Chemosphere 2009-11-01

Advanced oxidation and reduction process chemistry of methyl tert-butyl ether (MTBE) reaction intermediates in aqueous solution: 2-methoxy-2-methyl-propanal, 2-methoxy-2-methyl-propanol, and 2-methoxy-2-methyl-propanoic acid.

Stephen P Mezyk, D Rance Hardison, Weihua Song, Kevin E O'Shea, David M Bartels, William J Cooper

Index: Chemosphere 77(10) , 1352-7, (2009)

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Abstract

Absolute rate constants for the reaction of three important degradation products of methyl-tert-butyl ether (MTBE) with the hydroxyl radical, hydrated electron and hydrogen atom were determined in aqueous solution at room temperature. These three intermediate species; 2-methoxy-2-methyl propanal (MMP), 2-methoxy-2-methyl-propanol (MMP-OH) and 2-methoxy-2-methyl-propionic acid (MMP-acid), are formed in the degradation of MTBE under advanced oxidation and reduction process conditions. The rate constants for their hydroxyl radical oxidation of (3.99+/-0.29)x10(9), (8.02+/-0.53)x10(8), and (7.73+/-0.48)x10(8)M(-1)s(-1), respectively, show that this reaction would be the overall dominant degradation pathway for these three compounds, relative to their corresponding hydrated electron reduction values of (3.11+/-0.32)x10(7), (7.8+/-1.8)x10(6) and (1.40+/-0.10)x10(9)M(-1)s(-1), and hydrogen atom rate constants of (1.65+/-0.14)x10(7), (1.30+/-0.13) x10(8) and <1.2 x 10(6)M(-1)s(-1).