Epoxidation of Cyclooctene Using Water as the Oxygen Atom Source at Manganese Oxide Electrocatalysts

Abstract

Epoxides are useful intermediates for the manufacture of a diverse set of chemical products. Current routes of olefin epoxidation either involve hazardous reagents or generate stoichiometric side products, leading to challenges in separation and significant waste streams. Here, we demonstrate a sustainable and safe route to epoxidize olefin substrates using water as the oxygen atom source at room temperature and ambient pressure. Manganese oxide nanoparticles (NPs) are shown to catalyze cyclooctene epoxidation with Faradaic efficiencies above 30%. Isotopic studies and detailed product analysis reveal an overall reaction in which water and cyclooctene are converted to cyclooctene oxide and hydrogen. Electrokinetic studies provide insights into the mechanism of olefin epoxidation, including an approximate first-order dependence on the substrate and water and a rate-determining step which involves the first electron transfer. We demonstrate that this new route can also achieve a cyclooctene conversion of ∼50% over 4 h.

Boosting H2 Generation Coupled with Selective Oxidation of Methanol into Value‐Added Chemical over Cobalt Hydroxide@Hydroxysulfide Nanosheets Electrocatalysts

“…Furthermore, the product of the anode is valueless O 2 , which results in a waste of electrical energy. Another strategy is to substitute the OER by relatively mild oxidation reaction with favorable thermodynamics . Along this line of thought, many soluble organic molecules that are easily oxidized, such as hydrazine, urea, amine, alcohols, furfural, 5‐hydroxymethylfurfural, pollutants, etc, have been employed to replace traditional OER.…”

Oxoiron(v) mediated selective electrochemical oxygenation of unactivated C–H and CC bonds using water as the oxygen source

“…The only example, which demonstrates the use of water as the O-atom source for epoxidation reactions has been recently reported by Manthiram and coworkers. 53 They used manganese oxide nanoparticles to catalyze cyclooctene epoxidation using water as an oxygen source with a faradaic efficiency of $30%.…”

New Redox Strategies in Organic Synthesis by Means of Electrochemistry and Photochemistry

“…Recently, Manthiram et al employed a heterogeneous catalytic approach to enable the electrochemical epoxidation of alkenes using H 2 O as the O source. 27 In this system, Mn 3 O 4 nanoparticles are deposited on the carbon anode, and electrogenerated Mn IV =O is postulated to be the active epoxidation agent. A series of linear, cyclic, and aliphatic epoxides can be attained in synthetically useful yields, thus providing a greener alternative to traditional epoxidation methods.…”