Applications Of N₂O₄ In Synthesis Of Polynitro Compounds

Nitro compoundsarea kind of important materials in modern society, react significant roles in pesticide, medicine, printing industries and these compounds are used widely. Similarly, the preparation of nitro compounds is an important direction of synthetic chemistry and requires different methods and reagents. Among these because N₂O₄ exhibits advantages as a versatile reagent such as its application as a multifunctional agent（nitration, nitrosation, and oxidation agent）, it playes an excellent role in the preparation of nitro compounds and their intermediates. In this paper the applications of N₂O₄ in the synthesis of chain, cyclic and cage polynitro compounds were studied.（1） In this paper, ethylene and N₂O₄ were reaction substrates, by optimizing the reaction conditions, we accomplished the addition reaction in a green, safety and efficient way. The products 1,2-dinitroethane, 2-nitroethyl nitrate and 2-nitroethan-1-ol were characterized by FT-IR, NMR, Mass spectrum, elemental analysisand so on. Besides, we simply introduced a kind of reaction that lead nitro group into molecules to improve its energy density- the mannich reaction. And the mannich reaction of 1,2-dinitroethane also were explored in this paper.（2） A series ofring polynitro conpoundswere synthesized through heteroaromatic-oximesreacted with N₂O₄.Firstly we used picolinaldehydereactedwithhydroxylamine hydrochloride to get picolinaldehyde oxime, and then picolinaldehyde oxime reacted with N₂O₄under40 ℃ to get2-（trinitromethyl）pyridineand 4-nitro-2-（trinitromethyl）pyridine in nice productivity. These products were characterized by FT-IR, NMR, Mass spectrum, elemental analysisand so on. Besides,other aromatic heterocyclic-formaldehyde structureswere explored in the same path. N₂O₄ was used to react with 2-formylpyridine oxime,2-thiophenealdehyde oxime,2-furancarboxaldehydeoxime and 2-formylpyrrole oxime to synthesis 2-（trinitromethyl）pyridine, 3,5-dinitrothiophene-2-carbonitrile, 2,3-dinitrofuran and 5-dinitro-1H-pyrrole-2-carbaldehyde respectively under a same reaction condition.（3）The application of N₂O₄ in the synthesis of a kind of cage polynitro compound-hexanitrohexaazaisowurtzitane（CL-20） was studied in this charpter. Firstly N₂O₄ was used to react with tetraacetyldibenzylhexaazaisowurtzitane（TADB） to synthesis its debenzylation product tetraacetyldinitrosohexaazaisowurtzitane（TADNSIW）, Firstly N₂O₄ was used to react with tetraacetyldibenzylhexaazaisowurtzitane（TADB） to synthesis its debenzylation product tetraacetyldinitrosohexaazaisowurtzitane（TADNSIW）, the optimized process was TADB（g）/ N₂O₄（ml）=2:3,reacting temp.65-70℃,acetic acid as reaction solvent,and the productivity was 77.0%。Then TADNSIW was nitrified into CL-20 with mixed acids. The optimized process was Nitric acid（ml）:TADNS（g）=7:1, Nitric acid（ml）:Vitriol=2:1,reaction temp. 80℃,reaction time=60min,the productivity was94.5%, and the purity of CL-20 was99.5%.