstract:

Imidazole based energetic compounds are one of the important directions on high energy compounds, and 5-cyano-4-aminoimidazole is the key intermediate for the design and synthesis of novel tetrazoyl imidaz-ole high energy and high nitrogen content compounds. With 5-carboxamide-4-amino imidazole (AICON) as raw material, the target compound 5-cyano-4-aminoimidazole (AICN) was obtained by its dehydration reaction with phosphoryl trichloride (POCl3). Through optimization of reaction system, reaction tempera-ture, reaction time and molar ratio, the yield and HPLC purity of AICN could achieve higher than 65% and 99.5%, respectively. Besides, the target compound was characterized by NMR, IR and element anal-ysis, and its thermal properties were investigated by TG. Results showed that the optimum reaction condi-tions was as follows: taking POCl3 as dehydrant, n(AICON) : n(POCl3) was 1:10, and reaction heating mode was that the reaction temperature rised rapidly to 80-85 ℃, maintained for 30 minutes, then de-creased to 70-75 ℃, and maintained for 1-1.5 h; there were two mass loss stages of AICN existed in the range of 40-1000 ℃, the corresponding decomposition temperature regions were 40-400 ℃ and 400-1000 ℃, the corresponding mass losses were 19.8% and 60.7%, and the peak values of thermal de-composition temperatures was 256.5 ℃ and 698.4 ℃, respectively, which indicated that 5-cyano-4-aminoimidazole had good thermal stability.