Nomenclature
CAS number: 7637-07-2
BF
3; mol wt 67.81.
B 15.94%, F 84.05%.
Description and references
A strong Lewis acid. Prepn: Swinehart, US 2148514, US 2196907 (1939, 1940 both to Harshaw Chemical); Booth, Wilson, Inorg. Synth. 1, 21 (1939); Kwasnik
in Handbook of Preparative Inorganic Chemistry Vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd
ed., 1963) pp 219-222; Wiesboeck, US 3690821 (1972 to U.S. Steel). Dihydrate:
McGrath et al., J. Am. Chem. Soc. 66, 1263 (1944). Reviews: Booth, Martin, Boron Trifluoride and Its Derivatives (John
Wiley & Sons, 1949), 296 pp; Booth in Fluorine Chemistry Vol. 1, J. Simons, Ed.
(Academic Press, New York, 1950) pp 201-224; Topchiev et al., Boron Fluoride and Its Compounds as Catalysts
in Organic Chemistry (Pergamon Press, 1959) 326 pp; Martin
in Kirk-Othmer Encyclopedia of Chemical Technology Vol. 9 (Interscience, New York, 2nd ed., 1966) pp 554-562;
Massey, Adv. Inorg. Chem. Radiochem. 10, 1-152 (1967). Review of toxicology and human exposure:
Toxicological Profile for Boron (PB93-110674, 1992) 110 pp.
Properties
Colorless gas. Pungent, suffocating odor. Forms
dense white fumes in moist air. bp 127.1°. bp 100.4°. d4 (100.4°; liq) 1.57. d (gas at STP) 3.07666 g/l. Poisonous. Soly in water (0°): 332 g/100 g; some hydrolysis occurs to form
fluoboric and boric acids. Soly in anhydrous H2SO4: 1.94 g/100 g acid. Forms solid complex with nitric acid
(HNO3.2BF3). Sol in most saturated and halogenated
hydrocarbons and in aromatic compds. Polymerizes unsaturated molecules.
Easily forms coordination complexes with molecules having at least
one unshared pair of electrons. Reacts with incandescence when heated
with alkali metals or alkaline earth metals except magnesium.Caution
Potential symptoms of overexposure
are irritation of eyes, skin, nose, respiratory system; epistaxis;
burns to eyes and skin. See NIOSH
Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997)
p 32. See also Patty's Industrial
Hygiene and Toxicology vol. 2B, G. D. Clayton,
F. E. Clayton, Eds. (Wiley-Interscience, New York, 3rd ed., 1981)
pp 2996-2999.Use
To protect molten magnesium and its alloys from
oxidation; as a flux for soldering magnesium; as a fumigant; in ionization
chambers for the detection of weak neutrons. By far the largest application
of boron trifluoride is in catalysis with and without promoting agents.