Photodechlorination of 3,3'-dichlorobenzidine in water.
Laboratory experiments have been conducted to elucidate the photochemical behavior of 3,3'-dichlorobenzidine (DCB) and its congeners in aquatic systems. Photodechlorination of DCB was observed in aqueous samples that were irradiated with monochromatic radiation from a variable-wavelength laser at several wavelengths in the range 300 nm < or = lambda < or = 360 nm. Analytical measurements performed by high-performance liquid chromatography (HPLC) and Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry revealed that 3-chlorobenzidine (MCB) was produced as a transient intermediate in the photodechlorination process, with subsequent photodechlorination to yield benzidine as a stable photoproduct. Data obtained from these measurements also suggest the existence of other (unidentified) reaction pathways and products. The time-course measurements of chlorobenzidine congener concentrations and irradiance history were combined with a simple reaction model to develop estimates of reaction kinetics. Model predictions were consistent with results obtained for all wavelengths investigated.
Nyman
Marianne C
MC
Department of Civil and Environmental Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA. nymanm@rpi.edu
Haber
Ken S
KS
Kenttämaa
Hilkka I
HI
Blatchley
Ernest R
ER
D015101:3,3'-Dichlorobenzidine / Q000737:chemistry*; D002273:Carcinogens / Q000737:chemistry*; D002713:Chlorine / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D007700:Kinetics; D007834:Lasers; D010777:Photochemistry; D017550:Spectroscopy, Fourier Transform Infrared; D014874:Water Pollutants, Chemical / Q000032:analysis*
D002273:Carcinogens; D014874:Water Pollutants, Chemical; D015101:3,3'-Dichlorobenzidine; D002713:Chlorine