Theoretical Study On The Detonation Performances Of The High-nitrogen Heterocyclic Compounds

High-nitrogen heterocyclic compounds, with substantially enhancedperformance, reduced sensitivity, and manageable energy release, havebeen the focus in the field of advanced energetic materials for many years.Due to the time-consuming, expensive and dangerous factors in the testsof explosives, theoretical studies play a necessary and important role ininvestigating the relations between structures and properties and providefoundamental guidance for experiments.In this dissertation, formular structures of120compounds with twohigh-nitrogen heterocycles were designed base on furazan,1,2,4-oxadiazole and tetrazole, which were fully optimized atB3LYP/6-311G*level. Furthermore, the heats of formation of all thesecompounds with different substituents and linkages were calculated bydesigning isodesmic reactions, which throwed a light on the relationshipbetween the heat of formation and molecular structures. The resultsshowed that high-nitrogen heterocyclic compounds with the N3substituted group had the highest heats of formation among the NH2、-NO2、-ONO2、-NF2、-N3、-NHNO2、-NHNH2groups. With the samesubstituted groups, the nitrogen-bridged compounds(-NH-，-NH-NH-，-N=N-) had higher heats of formation than the carbon-bridgedcompouds(-CH2-，-CH2-CH2-，-CH=CH-). Compared with the adjointnitrogen-bridged and carbon-bridged compounds, the non-adjoint bridgedcompounds had lower heats of formation. Moreover, the nitrogen contentof the structure unit was higher; the higher was the heat of formation.The title compounds molar volume and theoretical density wereestimated using the Monte-Carlo method based on0.001e. bohr-3densityspace. Furthermore, the detonation velocity and pressure of thederivatives were estimated by the Kamlet-Jacbos equation. All theseresults layed quantitative basis for the HEDC design.In order to predict the detonation velocity of high-nitrogencompounds, the following calculated descriptors, Q, ρ and ΔE of54high-nitrogen compounds were calculated using DFT-B3LYP methodwith the6-31G**basis set, which were then used to build the linear and nonlinear multivariable models by multiple linear regression(MLR) andleast square support vector machine(LS-SVM) methods, respectively. Itturned out that the two models, whose stabilities were confirmed usingthe leave-one-out validation, were able to describe about95.5%and96.2%of the variance of the experimental values, respectively. Externalvalidation was carried out with R2extand Q2extvalues of0.921,0.911,0.971and0.955, respectively. Moreover, the results of theY-randomization test revealed that there were no chance correctionsamong the data matrix. Among the three molecular descriptors, the mostsignificant descriptor was the mass distribution ρ. The second significantdescriptor was Q. These results coupling theoretical calculations andQSPR methods can be complementary to experimental tests, providingguidance for the prediction of high-nitrogen compounds’ velocities.