Simple and highly active strontium-based catalyst for detoxification of an organophosphorus chemical warfare agent simulant

Johann V Hemmer,Gizelle I Almerindo,Eduardo H Wanderlind,Andressa K Emmerich,Theodoro M Wagner,Jonathan R U Adão,Heitor A G Bazani,Carlos E M Campos

doi:10.1007/s43153-020-00048-4

Abstract

A mixture of strontium carbonate, hydroxide and oxide was prepared by thermal decomposition of SrCO3 and employed as catalyst in the decomposition of the chemical warfare agent simulant methyl paraoxon, by means of its transesterification with 1-propanol. The catalyst, which was characterized by N2 physisorption (BET method), temperature programmed desorption (CO2-TPD), Fourier Transform Infrared spectroscopy (FTIR), X-Ray diffraction (XRD) and Raman spectroscopy, promoted rate enhancements of the order of 107-fold in comparison to the spontaneous propanolysis reaction, the greatest catalytic effect promoted by metal oxide-based catalysts ever reported for this reaction. Compared to the fresh catalyst, the catalyst directly stored in the reaction solvent showed similar catalytic performance. Analysis of the reaction products by liquid chromatography with electrospray ionization mass spectrometry detection confirmed the transesterification of the substrate leading to dimethyl n-propyl phosphate, a product structurally related to a family of trialkyl phosphate flame retardants.

Highlights

The Organization for the Prohibition of Chemical Weapons (OPCW) establishes that chemical warfare agents throughout the world must be declared and destroyed safely and quickly (Forman and Timperley 2019)
We have investigated the catalytic decomposition of methyl paraoxon (Zimmermann et al 2013; Almerindo et al 2016), a simulant of organophosphorus chemical warfare agents typically employed in chemical detoxification research, as a precautionary measure due to the high toxicity exhibited by the organophosphorus biocides (Trotochaud et al 2017; Balow et al 2018; Mondloch et al 2015)
It is noteworthy that in these systems, methyl paraoxon is converted into dimethyl n-propyl phosphate, a compound that is structurally related to a family of trialkyl phosphates employed as flame retardants (Venier et al 2015)

Summary

Introduction

The Organization for the Prohibition of Chemical Weapons (OPCW) establishes that chemical warfare agents throughout the world must be declared and destroyed safely and quickly (Forman and Timperley 2019). Sarin itself is categorized as an organophosphorus (OP) chemical warfare agent, a class of compounds that attacks the nervous system through the inhibition of acetylcholinesterase, a process that can be irreversible and lead to death depending on the degree of intoxication and the time taken to administer an antidote (Delfino et al 2009; Mercey et al 2012; Chen et al 2018; Costanzi et al 2018). In this context, several research groups worldwide have directed efforts toward the investigation of homogeneous. A Mg2+/Al3+ mixed oxide featuring an incipient spinel phase employed in the propanolysis of methyl paraoxon was shown to be catalytically active in the transesterification of a wide range of other phosphate triesters, including triaryl substrates that can be conveniently converted into trialkyl ones (Zimmermann et al 2018)

Methods

Results

Conclusion