| The melt-cast explosive carrier is a low-melting component in melt-cast explosives,and its performance directly affects the application of melt-cast explosives,and melt-cast explosives occupies an important position in military mixture explosives.Therefore,the research and development of melt-cast explosive carriers with excellent performance are of great significance for improving the level of weapon equipment.1-Methyl-2,4,5-trinitroimidazole（MTNI）has excellent sensitivity and detonation properties,and has the potential to be used as melt-cast explosive carriers,however,according to the synthesis process of the existing literatures,the target compound could not be obtained or the yield was lower.Therefore,this thesis studies the synthesis and properties of MTNI and related intermediate products.The details are as follows:（1）To study the nitration reaction of imidazole,4（5）-nitroimidazole,2-nitroimidazole and2,4（5）-dinitroimidazole in fuming nitric acid and concentrated sulfuric acid（or 20%fuming sulfuric acid）;2,4,5-trinitroimidazole（in the form of its potassium salt）was synthesized,and using it as a raw material,2,4,5-trinitroimidazole 1,2,4-triazolium,2,4,5-trinitroimidazole 3-amino-1,2,4-triazolium,and 2,4,5-trinitroimidazole 4-amino-1,2,4-triazolium were prepared;study on methylation reaction of 2,4（5）-dinitroimidazole and 2,4,5-trinitroimidazole potassium salt with DMS to obtain 2,4-dinitro-1-methylimidazole,MTNI,1-methylimidazoline-2,4,5-trione and 1,3-dimethylimidazoline-2,4,5-trione;the structure of products were characterized;the thermal decomposition properties of three kinds 2,4,5-trinitroimidazole triazole salts were studied using DSC and ARC.The results showed that 4,5-dinitroimidazole was obtained from imidazole or 4（5）-nitroimidazole;2,4,5-trinitroimidazole and ethanedioic acid were obtained from 2-nitroimidazole or 2,4（5）-dinitroimidazole;methylation reaction of of 2,4（5）-dinitroimidazole and 2,4,5-trinitroimidazole potassium salt with DMS only generated the corresponding methylated products in the alkaline system;methylation reaction products of2,4（5）-dinitroimidazole with DMS were 2,4-dinitro-1-methylimidazole,1-methylimidazoline-2,4,5-trione and 1,3-dimethylimidazoline-2,4,5-trione in non-alkaline systems;methylation reaction between 2,4,5-trinitroimidazole potassium salt with DMS,the product was MTNI at80°C,and the products were 1-methylimidazoline-2,4,5-trione and 1,3-dimethylimidazoline-2,4,5-trione at 90°C in non-alkaline system;when the heating rate tends to zero under non-adiabatic conditions,the thermal decomposition peak temperatures of three kinds 2,4,5-trinitroimidazole triazole salts were 482.16 K,458.16 K and 459.45 K,respectively,indicating that they all had better thermal stability;the thermal decomposition reaction order of three kinds2,4,5-trinitroimidazole triazole salts were both n=2,and the most probable mechanism function of thermal decomposition reaction were both f（α）=（1-α）2 under adiabatic conditions.（2）Study on nitration reaction of N-methylimidazole,1-methyl-2-nitroimidazole,1-methyl-4-nitroimidazole,1-methyl-5-nitroimidazole,2,4-dinitro-1-methylimidazole,2,5-dinitro-1-methylimidazole and 4,5-dinitro-1-methylimidazole（4,5-MDNI）in fuming nitric acid and 20%fuming sulfuric acid to obtain 4,5-MDNI,MTNI and 1-methylimidazoline-2,4,5-trione;4,5-MDNI was synthesized using N-methylimidazole as raw materials,fuming nitric acid and concentrated sulfuric acid as nitrating reagents,and the process was optimized;the structure of products were characterized;the heat of formation of 4,5-MDNI was calculated using Gaussian software,detonation velocity and detonation pressure were further calculated,impact sensitivity and friction sensitivity were measured,and its thermal decomposition performance was studied using DSC and ARC.The results showed that when there was no nitro group at the C-2 position of imidazole ring,the main nitration product was 4,5-MDNI,and