Development of chemical methods for individual decontamination of organophosphorus compounds

Abstract

The methods of individual decontamination of organophosphorus esters of paralytic action were studied using the decontamination of paraoxon (O, O-diethyl-O-4-nitrophenylphosphate) and methyl parathion (O, O-dimethyl-O-4-nitrophenylthiophosphate) from solid surfaces (metal, fabric, plastic) as an example. The mixtures of urea hydrogen peroxide, boric acid, cetylpyridinium chloride and montmorillonite nanoclay as decontamination systems were studied. The study showed that application of the micellar system together with nanoclays significantly increases a degree of adsorption of substrates from an infected surface. At the same time, the presence of an activator (boric acid) in systems with urea hydrogen peroxide contributes to an increase in the reaction rate in micellar medium by almost 20 times comparing with systems without activation. It was established that the studied micellar systems preserved the supernucleophilicity of НОО – -anion in relation to electrophilic substrates – paraoxon and methyl parathion. It was concluded that the presence of montmorillonite (sodium- and organomodified ones) increased the magnitude of α effect, both in systems with urea hydrogen peroxide only and in systems with boric acid activator. The effect of the acceleration of decomposition of organophosphorus substrates in micellar medium by montmorillonite derivatives was established. This fact could be used for the design of «green» decontamination systems of fast action. An analysis of data on the rate of deactivation of paraoxon and methylparathion on solid surfaces in the studied micellar decontamination systems made it possible to choose the system based on urea hydrogen peroxide, boric acid, cetyl pyridinium chloride and organomodified montmorillonite as the optimal system. A comparison was performed of the periods of half-lives of paraoxon and methylparathion in the studied micellar systems with the known, and applied in NATO subdivisions, decontamination systems. It was concluded that the rates of decontamination in the proposed systems are higher or not less than the rates in the known systems. At the same time, the proposed systems based on solid source of hydrogen peroxide have advantages in terms of environmental safety, manufacturability, and stability. The parameters of the decontamination rate and the degree of decomposition of paraoxon and methyl parathion gives us possibility to recommend the micellar systems as promising for individual deactivation of organophosphorus compounds. The development of fast-acting decontamination formulations, which are mild in their effects on a human body and are environmentally friendly, is a necessary and urgent task among a number of technological solutions for neutralization of toxic organophosphorus substrates, such as pesticides, chemical weapons components and active pharmaceutical ingredients