Ambient Volatility of DMMP

Tevault, David E.; Buchanan, James H.; Buettner, Leonard C.

doi:10.1007/s10765-006-0044-3

Cited by 16 publications

(16 citation statements)

References 3 publications

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“…The ZnO nanoparticles were then cooled to room temperature in flowing O 2 . The DMMP exposure was performed using a saturator cell kept at 286 K with argon as the carrier gas. , A total flow rate of 30 mL min –1 was used with an estimated DMMP concentration of 75 ppm. A second test was performed by exposing both ZnO nanopowders to DMMP without any heat pretreatment to compare the differences in how DMMP adsorbs depending on the amount of water and carbonates initially adsorbed on the ZnO particles.…”

Section: Methodsmentioning

confidence: 99%

Adsorption and Destruction of the G-Series Nerve Agent Simulant Dimethyl Methylphosphonate on Zinc Oxide

et al. 2018

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Organophosphorus chemical warfare agents (CWAs) are extremely toxic compounds that are nominally mitigated with gas mask filtration employing metal oxide impregnated activated carbon filtration material. To develop more effective sorbents, it is important to understand the surface chemistry between these organophosphorus compounds and the individual components that make up these filtration materials. In this study, density functional theory (DFT) and Fourier transform infrared spectroscopy (FTIR) were employed to investigate the adsorption and decomposition mechanisms between a sarin simulant molecule, dimethyl methylphosphonate (DMMP), and zinc oxide, which is a component found in current filtration materials. Theoretical calculations show that DMMP readily adsorbs to a pristine and hydroxylated ZnO (101̅0) surface with average adsorption energies of 132 and 65 kJ mol–1, respectively. Experimental diffuse reflectance fourier transform infrared spectroscopy (DRIFTS) reveals that ZnO adsorbs water and readily hydroxylates under ambient conditions, which can facilitate adsorption through hydrogen bonding of the PO to ZnO surface hydroxyls. FTIR gas phase analysis also reveals that DMMP decomposes in the presence of ZnO nanoparticles (NPs) to produce methanol at room temperature. Assuming a fully hydroxylated surface of ZnO, DFT calculations reveal several plausible mechanisms for DMMP decomposition to form methanol with an activation energy barrier of 99.6 kJ mol–1. On the basis of this energy barrier to decompose DMMP, a turnover frequency (TOF) of only 3.5 × 10–7 s–1 is calculated assuming full coverage of DMMP on the ZnO nanoparticles tested. This value is qualitatively consistent with experimental results.

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Section: Methodsmentioning

confidence: 99%

Adsorption and Destruction of the G-Series Nerve Agent Simulant Dimethyl Methylphosphonate on Zinc Oxide

et al. 2018

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“…Before DMMP exposure, MoO 3 /KBr powder was loosely packed in an environmental DRIFTS cell and heated to 673 K in 20 mL/min of flowing O 2 for 2 h. This step was taken to ensure the mixture was dehydrated and fill oxygen vacancies on the surface of the MoO 3 nanoparticles. The mixture was then cooled to room temperature and the DMMP exposure was performed using a saturator cell, described elsewhere [10,11], with argon as the carrier gas. A flow rate of 20 mL/min was used with an estimated DMMP concentration of 90 ppm.…”

Section: Diffuse Reflectance Infrared Fourier Transform Spectroscopymentioning

confidence: 99%

Thermal desorption of dimethyl methylphosphonate from MoO₃

Head

Tang

Hicks

et al. 2017

Catalysis, Structure & Reactivity

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Organophosphonates are used as chemical warfare agents, pesticides, and corrosion inhibitors. New materials for the sorption, detection, and decomposition of these compounds are urgently needed. To facilitate materials and application innovation, a better understanding of the interactions between organophosphonates and surfaces is required. To this end, we have used diffuse reflectance infrared Fourier transform spectroscopy to investigate the adsorption geometry of dimethyl methylphosphonate (DMMP) on MoO 3 , a material used in chemical warfare agent filtration devices. We further applied ambient pressure X-ray photoelectron spectroscopy and temperature programmed desorption to study the adsorption and desorption of DMMP. While DMMP adsorbs intact on MoO 3 , desorption depends on coverage and partial pressure. At low coverages under UHV conditions, the intact adsorption is reversible. Decomposition occurs with higher coverages, as evidenced by PCH x and PO x decomposition products on the MoO 3 surface. Heating under mTorr partial pressures of DMMP results in product accumulation.

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“…Because the neurotoxic chemical warfare agents (CWAs) are included within the OP class of compounds, it is important to be able to understand and predict the impact of hydration on the chemical and physical properties of OPs. Examples of the influence of OP hydration include the observation of Henry's law deviations for the vapor pressure of Sarin (GB) over water [1], the acceleration of Sarin hydrolysis in humid environments, the pH and water quality dependence of Sarin hydrolysis [2], the moderate enhancement of Sarin photo-degradation with increasing relative humidity (RH) levels [3], and the reduction of volatility for the CWA simulant dimethyl methylphosphonate (DMMP) with increasing relative humidity (RH) [4]. Water is also known to directly impact the breakthrough, degradation and adsorption energies of OPs on a variety of different surfaces [5][6][7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Infrared signature of micro-hydration in the organophosphate Sarin: an ab initio study

Alam

Pearce

2015

J Mol Model

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The infrared (IR) spectra of micro-hydrated Sarin•(H2O)n clusters containing between one and four explicit waters have been studied using ab initio density functional theory (DFT) methods. The phosphate group P=O bond vibration region (∼1270 to 1290 cm(-1)) revealed the largest frequency variation with hydration, with a frequency red shift reflecting the direct hydrogen bond formation between the P=O of Sarin and water. Small variations to the P-F stretch (∼810 to 815 cm(-1)) and the C-O-P vibrational modes (∼995 to 1004 cm(-1)) showed that the water interactions with these functional groups were minor, and that the structures of Sarin were not extensively perturbed in the hydrated complexes. Increasing the number of explicit hydration waters produced only small vibrational changes in the lowest free energy complexes. These minor changes were consistent with a single water-phosphate hydrogen bond being the dominant structure, though a second water-phosphate hydrogen bond was observed in some complexes and was identified by an additional red shift of the P=O bond vibration. The H2O•H2O vibrational modes (∼3450 to 3660 cm(-1)) increased in complexity with higher hydration levels and reflect the extended hydrogen bonding networks formed between the explicit waters in the hydrated Sarin clusters. Graphical Abstract Ab initio studies of the infrared signature for micro-hydrated Sarin.

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Ambient Volatility of DMMP

Cited by 16 publications

References 3 publications

Adsorption and Destruction of the G-Series Nerve Agent Simulant Dimethyl Methylphosphonate on Zinc Oxide

Adsorption and Destruction of the G-Series Nerve Agent Simulant Dimethyl Methylphosphonate on Zinc Oxide

Thermal desorption of dimethyl methylphosphonate from MoO₃

Infrared signature of micro-hydration in the organophosphate Sarin: an ab initio study

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Ambient Volatility of DMMP

Cited by 16 publications

References 3 publications

Adsorption and Destruction of the G-Series Nerve Agent Simulant Dimethyl Methylphosphonate on Zinc Oxide

Adsorption and Destruction of the G-Series Nerve Agent Simulant Dimethyl Methylphosphonate on Zinc Oxide

Thermal desorption of dimethyl methylphosphonate from MoO3

Infrared signature of micro-hydration in the organophosphate Sarin: an ab initio study

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Thermal desorption of dimethyl methylphosphonate from MoO₃