Hydrolysis of nerve agent simulants by synergistic effects of tetraminecobalt(III) and microemulsions

Hydrolysis of nerve agent simulants, namely, 4-nitrophenyl diphenyl phosphate (NPDPP), 4-nitrophenyl phosphate (NPP) and 4-thiophenyl diphenyl phosphate (TPDPP) assisted by hydroxoaquatetraminecobalt(III) in microemulsion media were investigated at 10(-4) M concentration. The reactions for NPDPP and NPP were monitored by measuring the absorbance of the nitrophenolate ion produced in the reaction aliquots with time. The disappearance of TPDPP and the appearance of thiophenol was followed by TLC (4:2:1 hexane/ethyl acetate/ethanol) on silica. The order of effectiveness of the N-4 ligand in Co(III)(N-4)(aq) complexes at pH 6.5 towards hydrolysis of the above nerve agent simulants was found to be trpn > (tn(2)) > (en(2)) (trpn = tris(3-aminopropyl)amine, tn = trimethylenediamine en = ethylenediamine). The possible application of the above systems for environmental decontamination is discussed. (C) 1998 Elsevier Science S.A.