Ionic liquids based fluorination of organic compounds using electrochemical method

Abstract

Ionic liquids due to their advantageous properties gain importance in many fields. This study aims to overview the use of ionic liquids in the selective partial fluorination of organic compounds through electrochemical method. In addition to ionic liquid based fluorination, the earlier approaches of fluorination through an electrochemical process have also been highlighted. The factors such as electrode materials (Pt, Ni, and C), types of solvents (CH3CN, DMC, THF, DME, Sulfone, etc.) and type of electrolytes (Et3N·3HF, Et3NF·3HF, py·HF, etc.) which affect the electrochemical fluorination of organic compounds have been reviewed. For electrode preparation, the carbon, platinum and nickel were considered suitable materials to be used as an electrode. In CH3CN media, Et3N·3HF and Et4NF·3HF showed better efficiency during fluorination of organic compounds. Solvent play an important role in electrochemical fluorination of organic compounds, with the change of solvent the percentage yield is highly affected. Py-HF is a convenient solvent-supporting electrolyte medium with a reasonably good conductivity. The electrolyte containing solvents have some side effects on electrochemical fluorination of organic compounds as observed in cyclic voltammetric analysis. Therefore electrochemical fluorination to organic compounds without the use of solvent gained more importance. The ionic liquids have been reported for its dual properties, as solvent as well as a fluorinating agent for organic compounds in electrochemical processes. It has been concluded that solvents free electrochemical fluorination of organic compounds gives good results as compare to solvent based. Ionic liquids due to more oxidative stability were noted to have considerable effect on the yield and selectivity of organic compound fluorination.