Oxidative Neutralization of Mustard‐Gas Simulants in an On‐Board Flow Device with In‐Line NMR Monitoring

The fast and effective neutralization of the mustard‐gas simulant 2‐chloroethyl ethyl sulfide (CEES) using a simple and portable continuous flow device is reported. Neutralization takes place through a fully selective sulfoxidation by a stable source of hydrogen peroxide (alcoholic solution of urea–H₂O₂ adduct/MeSO₃H freshly prepared). The reaction progress can be monitored with an in‐line benchtop NMR spectrometer, allowing a real‐time adjustment of reaction conditions. Inherent features of millireactors, that is, perfect control of mixing, heat and reaction time, allowed the neutralization of 25 g of pure CEES within 46 minutes in a 21.5 mL millireactor (t ^R =3.9 minutes). This device, which relies on affordable and nontoxic reagents, fits into a suitcase, and can be deployed by police/military forces directly on the attack site.