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

• Type of Material: Article
• Authors: Daniel L Collins-Wildman, Emory University; Kevin P Sullivan, Emory University; Yurii V Geletii, Emory University; Victoria G Snider, Emory University; Wesley O Gordon, US Army; Alex Balboa, US Army; Yiyao Tian, Stony Brook University; Rachel M Slaugenhaupt, Emory University; Alexey Kaledin, Emory University; Christopherr J Karwacki, US Army; Anatoly I Frenkel, Stony Brook University; Djamaladdin Musaev, Emory University; Craig Hill, Emory University
• Language: English
• Date: 2021-03-08
• Publisher: NATURE PORTFOLIO
• Publication Version: Final Published Version
• Copyright Statement: © The Author(s) 2021
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1038/s42004-021-00465-7
• Title of Journal or Parent Work: COMMUNICATIONS CHEMISTRY
• Volume: 4
• Issue: 1
• Start Page: 33
• End Page: 33
• Keywords: RAY-ABSORPTION SPECTROSCOPY; Physical Sciences; Science & Technology; Chemistry; SULFOXIDES; SULFIDES; OXIDATION; Chemistry, Multidisciplinary; DECONTAMINATION; HETEROGENEOUS CATALYST; BROMIDE COMPLEXES; TRIBROMIDE; EQUILIBRIUM; ACETONITRILE
• Research Categories: Chemistry, General

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.