X- and gamma-radiolysis of phosphate esters. Electron spin resonance study by the spin trap technique

Abstract

Radicals formed at X- and γ-radiolysis of glass and liquid tri-n-butylphosphate /TBP/, di-n-butylphosphate /DBP/, di/2-ethylhexyl/phosphoric acid /DEHPA/, tri-p-tolylphosphate /TTP/ and di-n-butyl-n-butyl phopsphonate /DBBPN/ were studied using the technique of spin trap using C-phenyl-N-tert. butylnitrone /PBN/ and 2-methyl-2-nitrosopropane /MNP/ as spin trap agents. When using PBN, nitroxyl radicals generated by the spin trap of hydrogen atoms and labile radicals of phosphates or phosphonate were identified after irradiation in vacuum. Radiation-chemical yield of spin adducts was observed, as well as their thermal stability at 293 K, rate constants and half-time of decay and free activation energy of the decay of spin adducts. Mechanism of generation and decay of nitroxyl radicals is discussed. The spin adducts with MNP have a relatively low stability and superposition of some adducts spectra.