Nomenclature
CAS number: 19287-45-7
Boroethane; diboron hexahydride.
B
2H
6; mol wt 27.67.
B 78.14%, H 21.86%.
Description and references
Review of methods of prepn: Adams in Borax to Boranes, Advances Chem. Ser. No. 32 (American Chemical Society, 1961) pp 60-68. Review
of structure and properties: Campell, Jr. in Progress in Boron Chemistry vol. 1, Steinberg,
McCloskey, Eds. (Macmillan, New York, 1964) pp 167-184. Reviews of
reaction chemistry: Schenker, Angew. Chem. 73, 81-107 (1961); Long in Adv.
Inorg. Chem. Radiochem. 16, 201-296 (1974).
Review of toxicity: see Decaborane(14). General reviews: Stock, Hydrides of Boron
and Silicon (Cornell Univ. Press, Ithaca, 1933), passim; Siegel, Mack, J. Chem. Educ. 34, 314-317 (1957); Major, Chem.
Eng. Prog. 54(3), 49-54 (1958); Mikhailov, Usp. Khim. 31, 417-451 (1962); Russian Chem. Rev. (Eng. Ed.) 31, 224-235 (1962); Adams, Boron, Metallo-Boron
Compounds and Boranes (Interscience, New York, 1964) pp
555-605; Lipscomb, Boron Hydrides (Benjamin, New York, 1963) passim; Long, Prog. Inorg. Chem. 15, 1-99 (1972);
Greenwood in Comprehensive Inorganic Chemistry vol. 1, J. C. Bailar, Jr., et al., Eds. (Pergamon
Press, Oxford, 1973) pp 763-783.
Properties
Colorless, flammable gas; repulsive, sickly-sweet
odor. mp -165°; bp -92.5°. d-112 0.447; d-29.6 0.33; d15.0 0.210. Critical temp
16.7°; critical press. 39.5 atm; Cp at 25°: 13.60 cal/mole/°C. Dec
at red heat to B + H2, at lower temps to H2 and
other boron hydrides. Spontaneous ignition temp in air about 40-50°;
presence of contaminants may lower the temp limit so that ignition
or detonation of diborane(6)-air mixtures may occur at or below room
temp. Hydrolyzes in water to H2 + H3BO3. Sol in CS2. Reacts with NH3 to form
diborane diammoniate; reacts slowly with Br2 and explosively
with Cl2 to form boron halides; reacts with hydrocarbons
or organoboron compds to give alkyl- or arylboron compds; reacts with
metal alkyls to form metal borohydrides; reacts with strong electron
pair donors to form borane addn compds.Caution
Potential symptoms of overexposure
are tightening of chest, precordial pain, shortness of breath, nonproductive
cough and nausea; headache, lightheadedness, vertigo, chills, fever,
fatigue, weakness, tremor and muscle fasciculation. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 92. 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 2987, 2990-2992.Use
As catalyst for olefin polymerization; as rubber
vulcanizer; as reducing agent; as flame-speed accelerator; in rocket
propellants; in intermediate in prepn of the boron hydrides; in conversion
of olefins to trialkylboranes and primary alcohols; as a doping gas.