Research And Effective Screening Methods Of Cocrystal Explosives

Cocrystal as a modification technology,it is a multi component molecular crystal with specific structure and property,which combines two or more than two molecules through the non covalent bonding force in the same lattice.And the force of the non covalent bond include the intermolecular hydrogen bond,?-? stacking and electrostatic interaction.There is no systematic screening method for the discovery of new cocrystal explosives,and there is also a lack of research on the process of cocrystal explosives formation.Therefore,this paper selected BTF and CL-20 explosives as the main body and used thermal analysis to screen them.This paper also investigated the formation process of cocrystal by NMR.Differential scanning calorimetry(DSC)is used as a primary screening method for cocrystal explosives.A large number of screening experiments on DNTF(3,4-bis(4'-nitrofurazano-3'-yl)furoxan),BTF(benzotrifuroxan)and CL-20(2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane)systems,and the objects that may form cocrystal with BTF and CL20 are obtained.The cocrystal of BTF/p-nitrobenzaldehyde was synthesized by solvent evaporation method,and obtained the crystal structure parameters of BTF/p-nitrobenzaldehyde cocrystal by single crystal XRD analysis,and calculated the detonation velocity and detonation pressure of cocrystal by the theoretical calculation of the LOTUSES code.The CL-20/trinitroresorcin cocrystal was obtained by spray drying which effectively improved the sensitivity of CL-20,and its sensitivity and detonation velocity were measured.The systematic screening and preparation of the cocrystal explosive by thermal analysis can provide guidance for the screening and preparation of the cocrystal explosives in the future.Taking TNT/CL-20 cocrystal explosive as the main body,the formation process of cocrystal is investigated by NMR.The hydrogen spectrum of TNT/CL-20 cocrystal was tested by 300MHz superconducting NMR instrument for four days.By analyzing the nuclear magnetic resonance spectrum,we can see that during the formation of TNT/CL20 cocrystal,hydrogen bonds on CH3 of TNT and oxygen on nitro group in CL-20 lead to hydrogen bonding effect,which leads a new peak appeared.With the increase of time,the formation of TNT/CL-20 cocrystal became more and more stable,and the chemical and integral area of the peak increased with the reaction time,and finally tended to be stable.In the formation of TNT/CL-20 cocrystal,the conclusion that obtained by NMR are consistent with the result that obtained from the analysis of the crystal cell structure.And NMR provided a new idea for the study of the cocrystal formation mechanism.