Study On The Preparation Of 1,1’-dihydroxy-5,5’-bitetrazole And The Thermal Decomposition Of Its Energetic Ion Compounds

Bitetrazoles receives concern with high formation enthalpy, high nitrogen content, high volume and characteristics of detonation products clean, in the energetic material research field. 1,1’-Dihydroxy-5,5’-Bitetrazole (1,1’-BTO) was obtained by 5,5’-bitetrazole with the introduction of hydroxyl group, which makes it show acidity.1,1’-BTO can synthesize ion salts with metal cation or nitrogen cation and will provide more choice of solid propellant and the burning catalyst. A new catalyst was added to improve the synthesis process. This study also focused on the mechanism of cyclization reaction. To find the potential energetic compounds, the thermal decomposition characteristics of ions salts are systematically studied.The process conditions were optimized:in the reaction of HCl gas in solvent, HCl ventilation time for 1.0h, reaction temperature at 25℃, the reaction time for 9h,the production rate is 61.2%. The energy of the transition state was calculated to study the cyclization reaction mechanism. In the same condition of the original reaction system, with ethyl acetate as solvent, concentration of HCl solution as the catalyst, tetrabutyl ammonium bromide (TBAB) as phase transfer catalyst, the reaction yield tall 82.5%. Meanwhile, the reaction time was shorten by 9h to 5h and there is no need for low temperature and ventilation device. Reaction process are simplified, which is beneficial to enlarge industrialization.1,1’-Dihydroxy-5,5’-Bitetrazole cobalt salt(1,1’-BTOCo), copper salt (1,1-BTOCu) and lead salt (1,1-BTOPb) were synthesized and the thermal decomposition processes were studied by differential scanning calorimetry (DSC) and thermogravimetry (TG). The apparent activation energy (EK and )and pre-exponential factor (AK) were calculated by Kissinger’s and Ozawa’s method, respectively. The thermal decomposition kinetic parameters and mechanism functions were presented. Results are as follows:for 1,1’-BTOCo, TSADT=534.46K, Tbpo=542.22K; for 1,1’-BTOCu, TSADT=527.56K, Tbpo= 539.11K; for 1.1’-BTOPb,TSADT=525.87K, Tbpo=580.00K. This shows the thermal stability of three salts, especially at room temperature.1,1’-BTO nonmetallic ion salts were synthesized with aqueous ammonia, hydroxylamine hydrochloride and 5-amino-tetrazole and the thermal decomposition processes were studied by DSC. Analysising with the results of quantum chemistry calculation, results show that by syntheticing ions salts, the thermal stability of the 1,1’-BTO performance are improved.