The Synthesis Technology Of1-methyl-2,4,5-trinitroimidazole

In the early days, polynitroimidazoles compounds were to be closely watched for theirexcellent medicinal properties. Reddy Damavaipu found they could be used as melt castexplosive carrier by their fine explosive performance. Most of polynitroimidazolescompounds have large π bond, which lead the fact that these compounds can be used as a kindof potential explosive with highly stable to thermal heating and substantially insensitive toimpact.1-methyl-2,4,5-nitroimidazole (MTNI) is a high energy (close to RDX), insensitive(close to B explosive) and low melting point explosive which belongs to polynitroimidazolesderivatives. Therefore, studying the synthesis process has a great significance.In this paper, two synthetic routes were designed:(1) direct nitration, using N-methylimidazole as raw materials and nitro-sulfuric acid as nitrating agent;(2)iodo-nitrification, using N-methylimidazole as raw materials via iodide oxidation system(I2/HIO3/CH3COOH), then nitrified it with super acid.Firstly，the synthetic process of direct nitration was explored according to the route (1).The synthetic product was characterized by IR,1H NMR, MS and analyzed the thermalstability which indicate that the final product merely get1-methyl-4,5-dinitroimidazole bydirect nitration. Meanwhile, the reaction mechanism of direct nitration was conjectured andthe feasibility of nitrifing1-methyl-4,5-dinitroimidazole was analyzed. The synthetic processof1-methyl-4,5-dinitroimidazole was optimized by single factor experiments and orthogonalexperiments, the optimal synthesis conditions were obtained: reaction temperature was120℃,reaction time was3h, the molar ratio of fuming sulfuric acid and fuming nitric acid was2.0:1.Secondly, the synthetic process of iodo-nitration was explored according to theroute (2).1-methyl-2,4,5-triiodoimidazole was synthesized by using N-methylimidazole as starting material via iodination and then1-methyl-2,4-dinitroimidazole and1-methyl-5-iodo-2,4-dinitroimidazole were got by nitration,1-methyl-2,4,5-nitroimidazolewas obtained by nitrifying1-methyl-5-iodo-2,4-dinitroimidazole. The synthetic intermediateand target product were characterized by IR,1H NMR, MS and analyzed the thermalstability. Meanwhile, the reaction mechanism iodization was conjectured and the complexityof nitrifing1-methyl-2,4-dinitroimidazole and1-methyl-5-iodo-2,4-dinitroimidazole werecompared. The synthetic process of1-methyl-2,4,5-triiodoimidazole was optimized by singlefactor and orthogonal experiments, the optimal synthesis conditions were obtained: themolar ratio of I2and N-methylimidazole was1.7:1, the molar ratio of HIO3andN-methylimidazole was1.8:1, the reaction time was2.5h. The synthetic process of1-methyl-2,4,5-trinitroimidazole was optimized by single factor and orthogonal experiments,the optimal synthesis conditions were obtained: reaction time was2.5h, reaction temperaturewas85℃, the molar ratio of KNO3and fuming sulphuric acid was1.2:1.Finally,1-methyl-2,4,5-nitroimidazole in different solvents were predicted by molecularmodeling software Materials Studio and the crystal morphology of which were compared withexperimental results in this paper, in order to guide the crystallization process of1-methyl-2,4,5-nitroimidazole in the future. The simulation provided a theoretical foundationfor selecting solvent in the crystallization of1-methyl-2,4,5-nitroimidazole.