Hydrolysis of tert-butyl methyl ether the (MTBE) in dilute aqueous acid

Citation
Kt. O'Reilly et al., Hydrolysis of tert-butyl methyl ether the (MTBE) in dilute aqueous acid, ENV SCI TEC, 35(19), 2001, pp. 3954-3961
Citations number
68
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Environment/Ecology,"Environmental Engineering & Energy
Journal title
ENVIRONMENTAL SCIENCE & TECHNOLOGY
ISSN journal
0013-936X → ACNP
Volume
35
Issue
19
Year of publication
2001
Pages
3954 - 3961
Database
ISI
SICI code
0013-936X(20011001)35:19<3954:HOTMET>2.0.ZU;2-6
Abstract
tert-Butyl methyl ether (MTBE) is generally considered to be resistant to c hemical transformation in aqueous solution. This lack of reactivity has led to concerns of the longterm impacts of MTBE in groundwater. Although hydro lysis in the presence of strong acids has been recognized as a mechanism fo r MTBE transformation, it has been discounted as a significant reaction und er environmental conditions. In this study, we have examined the fate of MT BE and other ether oxygenates under moderately acidic conditions (greater t han or equal to pH 1). The results demonstrate that MTBE is sensitive to ac id-catalyzed hydrolysis reaction that generates tert-butyl alcohol (TBA) an d methanol as products. The reaction is first-order with respect to the con centration of MTBE and hydronium ion with a second-order rate constant of a bout 0.9 x 10(-2) M-1 h(-1) at 26 degreesC. Commercially available acidic i on-exchange resins were also shown to catalyze the hydrolysis of MTBE at ne ar neutral pH. Pseudo first-order rate constants were observed to be as hig h as 0.03 h(-1) at 25 degreesC and 0.12 h(-1) at 35 degreesC. These finding s are discussed in terms of their possible implications for the treatment a nd environmental fate of MTBE and other gasoline oxygenates.