Fluorination of Thermodynamically Unstable Nickel Fluorides using NiF₆^2- Salts

IB-1216

E.O. Lawrence Berkeley National Laboratory

APPLICATION OF TECHNOLOGY:

• Used in conjunction with the Simons electrochemical fluorination (ECF) method, would bring about enhanced efficiency of fluorination of bulk chemicals
• Particularly attractive for fluorination of costly, low-volatility and low-solubility (in aHF) organic compounds that are less amenable to the ECF method in general use at this time

ADVANTAGES:

• Reactions take place at or below room temperature
• Most of the hydrogen atoms in organic molecules are replaced quickly and cleanly
• Oxidant, unlike elemental fluorine, is also effective in fluorinating cationic species
• Procedure uses only the required amount of oxidant in a one-container procedure, generates the perfluorinated compound free of underfluorinated products, and produces the perfluorinated product in essentially quantitative yield

ABSTRACT:

Berkeley Lab researchers have devised a series of simple, controlled reactions, which take place at or below room temperature, by which hydrogen is substituted by fluorine in organic compounds. Berkeley Lab’s new fluorination reactions are carried out in liquid anhydrous hydrogen fluoride (aHF), which is easily and quantitatively recovered. Most of the hydrogen atoms in organic molecules are replaced quickly and cleanly by simply using a solution of a NiF₆^2- salt for the oxidation of H to F. Solubility of an organic compound in aHF is not necessary for efficient fluorination, since NiF₆^2- effectively carries the oxidizer to insoluble compounds. This oxidant, unlike elemental fluorine, is also effective in fluorinating cationic species. Only hydrogen atoms at tertiary carbon sites in highly fluorinated molecules require the more powerful oxidizers, NiF₄ and NiF₃, for their oxidation. These binary fluorides are generated from the NiF₆^2- salts using boron trifluoride, BF₃. Berkeley Lab’s new approach to fluorination uses only the required amount of oxidant in a one-container procedure, generates the perfluorinated compound free of underfluorinated products, and produces the perfluorinated product in essentially quantitative yield. This new process is particularly attractive for the fluorination of costly, low-volatility and low-solubility (in aHF) organic compounds that are less amenable to the Simons electrochemical fluorination (ECF) method in general use at this time. In addition, use of Berkeley Lab’s new process in conjunction with the ECF method would bring about enhanced efficiency of fluorination of bulk chemicals.

STATUS: U.S. Patent #6,160,158. Available for licensing

REFERENCE NUMBER: IB-1216