title: Kinetics and mechanism of the mercury(II)-assisted hydrolysis of methyl iodide.
abstract: The kinetics and mechanism of the reaction of aqueous Hg(II) with methyl iodide have been investigated. The overall reaction is best described as Hg(II)-assisted hydrolysis, resulting in quantitative formation of methanol and, in the presence of excess methyl iodide, ultimately, HgI2 via the intermediate HgI+. The kinetics are biexponential when methyl iodide is in excess. At 25 degrees C, the acceleration provided by Hg2+ is 7.5 times greater than that caused by HgI+, while assistance of hydrolysis was not observed for HgI2. Thus, the reactions are not catalytic in Hg(II). The kinetics are consistent with an SN2-M+ mechanism involving electrophilic attack at iodide. As expected, methylation of mercury is not a reaction pathway; traces of methylmercury(II) are artifacts of the extraction/preconcentration procedure used for methylmercury analysis.
authors.affiliation: Department of Chemistry, University of Ottawa, 150 Louis Pasteur, Ottawa, ON, Canada K1N 6N5.
authors.forename: Valbona
authors.initials: V
authors.lastname: Celo
authors.forename: Susannah L
authors.initials: SL
authors.lastname: Scott