Sustained Room Temperature Decomposition of Dimethyl Methylphosphonate (DMMP) by O3 on Alumina-Supported MnOx

Abstract

Dimethyl methylphosphonate (DMMP) is a widely used simulant for chemical warfare agents and pesticides. This work examined the room temperature reaction of DMMP with ozone on alumina-supported manganese oxide. The reaction on the MnOx/Al2O3 surface shows a long period (approximately nine hours) of relatively constant, sustained product formation, yielding five times as much gas-phase carbon, in the form of CO2 and CO, as does the same reaction on supported iron oxide. CO2 and CO (COx) were the major products observed, with most experiments yielding equal amounts of the two gases. The DMMP decomposition reaction still appears to be stoichiometric, as observed in investigations with other supported oxides, but in this case, at the lower loadings, virtually every manganese ion on the support is reactive. Additionally, the number of COx species produced per manganese ion is in excess of four at the lower manganese loadings and on average each DMMP molecule that reacts yields one molecule of CO2 and one of CO....