Anodic oxidation of alkane carboxylates and perfluoroalkane carboxylates at platinum and graphite anodes: product selectivity and mechanistic aspects

Abstract

Constant current electrolysis of sodium octanoate produced Kolbe and non-Kolbe products. Dimer is the major product at Pt anode and non-Kolbe products were formed on graphite anode. Influence of quantity of electricity, current density, and nature of electrode was studied. Under optimized experimental conditions, butanoate, perfluorooctanoate, and perfluorobutanoate were electrolyzed. Major and minor products were identified based on GC-MS spectra. Isomeric products are due to cationic rearrangement by 1,2-hydride shift and selectivity among them are also rationalized. Anodic decarboxylation of perfluorobutanoate and perfluorooctanoates gave Kolbe dimer on platinum electrode. The role of solvent and criteria for choice of radical or cationic pathway has been discussed.

(Non-)Kolbe electrolysis in biomass valorization – a discussion of potential applications

“…21 The group of Noel screened different alkane-and perfluoroalkane carboxylates for (Non-)Kolbe electrolysis. 102 The authors also tested sodium butanoate over graphite and Pt electrodes in aqueous methanol (40 vol%). However, they could not identify the side product in both cases and only obtained Non-Kolbe products mainly 3-and 1-propyl butyrate (10% and 24% selectivity for Pt and 10% and 20% selectivity for graphite).…”

“…Interestingly, this trend was not observed for perfluorooctanoic acid, where only the dimer was formed. 102 A novel compound was synthesised via the Kolbe mechanism starting from levulinic acid. Besides the coupling product 2,7-octanedione, also an increased formation of 3-buten-2-one was observed which led to the formation of 5-acetyl-2,9-decanedione.…”

Decarboxylation‐Initiated Intermolecular Carbon‐Heteroatom Bond Formation

“…This reaction concept was consequently extended to other nucleophiles. The carbocationic intermediates were successfully intercepted by alcohols, [60–95] carboxylic acids, [87,96,97] nitriles, [98–101] and nitrate [102,103] to give ether, ester, amides, and nitrate esters, respectively. Such transformation has become known as the Hofer‐Moest reaction [104–108] .…”

The Synthesis of Hydrocarbons for Fuel and Lubricants via Ceramic Membrane Reactor

“…One approach reported in the literature to address the limitations of methanol is the use of a mixture of water and methanol (termed methanolic solutions), which hinders the formation of methyl esters, improves the conductivity, and reduces the amount of water splitting and methanol degradation (5). Experiments have shown that methanolic solutions work well for the smaller sodium carboxylates, but the solubility of the C 12 and larger salts dramatically decreases with size.…”