Theoretical insight on effect of DMSO-acetonitrile co-solvent on the formation of CL-20/HMX cocrystal explosive

Theoretical study of potential energetic material CL-20/DNAN eutectic explosive based on molecular dynamics method

CONTEXT

The exploration of CL-20 eutectic has been a subject of fervent interest within the realm of high-energy material modification. Through the utilization of density functional and molecular dynamics methods, an investigation into the characteristics of hexanitrohexaazaisowurtzitane (CL-20)/2,4-dinitroanisole (DNAN) within the molar ratio range of 9:1-1:9 was conducted. This inquiry encompassed the scrutiny of molecular interaction pathway, attachment force, initiating molecular distance, unified energy concentration, and physical characteristics. Furthermore, EXPLO-5 was harnessed to prognosticate the explosion features and byproducts of unadulterated CL-20, DNAN, and CL-20/DNAN frameworks. The findings delineate a substantial differentiation in the electrostatic charge distribution on the surface between CL-20 and DNAN particles, signifying the preeminence of intermolecular interactions between disparate entities over those within similar entities, thus intimating the plausibility of eutectic constitution. Remarkably, the identification of maximal attachment force at a molar ratio of 4:6 suggests the heightened likelihood of eutectic formation, propelled primarily by electrostatic and van der Waals forces. The resultant eutectic explosive evinces intermediate reactivity and exemplary mechanical attributes. Moreover, the detonation achievement of the eutectic with a molar proportion of 4:6 straddles that of CL-20 and DNAN, representing a new type of insensitive high-energy material.

METHODS

The testing method employs the Materials Studio software and utilizes the molecular dynamics (MD) method to predict the properties of CL-20/DNAN co-crystals with different ratios and crystal faces. The MD simulation time step is set to 1 fs, and the total MD simulation time is 2 ns. An isothermal-isobaric (NPT) ensemble is used for the 2-ns MD simulation. The COMPASS force field is employed, with the temperature set to 295 K. The prediction of detonation characteristics and products is conducted using the EXPLO-5 software.

Theoretical investigations on CL-20/ANTA co-crystal explosive via molecular dynamics method

CONTEXT

The study of CL-20 co-crystal has always been a focal point within the field of energetic material modification. In this study, we employed a combination of density functional theory and molecular dynamics simulations to investigate the properties of hexanitrohexaazaisowurtzitane (CL-20)/3-amino-5-nitro-1,2,4-triazole (ANTA) with different molar ratios ranging from 4:1 to 1:4. Additionally, EXPLO-5 software utilized to predict the detonation properties and products of pure CL-20, ANTA, and CL-20/ANTA systems. The results revealed that there was an interaction between CL-20 and ANTA molecules, which had the potential to form a co-crystal. The most likely molar ratio for co-crystal formation was 1:1, and the main driving forces for co-crystal formation were electrostatic force, dispersion force, and van der Waals force. The co-crystal explosive exhibited moderate sensitivity and excellent mechanical properties. Furthermore, the co-crystal detonation performance at a molar ratio of 1:1 was between that of CL-20 and ANTA, representing a new type of insensitive high-energy material.

METHODS

The properties of CL-20/ANTA co-crystal were predicted by molecular dynamics (MD) method under Materials Studio software. For the whole MD simulations, set the temperature at 298 K, and the pressure was 0.0001 GPa. Conducted MD simulation under the NPT ensemble for a total simulation duration of 1 ns. The first 0.5 ns was used for thermodynamic equilibrium, and the last 0.5 ns was used for statistical calculation and analysis. Sampling was recorded every 10 fs during the calculation.

Isomerization energies and surface electrostatic potential analyses on nitriles and isocyanides

Isocyanide-nitrile rearrangement has long been a continuing and interesting topic. A series of nitriles and isocyanides with the substituents of R = -AlH₂, -BeH, -BH₂, -C≡CH, -CF₃, -CH₃, -Cl, -C≡N, -COOH, -F, -H, Li, -MgH, -Na, -NH₂, -NO₂, -OH, -PH₂, -SH, -SiH₃, and -CH = CH₂ were investigated systematically based on full optimization at B3LYP-D3(BJ)/def2-QZVP level, and the isomerization energies from R-C≡N to:C = N-R were estimated. The substituent effect and bonding characters were analyzed by surface ESP colored van der Waals surfaces in conjunction with the global and local electrostatic extrema.