Safe recovery and cyclic use of dimethyl sulfoxide from HMX-contaminated solutions via wiped film evaporator/distillation coupled technology

Dimethyl sulfoxide (DMSO), a key solvent for Octogen (HMX) recrystallization, faces challenges in safe recovery and cyclic use due to thermal instability. This study has developed a Wiped Film Evaporator/Distillation coupled (WFE) technology to achieve efficient DMSO recovery from HMX-contaminated solutions. Compared to the conventional vacuum distillation, this technique could significantly increase the effective recycle time of DMSO. Optimal parameters (115°C jacket temperature, 0.005 MPa operational pressure, 6 mL/min feeding speed) were determined via Response Surface Methodology (RSM), yielding > 95.5 wt% DMSO purity with < 0.03 wt% decomposition. The method enabled at least 21 reuse cycles without compromising HMX recrystallization quality ( β -crystal structure confirmed by X-ray powder diffraction (XRD), defect-free morphology via Scanning Electron Microscopy (SEM)). The safety of the recovery process can be achieved through lower jacket temperatures. Thermal analysis (Accelerating Rate Calorimeter (ARC)/ Gas Chromatography Mass Spectrometry (GC-MS)) validated that no significant decomposition of DMSO and HMX was present at the jacket temperature of 115°C. This improvement is attributed to the lower pressure drop and higher heat transfer efficiency of the wiped film evaporator relative to conventional reboiler. This work provides a sustainable strategy for solvent recycling in energetic material industries, balancing efficiency, safety, and cost-effectiveness.