Hydrolysis of methyl bromide, ethyl bromide, chloropicrin, 1,4-dichloro-2-butene, and other halogenated hydrocarbons

The hydrolysis of halogenated hydrocarbons in general, and of four soil fumigants (methyl and ethyl bromide, chloropicrin, and 1,4-dichloro-2-butene), in particular, is reviewed. Experimental methods are discussed, predictive generalizations are presented, and new experimental data on the hydrolysis of the fumigants are given Some semi-quantitative results are mentioned concerning adsorption and enzymatic degradation of methyl bromide and chloropicrin by plant materials. At 25 degrees C, the hydrolysis half-lives of both methyl and ethyl bromide are about 21 days, while at 35 degrees C this value is about 5 days. The 25 degrees C hydrolysis half-life for dichlorobutene is about 3 hours, but chloropicrin has an extrapolated half-life of 500,000 years. Enzymatic dehalogenation of methyl bromide and chloropicrin provides a transformation pathway that results in environmental half-lives of less than 20 hours.