Kinetics and Mechanism of Decontamination Reaction of CEES in H2O2/[CnMIm]HCO3

A series of environmentally benign 1-n-alkyl-3-methylimidazolium bicarbonate ionic liquids(ILs) ([C(n)MIm] HCO3, n = 2, 4, 6, 8) was synthesized and hydrogen peroxide was employed in decontamination against 2-chloroethyl ethyl sulfide(CEES, a mustard agent simulant) in these ILs. The influencing factors such as ILs alkyl chain length, oxidant/CEES molar ratio and temperature were tested and the activation energy, reaction product in H2O2/[BMIm] HCO3 was analyzed. The results indicated that the solvents species can affect decontamination efficacy against CEES and they were in the following sequences: [BMIm] HCO3 > [EMIm] HCO3 > [HMIm] HCO3 > [OMIm] HCO3 > C2H5OH> H2O. In H2O2/[BMIm] HCO3 system, 99.58% of the CEES was oxidized mainly to corresponding sulfoxide after 30 min at the concentration of 20 mg/mL and O/S molar ratio of 10. The apparent activation energy of CEES oxidized by H2O2/[BMIm] HCO3 was 15.59 kJ/mol. Moreover, the superoxide radical anion(center dot O-2(-)) could be produced and oxidized ILs to 2-imidazolone, which inhibited the formation of corrosive sulfone. The result indicated that H2O2/[BMIm] HCO3 system may be a new option for decontamination against CEES.