A new approach for epoxidation of fatty acids by a paired electrosynthesis

•Epoxides were prepared by an electrochemical method.•Epoxides were obtained in two compartments by paired electrosynthesis.•Fatty acids were epoxidized by peroxyformic acid generated in situ in the catholyte.•Fatty acids were epoxidized by hypochlorous acid generated in situ in the anolyte.•New green methods of normal temperature, atmospheric pressure and energy saving.

This paper reports a novel and effective electrochemical method to prepare epoxides using a paired electrosynthesis. The electrochemical epoxidation of unsaturated fatty acids by HCOOOH generated in situ from H2O2 (by oxygen reduction) and HCOOH in the catholyte, and by HOCl also generated in situ in the anolyte by oxidation of chloride ions was studied using HCl as a catalyst. The FTIR spectra of the epoxidised castor oil, soybean oil, and corn oil were compared to those of the parent unreacted oils. The highest relative epoxy yield of castor oil (40%) was achieved at 25 °C and pH 6.5 after 3 h, and the epoxy value of castor oil reached 0.12 mol/100 g. The optimal passing oxygen rate, molar ratio of castor oil double bonds to HCOOH and current density were determined to be 3 cm3 s− 1, 8 and 0.3 A cm− 2, respectively.

Graphical abstractThe epoxides were prepared from unsaturated fatty acids by peroxyformic acid generated in situ from hydrogen peroxide (by oxygen reduction) and formic acid in the catholyte, and by hypochlorous acid also generated in situ in the anolyte by oxidation of chloride ions with a paired electrosynthesis.Figure optionsDownload full-size imageDownload as PowerPoint slide