Title: Potassium Borohydride
CAS Registry Number: 13762-51-1
CAS Name: Potassium tetrahydroborate
Molecular Formula: BH4K
Molecular Weight: 53.94
Percent Composition: B 20.04%, H 7.47%, K 72.48%
Line Formula: KBH4
Literature References: Prepn: H. I. Schlesinger et al., J. Am. Chem. Soc. 75, 199 (1953). Commercial process: M. D. Banus et al., ibid. 76, 3848 (1954). NMR relaxation study: T. Tsang, T. C. Farrar, J. Chem. Phys. 50, 3498 (1969); IR and Raman spectra: K. B. Harvey, N. R. McQuaker, Can. J. Chem. 49, 3272 (1971). Use as reducing agent in protein labelling: E. K. J. Pauwels et al., Nucl. Med. Biol. 20, 825 (1993); in simple reductions: C. Than et al., J. Labelled Compd. Radiopharm. 38, 693 (1996); J. C. Briggs et al., Tetrahedron 53, 3943 (1997). Review of potassium and other metal tetrahydroborates: B. D. James, M. G. H. Wallbridge, Prog. Inorg. Chem. 11, 99-231 (1970).
Properties: Non-hygroscopic crystals. Stable to air. d 1.11. nD 1.490. Dec commences at about 500°. Supports combustion. Negative heat of soln in H2O = 6.3 kcal/mol. Soly (w/w) in water at 25°: 19%; liq ammonia at 25°: 20%; ethylenediamine at 75°: 3.9%; methanol at 20°: 0.7%; DMF at 20°: 15.0%. 0.25 g dissolves in 100 g of 95% ethanol at 25°. Soly in a 4:1 water-methanol mixture: 13 g/100 g. Insol (< 0.01%) in isopropylamine, benzene, hexane, ether, dioxane, tetrahydrofuran and acetonitrile. Alkaline aq solutions are stable.
Index of refraction: nD 1.490
Density: d 1.11
Use: Reducing agent; source of H-. |