Synthesis and Research on Thermal Properties of One Kind of Heat Resistant Picryl Chloride Derivtive
|School||Nanjing University of Technology and Engineering|
|Keywords||hexanitrohydrazobenzene nitration nucleophilic substitution oxidation thermal analysis|
The final product hexanitrohydrazobenzene (HNAB) was synthesized by oxidation the intermediate 1,2-bis(2,4,6-trinitrophenyl)hydrazine which was prepared from 4-nitrochloro-benzene by two-step nitration and nucleophilic substitution reaction by different oxidants. In order to obtain the optimal technological conditions, the principal effect of each reaction was studied based on reaction mechanism. The thermal decomposition process of HNAB was studied by TG curves at different heating rates and activation energy was calculated. The structure and performance of HNAB coated with TNT was characterized by SEM, TG and size distribulation.The optimal synthetic processes as fallows:the first-step nitration conditions were that 4-nitrochlorobenzene 8g, sulphoacid 20mL, nitric acid fuming10.5mL, reation time 2h under 85℃, the yield was 87.5%. The second-step nitration conditions were obtained as follows: 2,4-dinitrochlorobenzene 5g, sulfuric acid fuming 26.7mL, potassium nitrate 11.83g, reation time 5h under 140℃, the yield was 94.5%. The nucleophilic substitution reaction conditions were obtained as follows:hydrazine sulfate 2g,2,4,6-trinitrochlorobenzene 7.61 g, methyl alcohol 15mL, triethylamine 6mL, reation time 24h under 45℃, the yield was 80.2%. The conditions of using nitric acid fuming as oxidants were obtained as follows:1,2-bis(2,4,6-trinitrophenyl)hydrazine 2g, nitric acid fuming 15mL, reation time 6h under 55℃, the yield was 85.4%. The conditions of using Iron(III) nitrate nonahydrate as oxidants were obtained as follows:1,2-bis(2,4,6-trinitrophenyl)hydrazine 2g, Iron(III) nitrate nonahydrate 7.12g, grind-ing to yellow, the yield was 84.4%. The conditions of using fenton reagent as oxidants were obtained as follows:1,2-bis(2,4,6-trinitrophenyl)hydrazine 2g, ferrous nitrate 3.9g,30% hydrogen peroxide 5mL, water lOmL, reation time 1h under 40℃, the yield was 81.4%. The product was characterized by MS, IR and 1HNMR.The thermal decomposition kinetics parameters of HNAB which was studied by TG curves at different heating rates were obtained by the Ozawa’s method. The results show that it was classified as random nucleation and growth of n=1. The mechanism function of the thermal decomposition process of hexanitrohydrazobenzene explosive is f(a)=(1-a). The thermal decomposition kinetic equation for HNAB was that:The test results of the mixture HNAB/TNT shown that:the size was increased and specific surface area was decreased of HNAB coated with 8% TNT compared with that of 2% TNT and 5% TNT(w.t), and particles was irregular. The thermal decomposition was effected by TNT decomposition temperstion. So, the modification effect after coated with 8% TNT is the most significant.