54271-60-2Relevant academic research and scientific papers
Studies on the interaction of selenite and selenium with sulphur donors. Part 2. A kinetic study of the reaction with 2-mercaptoethanol
Amaratunga, Wimal,Milne, John
, p. 2506 - 2515 (2007/10/02)
Selenous acid is reduced by 2-mercaptoethanol in water to elemental selenium in two stages. H2SeO3 + 4HOC2H4SH -> HOC2H4SSeSC2H4OH + HOC2H4SSC2H4OH + 3H3O HOC2H4SSeSC2H4OH -> Se + HOC2H4SSC2H4OH The reaction have been followed by spectrophotometry and by proton and 77Se NMR spectroscopy.The mechanism of the first stage parallels that proposed for butyl thiols in 60percent dioxane but nucleophilic attack by RS- rather than RSH on the Se(IV) intermediate, RSSeO2-, is of greater signi ficance for 2-mercaptoethanol than for n-butylthiol.The signals of three intermediates are observed in the Se-77 NMR spectra of a mixture undergoing the first reaction stage.These arise from HOC2H4SSeO2-, (HOC2H4S)2SeO, and an asymmetric intermediate that chemical shift evidence suggests is the sulfinic acid ester, HOC2H4S(O)SeSC2H4OH.The second stage involves coordination of the bis(thio)selenide by thiolate followed by decomposition to disulfide and selenium.Evidence is presented to support a reaction mechanism involving nucleophilic attack exclusively at Se(II) and not at S(II) as suggested in previous work.This stage is strongly accelerated at basic pH and, at pH 8.3 and above, both the first and second stages can take place simultaneously.
