3,5-二硝基-1-氧杂-3,5-二氮杂环己烷的分离、热分解及硝解机理分析

Separation and thermal decomposition of 3,5-dinitro-1-oxa-3,5-diazacyclohexane and the nitrolysis mechanism

为掌握乌洛托品的硝解机理,研究了直接法硝解乌洛托品制备黑索今(RDX)的废水。实验通过乙酸乙酯萃取富集废水中的副产物,水洗至中性,浓缩,用薄层色谱法分析,展开系统为:丙酮/二氯甲烷/冰乙酸=1/6/0.1。采用硅胶柱柱层析法分离,丙酮/二氯甲烷梯度洗脱,分离得到两种物质,一种物质通过熔点、红外、核磁比对确认为1,3,5-三硝基-1,3,5-三氮杂环己烷(RDX);另一种物质采用红外光谱、核磁、质谱、元素分析及单晶衍射等分析方法进行结构表征,认定其为3,5-二硝基-1-氧杂-3,5-二氮杂环己烷。用DSC-TG技术研究了3,5-二硝基-1-氧杂-3,5-二氮杂环己烷热行为,结果表明该化合物是一种熔点低、热稳定性好的化合物,对主要副产物的分离和结构鉴定为直接法硝解反应机理提供了可靠的实验依据。

In order to understand the nitrolysis mechanism of hexamethylenetetramine,we studied the waste water from the preparation of hexogeon（RDX） by nitric acid nitration. The byproducts were enriched by extraction with ethyl acetate,washed with water to neutral,and concentrated. Then they were analyzed by thin layer chromatography（TLC） with the developing solvent of acetone/dichloromethane/glacial acetic acid with a（volume） ratio of 1/6/0.1. Finally silica gel column chromatography was applied to separate the stable byproducts,which was then eluted by mixtures of acetone and dichloromethane with different composition. RDX was confirmed as one of the products by melting point,IR and NMR analysis. The other one product obtained was characterized through IR,NMR,MS,elemental analysis and single crystal diffraction,and then identified as 3,5-dinitro-1-oxa-3,5-diazacyclohexane. The DSC-TG technique was used to investigate the thermal behavior of 3,5-dinitro-1-oxa-3,5-diazacyclohexane,which showed a pair of sharp peaks at 375.85K（melting） and 519.05K（decomposition）,indicating that it is a low melting point compound with good stability. The separation and structure identification of main byproducts provided some reliable proofs for the mechanism of RDX obtained by direct nitration.