Nuclear Magnetic Resonance Study of the Hydrolysis of Diethyl Methylphosphonite

Abstract

The products of the hydrolysis reactions of diethyl methylphosphonite at room temperature have been elucidated by means of proton nuclear magnetic resonance. The reaction was followed by observing the methyl-hydrogen resonance, phosphorus-hydrogen resonance, methylenehydrogen resonance, and hydroxyl-hydrogen resonance. Upon addition of up to one mole of water per mole of diethyl methylphosphonite, ethyl hydrogen methylphosphinate was produced in a very rapid and complete reaction. Upon addition of greater than one mole of water—up to two moles of water per mole of diethyl methylphosphonite—the ethyl hydrogen methylphosphinate that was produced was further hydrolyzed to dihydrogen methylphosphinate in a very slow reaction. At ratios of two or more moles of water per mole of diethyl methylphosphonite, only dihydrogen methylphosphinate and ethanol were observed in solution after the reactions had come to completion. Trivalent phosphorus hydrolysis products were not observed in this reaction sequence. The chemical shifts, spin—spin coupling constants, and analytical data are described.