Selective Chloride-Mediated Neat Ethanol Oxidation to 1,1-Diethoxyethane via an Electrochemically Generated Ethyl Hypochlorite Intermediate

Abstract

Selective primary alcohol oxidation to form aldehydes products without overoxidation to carboxylic acids remains a key chemistry challenge. Using simple alkylammonium chloride as the electrolyte with a glassy carbon working electrode in neat ethanol solvent, 1,1-diethoxyethane (DEE) was prepared with >95% faradaic efficiency (FE). DEE serves as a storage platform protecting acetaldehyde from overoxidation and volatilization. UV–vis spectroscopy shows that the reaction proceeds through an ethyl hypochlorite intermediate as the sole chloride oxidation product, and that this intermediate decomposes unimolecularly (rate constant k = (6.896 ± 0.516) × 10–4 s–1) to form HCl catalyst and acetaldehyde, which undergoes rapid nucleophilic attack by ethanol solvent to form the DEE product. This indirect oxidation mechanism enables ethanol oxidation at much less positive potentials due to the fast kinetics for chloride anion oxidation.

Phase Engineering of Molybdenum Carbide/Oxide for Highly‐Efficient Electrocatalytic Hydrogen Production

“…The continuous consumption of fossil energy not only leads to the depletion of energy, but also causes serious pollution to the environment, and brings adverse effects on social development and people's lives. [1][2][3][4] Therefore, it is the goal of mankind all over the world to develop efficient, clean and economical energy sources, [5] and it is of great significance to achieve carbon peak and carbon neutralization. Hydrogen energy is considered as one of the ideal clean energy sources to replace fossil fuels due to its high energy density, renewability, and environment friendly.…”

“…Fossil fuels are the main energy source for human society. The continuous consumption of fossil energy not only leads to the depletion of energy, but also causes serious pollution to the environment, and brings adverse effects on social development and people‘s lives [1–4] . Therefore, it is the goal of mankind all over the world to develop efficient, clean and economical energy sources, [5] and it is of great significance to achieve carbon peak and carbon neutralization.…”

Atomically Dispersed Pt on CdS Nanosheets for Photocatalytic Evolution of H2 and 1,1-Diethoxyethane from Ethanol

“…As a zero-emission carrier with energy density of 142 MJ kg –1 , H 2 is believed to be an effective chemical energy carrier that could be produced from renewable sources, for example, via photo/electro-catalysis H 2 evolution reaction. – Ethanol, derived from biomass fermentation, contains 13.04 wt % of hydrogen, making it an ideal chemical hydrogen source. Furthermore, it is also a versatile precursor for producing numerous chemicals and fuels, including acetaldehyde, acetic acid, esters, and acetals. – Among them, 1,1-diethoxyethane (DEE) is a significant ethanol product owing to its wide applications in fuel additives, pharmaceuticals, chemical synthesis, and so on. – Hence, ethanol is an appropriate platform for H 2 production concurrently with high value-added conversion.…”

Electrochemical Ethylene Oxide Synthesis from Ethanol

“…15 Recently, the selective chlorination of neat ethanol to ethyl hypochlorite via an indirect oxidation method using a glassy carbon working electrode has been reported. 16 However, this approach also did not produce 2-chloroethanol. These studies highlight the difficulty of selectively oxidizing ethanol to the desired chlorohydrin and the promise of halide-mediated reaction pathways.…”

“…Similarly, the strong oxidative potentials required for chlorination on most electrocatalyst materials result in overoxidized products, including CO 2 , in the complete oxidation of ethanol . Recently, the selective chlorination of neat ethanol to ethyl hypochlorite via an indirect oxidation method using a glassy carbon working electrode has been reported . However, this approach also did not produce 2-chloroethanol.…”