Formaldehyde formation from tertiary amine derivatives during chlorination.

Abstract In May 2012, formaldehyde (FA) precursor contamination in the Tone River Basin led to the suspension of water supply to approximately 360,000 homes, which affected approximately 870,000 people in the Tokyo Metropolitan Area. The discharge of industrial effluents containing hexamethylenetetramine (HMT), a tertiary amine and FA precursor, without proper treatment resulted in the formation of FA during chlorination at water purification plants. Tertiary amines are known to be the precursors of aldehydes upon chlorination. In this study, FA formation from 29 separate amine derivatives during chlorination was investigated to determine any other potential causes of this water quality accident. The FA formation yield also included FA formation by the autolysis of the target compounds as well as the chlorination of the autolysis products. The FA molar formation yield of HMT was the highest after 24 h of chlorination (440%). Among the various tertiary amine derivatives containing N -methyl groups, tertiary amines and hydrazines were found to be strong FA precursors because the FA molar formation yields per N -methyl group ranged from 25% to 45% (with a mean of 38%) and from 35% to 45% (with a mean of 41%), respectively. Guanidines and sulfamides containing N -methyl groups were also FA precursors but they exhibited lower FA molar formation yields per N -methyl group. The FA molar formation yields of the remaining compounds were