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

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) × 109, (8.02 ± 0.53) × 108, and (7.73 ± 0.48) × 108 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) × 107, (7.8 ± 1.8) × 106 and (1.40 ± 0.10) × 109 M−1 s−1, and hydrogen atom rate constants of (1.65 ± 0.14) × 107, (1.30 ± 0.13) × 108 and < 1.2 × 106 M−1 s−1.