The effect of chlorination on organocyanide compounds

Results are presented that explore the possibility of organocyanide compounds in wastewater contributing to elevated cyanide levels in the chlorinated effluents of publicly owned treatment works. Four model compounds, acetonitrile, amygdalin, cyanocobalamin, and 2-acetoxy-3-butenenitrile, were selected and tested with varying chlorine dosages for release of cyanide by total and diffusible cyanide procedures. The coenzyme form of vitamin B12, which does not contain cyanide, was also tested. It was found that acetonitrile and amygdalin do not yield cyanide with or without chlorination, cyanocobalamin had increased release with increased chlorine dosages, and 2-acetoxy-3-butenenitrile had generally decreased release of cyanide with increased chlorine dosages. Both cyanocobalamin and coenzyme vitamin B12 gave evidence of the formation of the cobalt-cyanide complex after chlorination, even though the molecular structure of the coenzyme vitamin B12 contains no cyanide.