Shunji Ishikura

Chemical changes of organic compounds in chlorinated water : XI. Thin-layer chromatographic fractionation of ames mutagenic compounds in chlorine-treated 4-methylphenol solution☆

The diethyl ether extract from an aqueous solution of 4-methylphenol after treatment with hypochlorite was mutagenic to the Ames Salmonella test strain TA100 in the absence of liver homogenate. Gas chromatography-mass spectrometry (GC-MS) showed the occurrence of, at least, twenty compounds in the extract: chloro-4-methylphenols, chlorohydroxy-4-methylquinones and chlorinated 4-methylphenol dimers. The diethyl ether extract was fractionated into several fractions by silica gel and polyamide thin-layer chromatography (TLC). The fractionated components were then examined for mutagenicity by means of Ames assays, and were identified by GC-MS. TLC fractionation of the extract revealed that the major components present in the extract are not mutagenic, but minor components (less than 4% of the total extract) are mutagenic. GC-MS analysis indicated the presence of chlorinated 4-methylphenol dimers in the fraction which exhibited the highest mutagenicity.

Chemical changes of organic compounds in chlorinated water : IX. Formation of polychlorinated phenoxyphenols during the reaction of phenol with hypochlorite in dilute aqueous solution

Abstract Aqueous phenol solutions were treated with hypochlorite at 20°C under various experimental conditions. Changes in the composition of the chlorination products in water were determined by using gas chromatographic (GC) and GC-mass spectrometric analyses of diethyl ether extracts. Chlorination of phenol in dilute aqueous solution produced a series of highly chlorinated compounds, including chlorophenols, chlorobenzoquinones and chlorinated carboxylic acids. Tentative identifications were also made for other compounds with the following proposed molecular formulae: C 12 H 8 Cl 2 O 2 , C 12 H 7 Cl 3 O 2 , C 12 H 6 Cl 4 O 2 and C 12 H 5 Cl 5 O 2 . On the basis of thin-layer chromatographic and GC behaviour, these compounds are considered to be chlorinated phenoxyphenols. Production of some of these compounds is dependent on the equivalents of chlorine per mole of compound and the reaction pH. These results show that treatment with chlorine of water contaminated with phenolic compounds leads to the production of chlorinated phenoxyphenols.

Gas chromatographic identification and determination of chlorinated quinones formed during chlorination of dihydric phenols with hypochlorite in dilute aqueous solution

This paper describes gas chromatographic identification of chlorinated quinones present in water on the basis of plots of log tR against number of chlorine atoms in the molecule. The plots for each homologous series of chlorinated phenols, hydroquinones (HQ) and p-benzoquinone chromatographed on polar and non-polar columns are found to be linear, with few exceptions. Mono-,di- and trichlorinated quinones are the principal intermediate products during chlorinations of catechol, resorcinol, HQ and methyl-HQ with aqueous hypochlorite. The residual intermediate compounds formed from resorcinol and methyl-HQ are present in higher concentrations in chlorinated water than those of other dihydric phenols.

Chemical changes of organic compounds in chlorinated water : X. Formation of polychlorinated methylphenoxymethylphenols (predioxins) during chlorination of methylphenols in dilute aqueous solution

Abstract Aqueous methylphenol ( o -, m - and p -isomers) solutions were treated with hypochlorite at 20°C under various experimental conditions. Changes in the compositions of the chlorination products in water were determined by using gas chromatographic (GC) and GC—mass spectrometric analyses of diethyl ether extracts. The chlorination of methylphenols in dilute aqueous solutions produced a series of highly chlorinated compounds, including chloromethylphenols, chloromethylbenzoquinones and chlorinated carboxylic acids. Tentative identifications were also made for other compounds with following molecular formulae: C 14 H 5 Cl 2 O 2 , C 14 H 4 Cl 3 O 2 and C 14 H 3 Cl 4 O 2 . On the basis of the thin-layer chromatographic and GC behaviour and mass fragmentation patters, the compounds are considered to be chlorinated methylphenoxymethylphenols. The production of some of these compounds is dependent on the number of equivalents of chlorine per mol of compound and the reaction pH. These results show that treatment with chlorine of water contaminated with phenolic compounds leads to the production of chlorinated phenoxyphenols (predioxins), which are precursors of the highly toxic chlorinated dibenzo- p -dioxins.

Chemical changes of organic compounds in chlorinated water : VI. Gas chromatographic and mass spectrometric studies of the reactions of phenylphenols with hypochlorite in dilute aqueous solution

Abstract Diethyl ether-extracted products obtained from phenylphenol solutions after treatment with hypochlorite under various conditions have been investigated for their nature and contents of chlorination products in water. The ether extracts were chromatographed on polar and non-polar gas—liquid chromatographic (GLC) columns and the peaks were assigned on the basis of plots of log t R against the number of expected chlorine atoms. They were subsequently identified from the mass spectra of the extracts. The GLC and mass spectral analyses of these products indicated that the reactions involve chlorination to chlorophenylphenols (A), oxidation of compounds A to chlorophenylquinones (B), oxidative degradation of compounds B to phenylcarboxylic acids and condensation of compounds A to the corresponding ethers and dioxins. The residual amounts of chlorinated compounds of phenylphenols in water were found to be dependent on the pH of the solution.