RADIATION-INDUCED REACTIONS OF 2,4,6-TRINITROTOLUENE IN AQUEOUS-SOLUTION

Radiolysis of aqueous solutions of TNT was examined to provide fundame ntal information concerning the reactions of TNT with radical species in water. gamma-Radiation was used in conjunction with radical scaveng ers to compare yields for radiation-induced TNT transformation under o xidizing and reducing conditions and in the presence and absence of ox ygen. Pulse radiolytic techniques were employed to determine rate cons tants and absorption spectra for the reactions of TNT with the hydroxy l radical and the aqueous electron. TNT was rapidly transformed under both reducing (1% tert-butyl alcohol, N-2 sparged) and oxidizing (N2O sparged) conditions although rates under reducing conditions were grea ter. The initial yield for transformation of a 350 mu mol L-1 TNT solu tion under reducing conditions was 0.14 mu mol/J as opposed to 0.10 mu mol/J measured in oxidizing conditions. The reactions of TNT with red uced oxygen species were found to be highly inefficient in aqueous sol ution. Although TNT is transformed by both oxidizing and reducing radi cals, TNT degradation yields in the absence of a radical scavenger wer e low, indicating that under these conditions there were significant s econdary reactions in which the species resulting from reactions betwe en TNT and the primary radicals further reacted to reform the parent c ompound. The bimolecular rate constant for the reaction between TNT an d (OH)-O-. was determined to he 4.3 x 10(8) mol(-1) s(-1). Byproduct a nalyses from gamma-radiolysis suggest that hydroxyl radical abstractio n of a methyl hydrogen to form the trinitrotoluyl radical is an initia l oxidative reaction. The bimolecular rate constant for the reaction b etween TNT and e(aq)(-) was measured as 3.5 x 10(10) mol(-1) s(-1). Th ese results provide quantitative and qualitative insight into the reac tions between TNT and the various aqueous radicals produced in many re mediation processes.