The Radiation Chemistry of CMPO: Part 1. Gamma Radiolysis

The role of organic solvent radical cations in separations ligand degradation

“…However, for the -G CMPO data previously reported [6] to be consistent with the measured kinetics, the charge transfer reaction that occurs with the complex would have to have to regenerate free unchanged CMPO (Reaction 9) whereas the charge transfer with the free CMPO would directly result in ligand degradation (Reaction 8).…”

“…In either application the CMPO-containing solvent would see high radiation doses, and thus the stability of the ligand and the nature of its degradation products are of importance. The gamma-ray radiolysis of CMPO has been previously investigated with regard to its degradation products and G-values for decomposition, [2][3][4][5][6] however, there are only three reports concerning the alpha-radiolysis of CMPO, including one from this journal. [7][8][9].…”

“…The results are compared to our previous reports of the rates of CMPO degradation in gamma-irradiations under similar solution conditions, where it was observed that pre-contact of nitric acid provided a protecting effect of CMPO degradation. [6] The decrease in the CMPO degradation rate (-G CMPO ) was attributed to the protective effect of the formation of a CMPOÁHNO 3 complex in dodecane [6] …”

A Comparison of theγ-Radiolysis of TODGA and T(EH)DGA Using UHPLC-ESI-MS Analysis

“…[29] Degradation was also observed for γ-irradiated CMPO (which contains a phosphoryl moiety) in n-dodecane; Downloaded by [New York University] at 23:55 14 June 2015 however, in this case the degradation was mitigated by the presence of nitric acid, suggesting a slower rate constant for the reaction of the n-dodecane radical with CMPO than was measured here for TODGA. [27] CONCLUSIONS The results of this study suggest that there is no difference in the γ-radiolysis of TODGA and T(EH)DGA in n-dodecane, nor is there a difference in chemistry that depends on the acidity of an aqueous phase in contact with the DGAs in n-dodecane. In both molecules, the major sites for radiolytic attack are the bonds within the diglycolamide functional group, specifically the C−O ether , N−C carbonyl , and the N−C side-chain bonds, and to a lesser extent the C−C carbonyl bond, while the bonds in the N−alkyl side-chains do not participate.…”

“…6b) precludes a definitive statement in this regard. However, it is noted that the presence of nitric acid was shown to favor amine bond rupture for TODGA by Sugo et al [14] for the malonamide dimethyl dioctyl hexylethoxymalonamide (DMDOHEMA) by Berthon et al [26] and for octylphenyl-N,N-diisobutylcarbamoyl phosphine oxide by Mincher et al [27] …”