Synthesis And Properties Of 3,5-Dinitro-1,2,4-Triazole Metal Salts

3,5-dinitro-1,2,4-triazole（DNT）,as one of the energy-containing compounds of the triazole class,has a theoretical calculated density of 1.83 g·cm^-3,a burst velocity of 8.26km·s^-1and a burst pressure of 30.56 GPa,with a high density and excellent burst performance,but its own susceptibility and acidity limit its practical application.The results of domestic and international research have shown that energy-containing metal ion salts can improve thermal properties and reduce mechanical sensitivity to a certain extent,so this problem can be solved by trying to synthesise new metal ion salts with DNT as the parent by introducing different metal ions into the appropriate positions of DNT.This paper is centred on the synthesis and properties of 3,5-dinitro-1,2,4-triazole metal salts as follows:（1）Gaussian 09W software was used to optimize the geometric structure and calculate the frequency of DNT metal salts at the level of B3LYP/6-311G and B3LYP/Lan L2MB basis groups based on density generalization theory,and to obtain the bond lengths,bond levels,surface electrostatic potential distribution and electrostatic potential parameters for different molecular structures;the theoretical densities of DNT metal salts were combined with some electrostatic potential parameters calculations were carried out,and the results were2.163-3.480 g·cm^-3;the theoretical solid phase generation enthalpies of ionic compounds were calculated by designing reasonable isobonding reactions;their theoretical burst parameters were obtained by using the EXPLO 5 program,and the results showed that:DNT metal salt burst velocity range of 8079.04-9689.14 m·s^-1,burst pressure range of 27.23-58.54 GPa.（2）The intermediate 3,5-dinitro-1,2,4-triazole sodium salt（Na DNT）was synthesized by diazotization and substitution reaction using 3,5-diamino-1,2,4-triazole（DAT）as raw material;then the target products 3,5-dinitro-1,2,4-triazole lead salt（Pb DNT,yield 24.9%）,3,5-dinitro-1,2,4-triazole copper salt（Cu DNT,yield 31.4%）and 3,5-dinitro-1,2,4-triazole cuprous salt（Cu^ⅠDNT,yield 47.3%）were synthesized by metathetical reaction using Na DNT as raw material and lead nitrate,copper nitrate trihydrate and cuprous chloride,respectively.and to investigate the reaction mechanism of the DNT metal salts.The synthesized products were verified by melting point test,nuclear magnetic resonance（NMR）,infrared spectroscopy（IR）,X-ray photoelectron spectroscopy（XPS）and other characterization tests,and the results were consistent with the target products.The cultivated Na DNT single crystal was analyzed by single crystal diffractometer,and the results showed that the crystal structure was monoclinic crystal system,belonging to C2/c space group,with a cell density of 1.782g·cm^-3。（3）The thermal stability of the DNT metal salts was analysed using a thermal analyser with a TG-DTA coupling method;the thermal decomposition curves were then obtained for heating rates of 5,10,15 and 20℃·min^-1,and the kinetics of the non-isothermal thermal decomposition were investigated by substituting the measured peak temperatures of the thermal decomposition at different heating rates into the The corresponding kinetic equations were used to obtain a series of kinetic parameters for the DNT metal salts,specifically the reaction activation energy,the prefactor,the number of reaction steps,etc.The results showed that among the four different metal salts,the decomposition temperature of Na DNT was the highest,and the activation energy and pre-exponential factor were the highest,that is,the thermal stability was the best.In accordance with GJB 5891.22-2006,GJB 5891.24-2006 and GJB 772A-97,the mechanical sensitivity of DNT metal salts was tested and the results showed that,except for the characteristic fall height(H₅₀)of Cu^ⅠDNT of 100cm,the rest of the compounds did not ignite;the probability of explosion of frictional susceptibility was 8%,0%,4%and 56%respectively,which indicates that Cu^ⅠDNT is more sensitive compared with other metal salts.（4）The actual density of DNT metal salt is tested by the true density tester.Substitute the measured density and enthalpy of solid phase formation into EXPLO 5 program to get the optimized detonation parameters.Compare the performance of DNT metal salts with some conventional explosives.The data results show that the target products can effectively improve the detonation performance,mechanical sensitivity and acid deficiencies of their parent products,and are high energy passive-sensitive energetic compounds with good thermal properties.（5）Na DNT was selected for the study and the process conditions were optimised to investigate the effects of reaction temperature,reaction time,feeding ratio and solvent type on the yield of Na DNT,respectively.The results showed that the optimum reaction conditions for Na DNT were:diazotization reaction temperature of-8℃,nitration reaction temperature of60℃,reaction time of 1 h,n（DAT）:n（Na NO₂）=1:4,extraction solvent of acetone,and the yield of 65.1%.