Mass spectrometric study of the radiolysis of di-(2-ethylhexyl)phosphoric acid

Abstract

A mass spectrometric study on DEHPA was carried out and compared with radiolysis data on DEHPA for γ-irradiation in the liquid phase. The mass spectra of DEHPA show an extremely low intensity of parent ion and the presence of double rearrangement ions of (RO)P(OH) ⁺₃ and P(OH) ⁺₄ , where R is the 2-ethylhexyl group. The appearance potentials of the principal ions in the mass spectrum were determined and the dissociation processes of DEHPA in the phase discussed. The fragment ions show good agreement with the results in the liquid phase where the mono-ester, orthophosphoric acid, octane and heptane were formed by the dealkylation, however, the peak intensities of some fragment ions in the mass spectrum differ from the radiolytic yields of the corresponding products. These differences imply the significant role of neutralization and recombination reactions in the liquid phase radiolysis.