Comparison of the Dehalogenation of Dihalomethanes (CH2XI, where X = Cl, Br, I) Following Ultraviolet Photolysis in Aqueous and NaCl Saltwater Environments

The ultraviolet photolysis of low concentrations of CH2XI (X = Cl, Br, I) were investigated in water and saltwater solutions by photochemistry and picosecond time-resolved resonance Raman spectroscopy. Photolysis in both kinds of solutions formed mostly CH2(OH)2 and HI and HX products. However, photolysis of the CH2XI molecules in saltwater resulted in production of some CH2XCl products not observed in aqueous solutions without salt present. The appearance of these new products in saltwater solutions is accompanied by a decrease in the amount of CH2(OH)2, HI, and HX products compared to photolysis in aqueous solutions without salt present. The possible implications for photolysis of CH2XI and other polyhalomethanes in seawater and other salt aqueous environments compared to nonsaltwater solvated environments is briefly discussed.