Inorganics - Ammonia Borane Chemistry
Ammonia Borane – a Novel Chemical Reinvention ?
It’s not often that five decades pass between the original development of a chemical preparation and the progression of its unique product into advanced chemical technologies. This would appear to accurately describe the renewed interest in ammonia borane, a molecule that is so hydrogen-rich that it has invited scrutiny in fields of study ranging from selective reductions in organic synthesis to fuel cell technologies driven by the in situ generation of molecular hydrogen.
It was not until 1980 that one of the most definitive papers on the synthetic utility of amine borane reagents in the reduction of aldehydes and ketones was published (Andrews and Crawford, Pfizer Inc., Tetrahedron Letters, Volume 21, pp. 693-696); more recently, continuing interest in the optimization of borohydride reductions was reflected in a paper published by Zeynizadeh and Behyar that described the use of wet THF as solvent in mild reductions involving sodium borohydride (Bull. Chem. Soc. Jpn., 78, 307-315 (2005)).
The deceptively simple formulation of ammonia borane – H3NBH3 – belies the years of difficulties encountered in making the material until its successful synthesis was reported as part of thesis research work done by Dr. Sheldon G. Shore, who has maintained an active interest in boron hydride chemistry (as well as many other novel chemistries) for fifty years.
In particular, GFS anticipates successful development of production quantities of very high quality ammonia borane for use as an alternative to common borohydride salts in both traditional and unusual organic reductions. Areas of interest are expected to include:
- Reactions that give unusually favorable yields or unexpected results because of the hydrolytic stability of ammonia borane and its solubility in both protic and aprotic solvents.
- Reactions sensitive to the presence of cationic impurities such as sodium or potassium.
- Reactions where reagent purity, handling convenience, and process work-up are critical factors.
The ammonia borane produced by the process developed by Dr. Shore compares most favorably to material available from other processes:
- Purity in excess of 99%, low in carbon and other salt residues
- White, fine, free-flowing powder with long-term stability
- Free of organic residues and essentially odor-free
- Potential availability of multiple grades of material tailored to specific applications
Additional information on the properties, uses, and availability of ammonia borane is available from GFS. Please contact jrlong@gfschemicals.com.
Inorganics - Ammonia Borane Chemistry
