Process for the Fluorination of Boron Hydrides

Abstract

A process for fluorination of borohydride salts including providing a reaction medium comprising HF and a superacid. A borohydride salt compound is added to the reaction medium. The borohydride salt is reacted with the with the reaction medium under conditions to form a fluorinated borohydride salt. In addition, reactor vessels may be provided for reacting the HF, superacid additive and borohydride that are fabricated from materials resistant to superacid compositions.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The subject matter of this invention is related to U.S. patent application Ser. Nos. 10 / 655,476, filed on Sep. 4, 2003; 10 / 924,293, filed on Aug. 23, 2004; 11 / 372,907, filed on Mar. 10, 2006, and 11 / 197,478, filed on Aug. 5, 2005. The disclosure of the previously identified patent applications is hereby incorporated by reference.[0002]The present invention is directed to methods for fluorinating boron hydride compounds.BACKGROUND OF THE INVENTION[0003]Fluorinated boron hydride anions are weakly coordinating anions and have been used as electrolytes and as catalytic components, particularly to enhance the catalytic activity of metal cations finding use in a variety of reactions.[0004]The substitution of borohydrides, including polyhedral closo-boranes and closo-carboranes with fluorine to various degrees has previously been afforded by employing a number of methods. For example, the direct fluorination of these exemplary boron hydrides wit...

AI Technical Summary

Benefits of technology

[0018]An advantage of the present invention includes selective and controlled fluorination of borohydrides with facile, high-yielding synthesis of fluorinated boron compounds of narrow and controlled degrees of fluorination under reaction conditions that are industrially practicable.

[0019]Another advantage of the present invention includes an ability to achieve high levels of fluorination of the borohydride anions.

[0020]Still another advantage of the present invention includes an ability to achieve higher yields and reaction efficiency.

[0021]Still another advantage of the present invention includes an ability to achieve high loadings of reactant in the carrier, and an ability to minimize yield loss due to byproduct formation.

Problems solved by technology

N—F fluorinating agents suffer from the drawback that they are often accompanied by difficulties associated with impurities formed by the participation and undesirable substitution of the solvent.

The fluorination methods listed above, while capable of providing partially fluorinated products, all suffer from the drawback that they typically produce mixtures of products with various isomers and relatively wide ranges of degrees of fluorination.

These conditions are undesirable for industrial processes because the critical temperature for HF is 188° C. Such high temperature HF is damaging to equipment and dangerous to handle.

The temperatures utilized by this process are undesirably high in that the temperatures are above the critical temperature for HF.

This process suffers from the drawback that the distribution of fluorinated products is undersirably broad.

In addition, the process utilizes expensive reagents, such as F2.

The reaction when conducted in the presence of water was difficult to run to completion as evidenced by the use of a 5-fold excess of fluorine.

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