Theoretical study of solvent effects on RDX crystal quality and sensitivity using an implicit solvation model

Area of Science:

• Computational Chemistry
• Materials Science
• Chemical Engineering

Background:

• Cyclotrimethylenetrinitramine (RDX) is a high explosive with significant applications.
• Understanding solvent effects on RDX properties is crucial for safe handling and improved performance.
• Previous studies have explored RDX properties, but solvent-specific impacts require further elucidation.

Purpose of the Study:

• To investigate the influence of various solvents on the crystal quality and sensitivity of RDX using computational methods.
• To elucidate the molecular-level interactions between RDX and different solvent molecules.
• To predict the optimal solvents for RDX crystallization and sensitivity reduction.

Main Methods:

• Density functional theory (DFT) calculations employing the SMD solvation model.
• Analysis of molecular geometry, including bond lengths, angles, and dihedral angles.
• Natural Population Analysis (NPA) to assess charge distribution.
• Calculation of bond dissociation energies (BDE) and surface electrostatic potentials.

Main Results:

• Solvent interactions significantly alter the N-N bond length of RDX compared to the gas phase.
• Solvation effects lead to increased electron density on RDX oxygen atoms and positive charge on the molecular skeleton.
• Calculations indicate a potential reduction in RDX sensitivity due to solvent effects, with limitations.
• Predicted higher crystal quality for RDX crystallized from cyclohexanone and dimethyl sulfoxide.

Conclusions:

• Solvent choice critically influences RDX molecular structure, charge distribution, and sensitivity.
• Cyclohexanone and dimethyl sulfoxide are predicted to yield superior RDX crystal quality.
• The findings provide a theoretical basis for optimizing RDX processing and handling through solvent selection.