Theoretical and Experimental Study of the Product Branching in the Reaction of Acetic Acid with OH Radicals

Abstract

The product distribution of the reaction of acetic acid, CH(3)COOH, with hydroxyl radicals, OH, was studied experimentally and theoretically. Mass-spectrometric measurements at 290 K and 2 Torr of He of the CO(2) yield versus the loss of acetic acid yielded a branching fraction of 64 +/- 14% for the abstraction of the acidic hydrogen as follows: CH(3)COOH + OH --> CH(3)COO + H(2)O --> CH(3) + CO(2) + H(2)O. A quantum chemical and theoretical kinetic analysis showed that the abstraction of the acidic hydrogen is enhanced relative to the abstraction of -CH(3) hydrogens because of the formation of a strong pre-reactive H-bonded complex, where the H-bonds are retained in the H-abstraction transition state. The potential energy surface of the reaction is explored in detail, and the reaction products of the individual channels are identified. The theoretical product branching is found to be critically dependent on the energetic and rovibrational differences between the H-abstraction transition states.

Decomposition of Acetic Acid Using Multiple Bubble Jets with Pulsed Electrical Discharge

“…Then, the OH radicals decompose CH 3 COOH molecules completely to CO 2 and H 2 O as shown in Eq. (7) [4,8].…”

“…The obtained decomposed CH 3 COOH concentration was the minimum at f = 800 Hz with an unstable discharge in a bubble, but increased at f = 1,000 and 1,200 Hz. However, the energy efficiency decreased gradually with applied frequency because of the recombination of OH radicals for given input electric power [8]. Figure 13 shows the concentration of decomposed CH 3 COOH and energy efficiency with the flow rate at V = 6 kV, f = 1,000 Hz, and a duty ratio of 10 % after the 120 min treatment.…”

“…In this study, a novel multiple Ar bubble jet system encapsulating and diffusing O and OH radicals generated by a pulsed electrical discharge inside and outside of small gas bubbles, respectively, was successfully constructed Nishiyama et al [7] and investigated for the decomposition of acetic acid (CH 3 COOH) as a model persistent harmful pollutant [8].…”

Degradation of Acetic Acid in Water Using Gas-Liquid Plasma with SPG Membrane

“…H 2 O 2 are widely used as an indicator of OH radical production because the recombination reaction of OH radical into H 2 O 2 is a main quenching reaction [16]. OH radicals could react with acetic acid and decompose it to CO 2 as described in the reaction (2) [17]. We evaluated the degradation effect of acetic acid by the TOC (total organic carbon) measurement.…”

Catalyst Effect on Degradation of Organism by Nanoseconds Pulsed Discharge in Gas-Liquid Mixture

“…Therefore the production of H 2 O 2 was used to evaluate the generation of OH radicals. A part of OH radicals would react with acetic acid and decompose it as described in the reaction (2) [7]. We evaluated the degradation effect of acetic acid by the TOC measurement.…”