Molecular Design And Theoretical Studies On New High Energetic Compounds Containing Fluorine

High energetic compounds containing fluorine is an important kind of explosives and it is significantive to study their structures and performance.Theoretical methods such as desity functional theory have been used to study some fluorine-containing deriviatives of classical CHON energetic compounds.The structures,physicochemical properties,detonation performance,and stabilities have been systematically investigated to search for the relationships between structures and properties.Some compounds with better performance have been screened for further experimental studies.The main contents are as following:1.Four pentafluorosulfanyl deriviatives(PPTN,PDPDN,PTPN and TPNT)of pentaerythritol tetranitrate(PETN)were studied.Their molecular geometries were optimized and vibrational analyses were performed.The densities,thermodynamic functions,and detonation performance were estimated.The bond dissociation energy(EBDE)of the possible trigger bond corrected by basis set superposition error(BSSE)was also predicted.The results show that in comparison with PETN,PDPDN,PTPN,and TPNT,PPTN has the highest density and best detonation performance among five compounds.With the increase in the number of the pentafluorosulfanyl group,bigger densities show.But too many pentafluorosulfanyl groups lead to poor detonation properties.2.Some fluorine-containing deriviatives of nitrogen heterocycle compound 1,3,4,6-tetraaminooctahydrocyclobuta[1,2-d:3,4-d']diimidazole-2,5-dione were studied.Their structures,densities,detonation performance,and stabilities have been calculated and we found that the difluoramino group increases the density and detonation performance much more significantly than the nitro and nitrate groups do.The nitrate group can reduce the thermal stability and too many fluorine atoms will lead to poor detonation properties.3.Some difluoramino and nitrate deriviatives of DPO(2,5-dipicryl-1,3,4-oxadiazole)have been designed and the relationships between structures and properties have also been studied.It was found that difluoramino and nitrate groups can obviously increase the density and detonation performance.But the nitrate group may reduce the thermal stability.4.Some difluoramino deriviatives of 1,4-dihydro-1,2,4,5-tetrazine were designed and their molecular geometries,densities,thermodynamic functions,and detonation performance were studied.Once again,as was found in DPO deriviatives,the difluoramino group increases the densitiy and detonation performance more significantly than nitrate group.