A possible new disinfection by-product—2-chloro-5-oxo-3-hexene diacyl chloride (COHC)—in formation of MX by chlorinating model compounds

MX was widely considered as one of the most important disinfection by-products (DPBs) and as the strong carcinogen in the chlorinated drinking water. Some model compounds which have been classified into four families were chlorinated at laboratory conditions. MX was produced only in the chlorinated substituted aromatic aldehydes and amino acids, while a possible new compound (COHC) was found in some substituted aromatic aldehydes, chlorinated substituted aromatic acids and phenols. Through the analysis of the peaks presented in mass spectrum, the composition and structure of the new compound are proposed as 2-chloro-5-oxo-3-hexene diacyl chloride (COHC) which could cause interference in the detection of MX. COHC has also been found in drinking water and extracted chlorinated fulvic acid solution from the sediment and water of Tai Lake, so it should bring about more attention.