Temperature- switchable ammonium acetate/diethylene glycol deep eutectic solvent for selective and green separation of cyclotetramethylenetetranitramine (HMX) and cyclotrimethylenetrinitramine (RDX) explosives

ABSTRACT

A green and low-cost deep eutectic solvent (DES) composed of ammonium acetate and diethylene glycol (DEG) was developed for selective separation of two similar structures cyclotetramethylenetetranitramine (HMX) and cyclotrimethylenetrinitramine (RDX) explosives. The influence of DES on the solubility of two explosives was statistically investigated by central composite design (CCD) of experiment, and some solubility parameters including activity coefficient, dissolving enthalpy, and mixing enthalpy for RDX and HMX were determined. Empirical findings indicated that the dissolution ratio of RDX to HMX in DES varied between 10.0 and 30.0 times. This enables the development of a specific and successive leaching approach for green and selective extraction of two explosives produced in Bachmann nitration process with separation efficiency of greater than 98.1% and purity of HMX greater than 99.5%. Additionally, interactions of DES components and quality of products were evaluated using Fourier transform infrared spectroscopy (FT-IR), dielectric constants measuring over 100.0 Hz − 1.0 MHz, X-ray diffraction (XRD), high-performance liquid chromatography (HPLC), and laser-induced breakdown spectroscopy (LIBS). The suggested approach allows the preparation of pure RDX and HMX explosives in an effective, safe, and environmentally friendly manner, for using in oil well perforation.

GRAPHICAL ABSTRACT

KEYWORDS:

• Deep eutectic solvent
• HMX and RDX
• explosive
• separation
• solubility

Novelty statement

The novelty of this research can be summarized as follows:

• Development of an inexpensive deep eutectic solvents based on ammonium acetate/diethylene glycol.

• A selective solid-liquid separation of two similar structures RDX and HMX explosives in DES.

• Dielectric constant of DES were estimated using LCR meter.

• The solubility ratio of RDX/HMX in DES is 10-30 times, with separation efficiency >98.0%.

• Solubility parameters of HMX and RDX in DES were modeled and calculated.

• The presence of impurities was controlled using LIBS, XRD, FT-IR, and HPLC methods.

Acknowledgements

The authors are grateful for the financial support of this work by Malek-ashtar University of Technology (I.R. Iran).

Disclosure statement

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: This reports was provided by Malek Ashtar University of Technology – Shahin Shahr Campus. We reports a relationship with Malek Ashtar University of Technology – Shahin Shahr Campus that includes: board membership.