|Zheng, Wei - UNIVERSITY OF CALIFORNIA|
Submitted to: American Chemical Society National Meeting
Publication Type: Abstract Only
Publication Acceptance Date: September 10, 2006
Publication Date: September 14, 2006
Citation: Zheng, W., Yates, S.R. 2006. Transformation of two chlorinated fumigants by hydrogen sulfide species. American Chemical Society National Meeting. pp# AGRO-7 Technical Abstract: The chlorinated fumigants chloropicrin and 1,3-dichloropropene (1,3-D) are extensively used to control soilborne pests. Transformation of these two pesticides by hydrogen sulfide species (H2S and HS-) was examined in well-defined anoxic aqueous solutions. Chloropicrin underwent an extremely rapid redox reaction in the hydrogen sulfide solution. Transformation products indicated reductive dechlorination of chloropicrin by hydrogen sulfide species to produce dichloro- and chloronitromethane. For 1,3-D, kinetics and transformation products analysis revealed that the reaction between 1,3-D and hydrogen sulfide species is an SN2 nucleophilic substitution process, in which the chlorine at C3 of 1,3-D is substituted by the sulfur nucleophile to form corresponding mercaptans. The transformation of chloropicrin and 1,3-D in hydrogen sulfide solution significantly increased with increasing pH, suggesting that the reactivity of hydrogen sulfide species stems primarily from HS-. Because of the relatively low smell threshold values and potential persistence of organic sulfur products, the environmental behaviors of transformation products of 1,3-D and HS- need be assessed.