Degradation of chlorinated benzaldehydes in aqueous solutions by UV-irradiation

Abstract

Photoinduced degradation of chlorinated benzaldehydes was investigated using UV light with λ = 253.7 nm in aerated aqueous solutions. Substrate degradation rate as expressed by first order reaction kinetics revealed rate constants, k; 7.45×10−3 min-1, 3.90×10−3 min-1 and 3.90×11−2 min-1 for 2- chlorobenzaldehyde, 3-chlorobenzaldehyde and 4-chlorobenzaldehyde respectively. The decomposition of the substrates was related to the formation of chloride and formaldehyde by homolytic cleavage processes. initial quantum yields and photochemical “GiPH -values” are reported for the degradation of the substrates. Based on the qualitative HPLC analysis, a probable reaction mechanism for the photoinduced degradation of chlorinated benzaldehydes is also presented.