Radiolytic transformations of methyltrioctylammonium carbonate

Methyltrioctylammonium carbonate (TOMAC) serves as a reference extractant in the CARBEX concept for reprocessing spent nuclear fuel. The present work is a study of radiolysis of undiluted TOMAC with 3 MeV electrons at an absorbed dose of up to 150 kGy. Radiolysis results in the degradation of both carbonate anions and tetraalkylammonium cations. Accordingly, CO₂ (yield about 0.206 μmol J⁻¹) and alkylamines (including dimers) with different alkyl compositions are formed. The change in alkyl substituents is accompanied by the formation of H₂ (yield about 0.25 μmol J⁻¹). The observed yields of liquid radiolysis products are about 0.40 μmol J⁻¹, while the yield of radiolytic degradation of TOMAC is about 0.36 μmol J⁻¹. The results indicate a relatively high stability of TOMAC to radiolysis and are consistent with literature data on the effect of radiation on the hydrodynamic and extraction properties of TOMAC.