Research On Organic Amine Nitrate And The Formation Process/The Kinetics Of CL-20 Cocrystal

When two or more neutral species are combined via intermolecular interaction to form a new crystal structure,cocrystals are created with distinct physicochemical properties.Previous studies have shown that Explosive properties such as detonation speed and sensitivity can be improved by forming cocrystal explosives.The possibility of eutectic formation of organic amine nitrate was explored.The process of cocrystal formation was tracked by NMR,IR and DSC.The crystallization process of Cl-20(hexanitrohexazohetero-woods)/DNI(1,4-dinitroimidazole)eutectic explosive was studied by molecular dynamics.Its main content has the following several parts:Ethylenediamine dinitrate(YN)and triethylenediamine dinitrate(SN)and diethylenediamine trinitrate(EN)were the main research object,the preparation method,single crystal and cocrystal culture methods were studied.The improved preparation method has the following advantages: simple operation and easy separation,one-step production,high product yield and quality,mild reaction process with recycled mother liquor.However,its single crystal couldn’t be obtained thus no more information could be provided at the molecular level.Nevethelss,The reasons for the failure of cocrystal culture were analyzed from the aspects of intermolecular force and molecular structure.The formation process of TNT(1,3,5-trinitrotoluene)/ CL-20 cocrystal system in the liquid phase was tracked by liquid NMR and infrared spectroscopy,and the formation process of CL-20 series in the solid phase was tracked by differential scanning calorimetry(DSC).The experimental results of liquid NMR and IR spectrum tracing show that the liquid phase tracing characterization in the crystallization process cannot provide effective changes,and the liquid NMR and IR spectra are not feasible for tracking characterization methods.By DSC test method,we successfully screened and prepared a CL-20 series cocrystal explosive: CL-20 / trinitrolysophenol.Further DSC tracking tests of CL-20 /TNT,CL-20 /CPL(caprolactam)and CL-20 /DNB(m-dinitrobenzene)systems showed that not all cocrystal systems could be screened by DSC,and the selection of a lower heating rate was conducive to the observation of the characteristic peaks of cocrystal formation.The crystallization behavior of CL-20 /DNI cocrystal in DMSO(dimethyl sulfoxide)ethanol acetone solution at different temperatures was studied by molecular dynamics,It is known that the nucleation of CL-20 /DNI cocrystal occurs mainly in 6-12 ns,and the growth of 12-30 ns.During the nucleation and growth of CL-20 /DNI cocrystal,intermolecular forces mainly come from the hydrogen bonding between the hydrogen atom of CL-20 molecule and the oxygen atom of DNI molecule.In the crystallization process,no hydrogen bond was observed between oxygen atom of CL-20 molecule and hydrogen atom of DNI molecule.CL-20 /DNI cocrystal crystals are more suitable for nucleation and growth in ethanol acetone solvent,but not in DMSO solution for crystallization.Based on the study of binding energy and diffusion behavior of hydrogen bond radial distribution function,it was found that CL-20 /DNI cocrystal was more suitable for crystallization at 328 K,and the free CL-20 and DNI in solution decreased,and the diffusion coefficient showed a downward trend.