A solvent-free solid catalyst for the selective and color-indicating ambient-air removal of sulfur mustard

Abstract

Bis(2-chloroethyl) sulfide or sulfur mustard (HD) is one of the highest-tonnage chemical warfare agents and one that is highly persistent in the environment. For decontamination, selective oxidation of HD to the substantially less toxic sulfoxide is crucial. We report here a solvent-free, solid, robust catalyst comprising hydrophobic salts of tribromide and nitrate, copper(II) nitrate hydrate, and a solid acid (NafionTM) for selective sulfoxidation using only ambient air at room temperature. This system rapidly removes HD as a neat liquid or a vapor. The mechanisms of these aerobic decontamination reactions are complex, and studies confirm reversible formation of a key intermediate, the bromosulfonium ion, and the role of Cu(II). The latter increases the rate four-fold by increasing the equilibrium concentration of bromosulfonium during turnover. Cu(II) also provides a colorimetric detection capability. Without HD, the solid is green, and with HD, it is brown. Bromine K-edge XANES and EXAFS studies confirm regeneration of tribromide under catalytic conditions. Diffuse reflectance infrared Fourier transform spectroscopy shows absorption of HD vapor and selective conversion to the desired sulfoxide, HDO, at the gas–solid interface.

Materials for the Simultaneous Entrapment and Catalytic Aerobic Oxidative Removal of Sulfur Mustard Simulants

“…13,14,26 2-Chloroethyl ethyl sulfoxide (CEESO) and 2chloroethyl ethyl sulfone (CEESO 2 ) oxidation standards were synthesized according to previous methods. 16,18,27 Gas chromatography (GC) data were collected on an Agilent Hewlett Packard (HP) 6890 GC system with an HP-5 phenyl methyl siloxane column and a flame ionization detector (FID). Fourier transform infrared spectroscopy (FTIR) data were obtained on a Nicolet iS10 FTIR spectrometer.…”

“…24,25 HD oxidation by nitrate/bromine catalysts is selective for the less-toxic sulfoxide product, HDO, as the unstable bromosulfonium intermediate cannot form second time from sulfoxide. 16 The addition of acid significantly improves the reaction rate for sulfide oxidation when using nitrate/bromine catalysts. 16,19…”

“…16 The addition of acid significantly improves the reaction rate for sulfide oxidation when using nitrate/bromine catalysts. 16,19…”

“…Recently, we reported the first solid formulation for aerobic oxidation of sulfur mustard using a nitrate/tribromide catalytic system. 16 The aerobic oxidation catalyst comprises a mixture of tribromide, nitrate, and a solid acid catalyst such as Nafion (abbreviated NO x Br x H + ). This catalytic system is fast and selective for sulfoxidation of live agent HD in both the liquid and vapor phases.…”

The Association Between the rs1805329 of Rad23B Polymorphism and Severity of Lung Complications of Patients Exposed to Sulfur Mustard in Long Term

“…ulfur Mustard (SM) or bis(2-chloroethyl) Sulfide (HD) is among the chemotoxic agents that cause Biologically destructive effects and is highly persistent in the environment [1]. In World War I, this substance was first used in chemical warfare [2].…”