Quantitative Study of the Decomposition of Dimethyl Methylphosphonate (DMMP) on Metal Oxides at Room Temperature and Above

Abstract

The adsorption and decomposition reactions of dimethyl methylphosphonate (DMMP) on a commercial γ-Al 2 O 3 , a γ-Al 2 O 3 -supported iron oxide, and a sol-gel-prepared alumina have been examined at temperatures from 25 to 400 °C. The capacities of these solids for the decomposition of DMMP have been measured, and the identities and amounts of the decomposition products determined over the entire temperature range. The alumina surfaces yield higher total amounts of decomposition products than the supported iron oxide material, with the sol-gel alumina showing very high activity. When corrected for surface area, however, the supported iron oxide material shows an activity equal to that of the γ-Al 2 O 3 support. The sol-gel alumina shows a higher activity at all temperatures up to saturation of the surface, presumably because of the presence of transitional phases that yield more reactive surface sites. At 25 °C, the commercial γ-Al 2 O 3 shows a total decomposition capacity of 117 µmol/g, the alumina-supported iron oxide material a capacity of 93 µmol/g, and the sol-gel alumina a capacity of 208 µmol/g. At 100 °C, these capacities increase by about a factor of 3, and at 200 °C and above, all of the materials show some capacity for sustained decomposition of DMMP.

Synthesis and characterization of porous WO 3 –SnO 2 nanomaterials: An infrared study of adsorbed pyridine and dimethyl methylphosphonate

“…The base line recovery for SMO sensors after the exposure to DMMP is very poor which limits its long time applicability. In an attempt to understand the reasoning behind this significant reduction in the sensors response, metal oxide nanopowders including WO 3 were fabricated in previous work [39,[58][59][60]. The surface behavior towards DMMP vapor was studied at various temperatures.…”

Removal of high concentration dimethyl methylphosphonate in the gas phase by repeated-batch reactions using TiO2

“…Several studies have been conducted in order to investigate the effects of temperature conditions on adsorption and decomposition of DMMP on TiO 2 surface [11][12][13][14][15][16]. Rusu and Yates [15] reported that at the temperature lower than −113 • C, DMMP condenses as an ice layer on the outer surface of TiO 2 .…”

“…Above −59 • C (from −59 • C to 213 • C), cleavage of P-OCH 3 groups takes place, with the production of Ti-OCH 3 species, and the dissociation of chemisorbed DMMP is seen. Sheinker and Mitchell [16] reported on the thermal decomposition of DMMP on ␥-Al 2 O 3 at temperatures from 25 • C to 400 • C and showed that the DMMP that is adsorbed is decomposed at 25 • C and increasing temperature brings about an increase in the decomposition activity of the surface. In our study, the temperature of the interior reactor was controlled as one of the optimization processes, in order to prevent DMMP adsorption as far as possible.…”

“…3 because the retention time of formaldehyde was not clear using GC analysis with FID detector. Sheinker and Mitchell [16] reported that dimethyl ether and methanol were produced as volatile products by thermal decomposition of DMMP with ␥-alumina at both 25 • C and 100 • C. Knagge et al [17] reported that thermal reaction of DMMP and O 2 on nanocrystalline NaY at 200 • C yielded several gas-phase products including dimethyl ether, formaldehyde, CO, CO 2 . Therefore, we assumed that unidentified Products 1 and 4 (or in reverse order) in Fig.…”

Decontamination of Yperite using mesoporous mixed metal oxide nanocrystals

“…Subsequently, the electronic environment on the surface also changes prompting surface chemistry to change. These intriguing properties along with chemical functionalities promote enhanced decontamination properties towards environmental contaminants [7][8][9][10][11].…”