The role of heterogeneity in the kinetics of a surface reactionI. Infrared characterization of the adsorption structures of organophosphonates and their decomposition
Infrared investigation shows that isopropyl methylphosphonofluoridate (sarin) is strongly adsorbed on γ-alumina via its phosphoryl oxygen. Two decomposition reactions are observed: either propene is liberated as a result of dealkylation of the adsorbed species or the P F bond is hydrolyzed. Fluorine released in the latter reaction is also adsorbed; the remaining phosphorus compound is bonded to the surface via its POO grouping. The hydrolysis reaction, which is the predominant process, is activated by basic surface sites. Water accelerates this reaction. The surface is inactivated by adsorption of HF. The hydrolysis proceeds considerably faster over magnesium oxide.