방향족 아민류 안정제를 이용한 펜톤 유사반응의 과산화수소 분해 경향성 연구

Abstract

Hydrogen peroxide was widely used oxidizer due to its strong oxidative power. However, its decomposition rate was too fast to handle for the industrial applications like pulp bleaching, advance oxidation process, or pickling process. Therefore, a stabilizer to decelerate the reaction of hydrogen peroxide decomposition was needed. There were two types of stabilizer: chelators, and radical scavengers, which was more efficient for using in sufficient condition for hydrogen peroxide. For the first time, a screening test for potential stabilizers was carried out on an attempt to decelerate hydrogen peroxide decomposition for the guarantee of continuous pickling process. Among all 52 radical scavengers, 2-anilinoethanol (AE) and phenoxyethanol (PE) successfully enlarged half -life of peroxide. Another screening test for potential stabilizers was carried out to apply them in the other industrial conditions. 2-anilinoethanol and phenoxyethanol was compared with chelator type stabilizers and they showed superb stabilizing efficiency in pH 4. Those two stabilizers indicated better stabilizing effect in other pH, temperature, concentration of initial hydrogen peroxide, concentrations of initial stabilizers, kind of anions, and kinds of metal cations. 2-Anilinoethanol showed better stabilizing effect on decelerating the decomposition of hydrogen peroxide than phenoxyethanol, but the Fenton-like reaction was very fast and complex for elucidating the interactions among many kinds of radical species, then I calculated Gibbs free energy of reaction and Gibbs free energy of activation by DFT method. All of possible scavenging mechanisms were modeled by Dmol3 program in Materials Studio 7.0 package, also calculated geometry optimization and frequency calculations. Hydrogen atom transfer (HAT) reaction which generated water molecule was the main pathway to catch OH radicals. In the structure of 2-anilinoethanol, there was a nitrogen atom which had a hydrogen atom, and the OH radical could attack this site with ease. By using the 2-anilinoethanol and its similar structure, we could control the rate of hydrogen peroxide decomposition without overreacting.