the highest yield of MTNI was only 2.5%;when a nitro group was attached to the C-2 position of imidazole ring,nitration at 80°C in V（fuming nitric acid）:V（20%fuming sulfuric acid）=1:3 for 2.5 h to obtain MTNI with yields of 65.0-82.3%;among them,the yield of MTNI was highest when 2,5-dinitro-1-methylimidazole was used as the raw material;the optimal process conditions for the synthesis of 4,5-MDNI were n（fuming nitric acid）:n（N-methylimidazole）=5:1,V（concentrated sulfuric acid）:V(fuming nitric acid)=4:1,reaction temperature was 120°C,reaction time was 2 h,and the yield was 41.3%;its detonation velocity,detonation pressure,impact sensitivity and friction sensitivity were 7429m·s-1,22.97 GPa,90 cm and 0%,respectively;the thermal decomposition peak temperature of4,5-MDNI was 539.35 K when the heating rate tends to zero under non-adiabatic conditions,indicating it had better thermal stability;the thermal decomposition reaction order of 4,5-MDNI was n=2,and the most probable mechanism function of thermal decomposition reaction was f（α）=（1-α）2 under adiabatic conditions.（3）Study on the nitration reaction of 2,4,5-triiodoimidazole in different concentrations of nitric acid to obtain 2,5（4）-diiodo-4（5）-nitroimidazole,2,4（5）-dinitro-5（4）-iodoimidazole,4,5-dinitro-2-iodoimidazole,2,4,5-trinitroimidazole（in the form of its imidazolium）and ethanedioic acid;the structure of products were characterized;Gaussian software was used to calculate the heat of formation,detonation velocity and detonation pressure were further calculated;impact sensitivity and friction sensitivity were measured.The results showed that during the nitration of 2,4,5-triiodoimidazole,ethanedioic acid was formed when dinitro products were present;detonation velocity,detonation pressure,impact sensitivity and friction sensitivity of the four products were 5381 m·s-1,16.64 Gpa,>150 cm,0%;6460 m·s-1,19.94Gpa,120 cm,0%;6141 m·s-1,17.32 Gpa,130 cm,0%;and 7923 m·s-1,25.58 Gpa,85 cm,0%,respectively.（4）Study on nitration reaction of 1-methyl-2,4,5-triiodoimidazole in different concentrations of nitric acid or a mixture of nitric acid and sulfuric acid to obtain MTII mononitrate,2,4-diiodo-1-methyl-5-nitroimidazole,2,5-diiodo-1-methyl-4-nitroimidazole,4,5-dinitro-2-iodo-1-methylimidazole,2,4-dinitro-5-iodo-1-methylimidazole,2,4-dinitro-1-methylimidazole,MTNI and 1-methylimidazoline-2,4,5-trione;the structure of products were characterized;Gaussian software was used to calculate the heat of formation,detonation velocity and detonation pressure were further calculated;impact sensitivity and friction sensitivity were measured;the thermal decomposition properties of MTNI was studied using DSC.The results showed that nitration conditions were V（fuming nitric acid）:V（20%fuming sulfuric acid）=2:1 or V（fuming nitric acid）:V（concentrated sulfuric acid）=1:3,reaction temperature was 90°C,reaction time was 2.5 h,nitration with 1-methyl-2,4,5-triiodoimidazole and its nitro derivatives as raw materials can obtain MTNI,and the highest yield was 41.5%;detonation velocity,detonation pressure,impact sensitivity and friction sensitivity of 2,4-diiodo-1-methyl-5-nitroimidazole,2,5-diiodo-1-methyl-4-nitroimidazole,4,5-dinitro-2-iodo-1-methylimidazole,2,4-dinitro-5-iodo-1-methylimidazole,2,4-dinitro-1-methylimidazole and MTNI were 4871 m·s-1,13.48Gpa,>150 cm,0%;4725 m·s-1,12.50 Gpa,>150 cm,0%;6878 m·s-1,24.26 Gpa,>150 cm,0%;6978 m·s-1,25.39 Gpa,>150 cm,0%;7244 m·s-1,21.75 Gpa,110 cm,0%;and 8768 m·s-1,33.74 Gpa,76cm,0%,respectively.The thermal decomposition peak temperature of MTNI was 550.66 K when the heating rate tends to zero under non-adiabatic conditions,indicating it had better thermal stability.（5）Using imidazole as raw material,through two-step nitration,thermal rearrangement,methylation,and renitration was the best process route for synthesizing MTNI,the total yield was 30.5%and the cost of raw materials were 312.28 RMB·kg-1. |
PDF Full Text Request