ChemInform Abstract: Oxidative Detoxification of Phosphonothiolates.

Yang, Yu-Chu; Szafraniec, Linda L.; Beaudry, William T.; Rohrbaugh, D. K.

doi:10.1002/chin.199051232

Cited by 8 publications

(28 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A group contribution method 31 was used to compute the molar volume of VX, V̅ VX = 265 cm 3 /mol (see Supporting Information for details), yielding δ VX = 17.1 MPa 0.5 . To obtain a more accurate value for the Hildebrand solubility parameter for the particular silicone used here, eq 10 was used with the experimentally determined interaction parameters of water and methanol presented in Table 1.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Decontamination of chemical warfare agents (CWAs, or "agent") in the liquid phase where the agent is directly accessible by the decontaminant in solution has been wellstudied. 1,2 For example, several methods have been investigated to decontaminate the persistent nerve agent [2-(diisopropylamino)ethyl]-O-ethyl methylphosphonothioate (VX) including oxidative chemistries, 3,4 perhydrolysis, 5,6 vaporized hydrogen peroxide, 7 and household cleaners. 8 These studies have primarily considered liquid-phase reaction rate and byproduct composition as the key performance metrics for decontaminants.…”

Section: ■ Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Decontamination of VX from Silicone: Characterization of Multicomponent Diffusion Effects

Varady¹,

Pearl²,

Stevenson

et al. 2016

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

A continuum model of the transport and reaction processes occurring during decontamination of the chemical warfare agent (CWA) [2-(diisopropylamino)ethyl]-O-ethyl methylphosphonothioate (VX) absorbed in a silicone elastomer using solutions of sodium hydroxide in water, methanol, and mixtures thereof is presented. This model is based on the Maxwell-Stefan formulation of multicomponent diffusion along with the Flory-Huggins model of thermodynamic equilibrium in the polymer. It was found that, as methanol from the decontaminant absorbs into the silicone, the diffusivity of VX increases, accelerating its flux from the polymer phase to the decontaminant liquid phase. This composition dependence of the diffusivity was accurately described by the Vignes equation. Although the decontamination kinetics were slower for the methanol-based decontaminant in a well-stirred liquid-phase reactor, the overall performance was superior compared to the aqueous-based decontaminant due to the enhanced extraction rate from the polymer. These findings highlight the need to consider extraction dynamics on equal footing with reaction kinetics when formulating decontaminants intended for use on absorbing polymer materials.

show abstract

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Decontamination of VX from Silicone: Characterization of Multicomponent Diffusion Effects

Varady¹,

Pearl²,

Stevenson

et al. 2016

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

show abstract

“…Regarding the first point, previous studies have established that thiophosphonates (such as 4, the "head" part of 2) undergo oxidation to the corresponding sulfonium ion intermediate, which in turn serves as a good leaving group for a sequential fast hydrolysis reaction (Scheme 4, reaction A). 33,34 Yang et al have shown that in the presence of an amine group, such as in the case of 2, the amine is the first to be oxidized under neutral and basic conditions. When an excess of oxidant was used, it was suggested that the N-oxide intermediate can be further oxidized on the sulfur moiety at a slower rate.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…When an excess of oxidant was used, it was suggested that the N-oxide intermediate can be further oxidized on the sulfur moiety at a slower rate. 34 Moreover, tests we have conducted separately on diisopropylethylamine 15 (the amine "tail" of 2) under the same conditions (NIS, ACN/H 2 O) showed a very fast decomposition to acetaldehyde and diisopropylamine (Scheme 4, reaction B). A similar reaction was previously described for tertiary amines and NBS.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Oxidative Detoxification of Sulfur-Containing Chemical Warfare Agents by Electrophilic Iodine

et al. 2018

View full text Add to dashboard Cite

Mild oxidation of sulfur-containing chemical warfare agents was performed in organic medium by electrophilic iodine reagents. Kinetic experiments on sulfur mustard (HD) showed rapid (t 1/2 < 3 min) and selective oxidation to the nonvesicant sulfoxide product (HD-SO) in acetonitrile or propylene carbonate solutions (9% water added) containing excess N-iodosuccinimide (NIS). Molecular iodine solutions in these solvents led to similar results as with NIS but at much slower rates (t 1/2 ∼ 90 min). Higher donor number solvents, such as THF, DMF, or DMSO, showed slower rates with both iodine and NIS. The oxidation of the nerve agent O-ethyl-S-2-(N,N-diisopropylaminoethyl)methylphosphonothioate (VX) selectively to the nontoxic ethyl methylphosphonic acid product exhibited fast rates (t 1/2 = 6 min) using NIS in DMSO solution. In all other solvents tested with VX, rates were slower (t 1/2 ∼ 30–70 min). Oxidation experiments under the same conditions with chloroethyl ethyl sulfide (HD simulant) and O,S-diethyl methylphosphonothioate (VX simulant) led to much faster reaction rates. These transformations are believed to proceed through electrophilic iodine attack on the sulfur moiety and display solvent dependency based on the agents’ structural and chemical properties.

show abstract

“…31 P NMR studies of VX chemical shift as a function of pH were performed using a Varian 5 mm narrow bore liquids probe; typical solutions were 2 μL VX in 350 μL solvent (90°pulse width, 60 s recycle time). 13 C and 31 P NMR as a function of pH were also done using a Varian 10 mm liquids probe on the wide bore instrument; typical solutions were 25 μL VX in 700 μL solvent. The 10 mm liquids probe provided greater sensitivity but lower resolution due to the poorer shimming of the wide bore magnet.…”

Section: ■ Experimental Methodsmentioning

confidence: 99%

Speciation of VX in Aqueous Solutions

2013

View full text Add to dashboard Cite

31 P and 13 C NMR studies of the toxic chemical warfare agent VX [O-ethyl S-(2-N,N′-(diisopropylamino)ethyl) methylphosphonothioate] have been used to understand the reactivity in a wide variety of matrices. The presence of protonated VX has been invoked in many mechanisms of VX degradation and decontamination. A change of speciation of VX has been justified by a relatively large shift in the 31 P NMR chemical shift from about 55 ppm (in neat material or organic solvents) to >60 ppm (in aqueous solutions).This study shows that in acetonitrile/water mixtures and in aqueous solutions at a range of pH values, the 31 P NMR resonance was sensitive to the percentage water in the mixture, but was not sensitive to the pH of the solution. This result indicates that the 31 P chemical shift to >60 ppm is not associated with protonated VX, which is only present at pH < 8. However, the 13 C NMR resonances did respond to changes in the pH of the solution, indicating that these shifts are associated with protonation of the VX in acidic media.

show abstract

ChemInform Abstract: Oxidative Detoxification of Phosphonothiolates.

Abstract: The chemical nerve agent (I) is an unusually selective oxidation substrate.

Cited by 8 publications

References 1 publication

Decontamination of VX from Silicone: Characterization of Multicomponent Diffusion Effects

Decontamination of VX from Silicone: Characterization of Multicomponent Diffusion Effects

Oxidative Detoxification of Sulfur-Containing Chemical Warfare Agents by Electrophilic Iodine

Speciation of VX in Aqueous Solutions

Contact Info

Product

Resources

About