Decontamination of Paraoxon and Parathion on Sensitive Equipment Materials by Catalytic Methanolysis

Abstract

Sensitive equipment materials were decontaminated from organophosphorus compounds paraoxon or parathion by immersion into a catalytic reactive solution and by spraying with the same solution. Immersion of contaminated material samples into methanol-based catalytic solutions resulted in an effective decontamination. Greater than 99% decontamination was observed for paraoxon on high-impact polystyrene (HI-PS) over 15 min of reaction time. Under the same process conditions, the decontamination from parathion did not exceed 95%. The catalytic decompositions of paraoxon and parathion followed firstorder reaction kinetics with rate constants of 5.4 × 10 −3 and 1.3 × 10 −3 s −1 , respectively. These values were by an order of a magnitude lower than the respective rate constants reported for homogeneous reactions in a methanol solution. Decontamination by spraying the catalyst on the contaminated surface revealed that multiple applications would be required to overcome a rapid evaporation of methanol from the surface and an associated loss of catalytic activity.

The Cu- and Zn-complex-catalyzed methanolysis of the chemical warfare nerve agents soman, sarin, and VX

“…An alternative method for the destruction of chemical warfare nerve agents, which would eliminate the aforementioned drawbacks, has already been developed and its efficiency was proved in the case of several chemical warfare nerve agent simulants [14e17]. This method uses a catalytic system containing La 3þ ions capable of accelerating the methanolysis of paraoxon by a factor of up to 10 9 [18,19]. Methanolysis possesses several fundamental advantages over hydrolysis.…”