Counterintuitive Oxidation of Alcohols at Air–Water Interfaces

Abstract

This study shows that the oxidation of alcohols can rapidly occur at air–water interfaces. It was found that methanediols (HOCH2OH) orient at air–water interfaces with a H atom of the −CH2– group pointing toward the gaseous phase. Counterintuitively, gaseous hydroxyl radicals do not prefer to attack the exposed −CH2– group but the −OH group that forms hydrogen bonds with water molecules at the surface via a water-promoted mechanism, leading to the formation of formic acids. Compared with gaseous oxidation, the water-promoted mechanism at the air–water interface significantly lowers free-energy barriers from ∼10.7 to ∼4.3 kcal·mol–1 and therefore accelerates the formation of formic acids. The study unveils a previously overlooked source of environmental organic acids that are bound up with aerosol formation and water acidity.

Ammonolysis of Glyoxal at the Air‐Water Nanodroplet Interface

“…To determine the acceleration effect and potential contribution of the air‐water nanodroplet interface, we estimate the importance of the ammonolysis of glyoxal at the air‐water nanodroplet interface by considering the rate ratio [56,57] . The ratios r 1 , r 2 , and r 3 are written as follows: $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {r}_{1}={{{k}_{i}{\left[({\rm C}{{\rm H}{\rm O})}_{2}\right]}_{i}{\left[({\rm C}{{\rm H}}_{3}{)}_{2}{\rm N}{\rm H}\right]}_{i}}\over{{k}_{{\rm e}{\rm q}1}{k}_{2}\left[({\rm C}{{\rm H}{\rm O})}_{2}\right]\left[({\rm C}{{\rm H}}_{3}{)}_{2}{\rm N}{\rm H}\right]\left[({{\rm H}}_{2}{\rm O}{)}_{2}\right]}}\eta d\hfill\cr}}$$$ $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {r}_{2}={{{k}_{i}{\left[({\rm C}{{\rm H}{\rm O})}_{2}\right]}_{i}{\left[({\rm C}{{\rm H}}_{3}{)}_{2}{\rm N}{\rm H}\right]}_{i}}\over{{k}_{{\rm O}{\rm H}}\left[({\rm C}{{\rm H}{\rm O})}_{2}\right]\left[{\rm O}{\rm H}\right]}}\eta d\hfill\cr}}$$$ …”

“…[52][53][54][55] To determine the acceleration effect and potential contribution of the air-water nanodroplet interface, we estimate the importance of the ammonolysis of glyoxal at the air-water nanodroplet interface by considering the rate ratio. [56,57] The ratios r 1 , r 2 , and r 3 are written as follows:…”

Ammonolysis of Glyoxal at the Air‐Water Nanodroplet Interface

“…To determine the acceleration effect and potential contribution of the air‐water nanodroplet interface, we estimate the importance of the ammonolysis of glyoxal at the air‐water nanodroplet interface by considering the rate ratio [56,57] . The ratios r 1 , r 2 , and r 3 are written as follows: $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {r}_{1}={{{k}_{i}{\left[({\rm C}{{\rm H}{\rm O})}_{2}\right]}_{i}{\left[({\rm C}{{\rm H}}_{3}{)}_{2}{\rm N}{\rm H}\right]}_{i}}\over{{k}_{{\rm e}{\rm q}1}{k}_{2}\left[({\rm C}{{\rm H}{\rm O})}_{2}\right]\left[({\rm C}{{\rm H}}_{3}{)}_{2}{\rm N}{\rm H}\right]\left[({{\rm H}}_{2}{\rm O}{)}_{2}\right]}}\eta d\hfill\cr}}$$$ $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {r}_{2}={{{k}_{i}{\left[({\rm C}{{\rm H}{\rm O})}_{2}\right]}_{i}{\left[({\rm C}{{\rm H}}_{3}{)}_{2}{\rm N}{\rm H}\right]}_{i}}\over{{k}_{{\rm O}{\rm H}}\left[({\rm C}{{\rm H}{\rm O})}_{2}\right]\left[{\rm O}{\rm H}\right]}}\eta d\hfill\cr}}$$$ …”

Electrochemical Degradation of Pt3Co Nanoparticles Investigated by Off-Lattice Kinetic Monte Carlo Simulations with Machine-Learned Potentials

“…The ab initio computation of the activation barriers in electrochemical reactions is a formidable task due to the intricate nature of atomic environments and the hurdles faced when incorporating electrode potentials in the first-principles calculations (i.e., grand-canonical calculations). We note that considerable efforts are being made to tackle each of these challenges. − Additionally, advancements are also being made in directly simulating solvent environments and electrochemical reactions using MLPs. − …”