Hydrolytic Reactions of Methylfluorophosphonates with Cyclodextrins

Abstract

Reactions of three methylfluorophosphonates (isopropyl, 1,2,2-trimethylpropyl, and cyclohexyl) with α-, β- and γ-cyclodextrins were investigated. The cyclodextrins were found to react with stereoisomers of the methylfluorophosphonates at different rates depending on the location of the substituents at the phosphorus atom. The dependence of the rate increase on cyclodextrin concentration showed a saturation effect. The reactivity of the inclusion complexes of the cyclodextrins with the methylfluorophosphonates depended on the size of the alkyl part of the phosphonate molecule as well as on the size of the cavity of the cyclodextrins. Dependences of the reaction rates on temperature and pH of the reaction medium were recorded. Kinetic data have been used to evaluate the cyclodextrins as the catalysts.