Base Hydrolysis of HMX and HMX-Based Plastic-Bonded Explosives with Sodium Hydroxide between 100 and 155 °C

Abstract

The degradation of HMX-based high explosives (HMX, PBX 9404, and PBX 9501) with sodium hydroxide solutions is described. To obtain practicable reaction rates, the reaction was carried out in a pressurized reactor at temperatures up to about 155 °C. Above about 70 °C, mass transfer rates significantly affect the observed reaction rate. Therefore, a solid−liquid mass transfer model, based on gas−liquid film theory, was developed to describe the reaction rate. This model successfully predicted the experimentally observed degradation of explosives. Similar work with sodium carbonate solutions was reported previously. Faster reaction rates were observed with sodium hydroxide, a stronger base. Sodium hydroxide is preferred when the explosive contains a base-resistant binder, such as the binder used in PBX 9501, or when large, pressed pieces of explosives are used. Sodium carbonate hydrolysis and sodium hydroxide hydrolysis yielded the same degradation products.

Alkaline Hydrolysis of the Cyclic Nitramine Explosives RDX, HMX, and CL-20: New Insights into Degradation Pathways Obtained by the Observation of Novel Intermediates

“…Hoffsommer and co-workers (16) reported that RDX degradation in alkaline medium was initiated by a single denitration step to first form pentahydro-3,5-dinitro-1,3,5-triazacyclohex-1-ene (II), which then hydrolyzed further leading to rapid ring cleavage and decomposition. While only a few studies have been conducted with HMX, it has been shown that HMX undergoes alkaline hydrolysis at a slower rate than RDX (17,18), to give a product distribution (NO2 -, N2O, NH3, N2, and HCOOH) similar to that obtained with RDX (19). The polycyclic nitramine 2,4,6,8,-10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL- 20) has only recently been synthesized (20,21).…”

“…Therefore, if other cyclic nitramines such as MNX (hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine), HMX, and CL-20 produce end products similar to those of RDX, then their decomposition mechanisms should also be similar (18,19). Hence, our objective in the present study was to provide additional insight into the degradation pathways of these cyclic nitramines by first determining whether RDX, HMX, MNX, and CL-20 hydrolyzed in aqueous, alkaline (pH 10) conditions to produce similar end products.…”

Soils contaminated with explosives: Environmental fate and evaluation of state-of-the-art remediation processes (IUPAC Technical Report)

“…4,6-Dinitro-2,4,6-triazahexanal and 5-hydroxy-4-nitro-2,4-diaza-pentanal were identified as by-products leading to the formation of the ring cleavage product 4-nitro-2,4-diazabutanal. The efficacy of alkaline hydrolysis may be enhanced with an increase in reaction temperature [51][52][53][54], however, thermal runaway may occur at temperatures greater then 120 °C [53].…”

Aqueous solubility and alkaline hydrolysis of the novel high explosive hexanitrohexaazaisowurtzitane (CL-20)

“…The by-products resulting from the alkaline hydrolysis of energetic materials could possibly be disposed of directly [8] or can be further treated biologically [10]. Several researchers have investigated the kinetics of the alkaline hydrolysis of nitrated energetic compounds such as RDX, HMX, TNT and nitrocellulose [11][12][13][14][15][16][17]. To date there have been no studies on the kinetics of the alkaline hydrolysis of CL-20.…”