Morpholine derivatives as low volatility bases toward hydrolysis of toxic organophosphorus chemicals

Abstract

Chemical warfare agents (CWAs), particularly organophosphorous nerve agents, are among the most toxic chemicals known to humans. While they are banned for use internationally, their unsanctioned use and stockpiling still pose significant threats to society. Metal–organic frameworks (MOFs) are promising candidates for the hydrolysis of these chemicals into less toxic products. MOFs are crystalline coordination polymers with permanent porosity. Due to their tunability, they have been widely applied to many fields, such as gas storage and separations, sensing, catalysis, and drug delivery.For the practical application of this technology in the field, heterogenization of the base is necessary to achieve solid-state hydrolysis. In this study, we take one step toward this realization by showing effective hydrolysis of the nerve agent simulant DMNP by MOF-808 in the presence of five low-volatility morpholine compounds.These novel compounds, which are soluble and stable in water, were synthesized by us in four steps. While N-ethylmorpholine still shows a slightly higher rate of hydrolysis, the viscous bases show appreciable degradation of DMNP at even lower concentrations, due in part to multiple basic amine sites.