Preparation, crystal structure and characterization of 2,4,6-trinitro-3,5- dimethylbenzoic acid monohydrate

In the present work, we synthesized 2,4,6-trinitro-3,5-dimethylbenzoic acid (TNDMBA). Single crystal of TNDMBA · H₂O was cultured from aqueous solution using a slow evaporation method at 30°C. The crystal structure was determined by X-ray single-crystal diffraction analysis. The crystal belongs to the monoclinic system with space group P2(1)/c having unit cell parameters of a = 17.24(3) Å, b = 6.032(1) Å, and c = 16.359(4) Å. There are two kinds of intermolecular H-bond interactions between H₂O and TNDMBA, which is different from typical carboxylic acids that form H-bond dimers across crystallographic centers of inversion. The title compound was characterized by FT-IR, DSC, and TG-DTG technologies, and calculated by using density functional theory (DFT) method. The calculated results show that the structural parameters from the theory are close to those of the crystal structure from the experiments. The compound is composed of three nitro groups and one carboxyl group, and it can be used as a potential energetic combustion catalyst in industry.