Issue 24, 2011

The reactivity of quaternary ammonium- versus potassium- fluorides supported on metal oxides: paving the way to an instantaneous detoxification of chemical warfare agents

Abstract

The reactions of the chemical warfare agents (CWAs) 2,2′-dichloroethyl sulfide (HD), O-ethyl S-2-(diisopropylamino)-ethyl methylphosphonothioate (VX) and isopropyl methylphosphonofluoridate (GB) with various metal oxide-supported quaternary ammonium fluorides (QAF) and/or potassium fluoride (KF) reagents are described. These active sorbents, which were prepared by a modified procedure, include alumina, silica and titania, enriched with “available” (not bound to the surface) fluoride ions. Alumina-based fluoride reagents were found to be more active than their silica or titania counterparts. QAF/Al2O3 reagents, compared to KF/Al2O3, exhibit an exceptional reactivity toward HD, as demonstrated both in reaction rates and product identity. For example, with TBAF, t1/2 is 15 min for the formation of the elimination product divinyl sulfide (DVS), while with KF, t1/2 is 10 h for the formation of the hydrolysis product thiodiglycol (TDG). On the other hand, both sorbents reacted similarly against the nerve agents GB or VX. In order to increase the “available” fluoride content on the solid surface, the mixed active sorbent TBAF/KF/Al2O3 (20/20/60) was developed. On this powder, all three CWAs were degraded instantaneously at the low loading of 1 wt% (t1/2 < 2 min) and rapidly at the higher loadings of 5–10 wt% (t1/2 of minutes scale). We assume that the relatively large amount of inorganic fluoride (KF) acts synergistically as a reservoir for the more reactive organic fluorides (TBAF). Moreover, the alumina surface hydroxyl groups may also operate as a water reservoir for the hydrolysis of VX or GB. Therefore, TBAF/KF/Al2O3 might be considered as a promising destructive sorbent for CWAs.

Graphical abstract: The reactivity of quaternary ammonium- versus potassium- fluorides supported on metal oxides: paving the way to an instantaneous detoxification of chemical warfare agents

Supplementary files

Article information

Article type
Paper
Submitted
10 Jul 2011
Accepted
15 Sep 2011
First published
16 Sep 2011

Org. Biomol. Chem., 2011,9, 8445-8451

The reactivity of quaternary ammonium- versus potassium- fluorides supported on metal oxides: paving the way to an instantaneous detoxification of chemical warfare agents

Y. Zafrani, L. Yehezkel, M. Goldvaser, D. Marciano, D. Waysbort, E. Gershonov and I. Columbus, Org. Biomol. Chem., 2011, 9, 8445 DOI: 10.1039/C1OB06136D

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