直接法制备黑索今工艺中废水的成分研究及硝解机理分析

Composition of waste water and nitrolysis mechanism during RDX preparation by direct nitration

为了更好地改进发烟HNO3硝解乌洛托品制备黑索今(RDX)的生产,研究了乌洛托品经发烟HNO3硝解后废水中的副产物,实验选用网状大孔树脂GDX-102吸附废水中的副产物,用二氯甲烷和乙腈(二氯甲烷/乙腈=90/10)进行洗脱、浓缩,然后采用薄层色谱分离,薄层色谱的展开系统为:丙酮/二氯甲烷/石油醚=1/3/6,分离得到了两种物质,并采用红外光谱、核磁、质谱和元素分析等分析方法对产物进行了结构表征,认定其为1,3,5-三硝基-1,3,5-三氮杂戊烷和1,5-二硝酰氧基-2,4-二硝基-2,4-氮杂戊烷。发烟HNO3硝解乌洛托品,反应复杂,副产物多,本文通过分离得到的两种副产物对其硝解反应的机理进行了分析,乌洛托品先迅速硝解生成乌洛托品二硝酸盐,再迅速硝化形成中间产物黑索今母体和DPT,逐渐生成主要产物RDX和少量HMX,而随着反应的进行,体系的氧化性增强,环状化合物则被破坏断裂成直链化合物生成1,3,5-三硝基-1,3,5-三氮杂戊烷和1,5-二硝酰氧基-2,4-二硝基-2,4-氮杂戊烷。

In order to improve the preparation of RDX through nitrolysis of hexamethylenetetramine by concentrated nitric acid, the byproducts in wastewater after nitrolysis were studied. The byproducts were first absorbed through reticular macroporous resin GDX-102, and then eluted by a mixture of methyl chloride and acetonitrile with a （ molar or volume ） ratio of 90： 10. Last, the byproducts were concentrated and separated in thin layer chromatography （ TLC ）, the developing solvent of which was acetone/methylene chloride/petroleum ether with a （ molar or volume ） ratio of 1 ： 3 ： 6. IR, NMR, MS, and elemental analysis were used to characterize the products obtained, which were recognized as 1,3,5-trinitro-1,3,5-triazapentane and 1,5-dinitro-acyloxy-2,4-dinitro-2,4-azapentane. The nitrolysis reaction of hexamethylenetetramine by concentrated nitric acid was extremely complicated and so many byproducts were produced in this process. The results indicated that nitric acid first transformed hexamethylenetetramine into its dinitrate. The intermediate products of DPT and the precursor of RDX was then formed by rapid nitration of dinitrate, and the main product RDX and little HMX were generated gradually. With the proceeding of reaction and increasing system oxidability, ring compounds were destroyed and broke into straight-chain compounds, such as 1,3,5-trinitro-1,3,5-triazapentane and 1,5-dinitro-acyloxy-2,4-dinitro-2,4- azapentane.