Electrosynthesis of Carboxylic Acids by Indirect Electrocatalytic Oxidation of Aliphatic Alcohols with the Participation of Reactive Oxygen Species
V. L. KORNIENKO1, A. M. KOSHELEVA1, G. V. KORNIENKO2
1Institute of Chemistry and Chemical Technology, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, Russia
2Siberian State Technological University, Krasnoyarsk, Russia
Keywords: электросинтез, алифатические спирты, карбоновые кислоты, оксидогидроксидный никелевый электрод, допированный бором алмазный электрод, выход по току, выход по веществу, electrosynthesis, aliphatic alcohols, carboxylic acids, nickel oxide-hydroxide electrode, boron-doped diamond electrode, yield by current, yield by substance
Abstract
The electrosynthesis process of carboxylic acids (butyric, caproic, pelargonic, and capric) by indirect electrocatalytic oxidation of aliphatic alcohols (1-buthanol, 1-hexanol, 1-nonanol and 1-decanol) with the participation of reactive oxygen species (ROS). The process was performed using three schemes of ROS generation: 1) oxidation at the anode (anodic); 2) oxidation at the anode with the addition of H2O2 to the electrolyte (anode + H2O2); 3) paired electrolysis - oxidation at the anode with concurrent generation of carbon-graphite cathode while passing oxygen through the electrolyte solution. It was found that when using as the anode oxyhydroxide nickel electrode the most effective scheme of oxidation of aliphatic alcohols was the paired electrosynthesis: at the pushed quantity of electricity Q / Q theor = 0.14, the yield of acids by current amounted to 168 % for oil and 148 % for caproic acid; Q / Q theor = 1.0 output capric acid was 64 %. On boron-doped diamond electrode, further generation of reactive oxygen species leads to a decrease of the yield of the target product due to its further oxidation, therefore, indirect anodic oxidation is optimal to apply: when Q / Q theor = 1.0, the yield by current of pelargonic acid is equal to 89 %. It was concluded that for complex optimization of the electrolysis process, the electrosynthesis method of carboxylic acids by indirect electrocatalytic oxidation of aliphatic alcohols could be considered as an alternative to the existing.
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