Safety boron hydrides

Diborane(6), B2H. This spontaneously flammable gas is consumed primarily by the electronics industry as a dopant in the production of siHcon wafers for use in semiconductors. It is also used to produce amine boranes and the higher boron hydrides. Gallery Chemical Co., a division of Mine Safety AppHances Co., and Voltaix, Inc., are the main U.S. producers of this substance. Several hundred thousand pounds were manufactured worldwide in 1990. 

Safety considerations are paramount in any boron hydride synthesis. The energy yield from the oxidations of boron hydrides is too high for any cavalier treatment of boron hydrides. Exclusion of air is the critical consideration in diborane reactions. Decaborane(14) is less reactive, generally, in a kinetic sense, but the thermodynamic potential is comparable. In addition, all volatile boron hydrides are toxic. The procedures described in the latter two preparations are within our experience non-hazardous. These procedures should be followed in every detail improvisation is not recommended. 

Manufacturing Chemists Association Chemical Safety Data Sheet SD-84, Boron Hydrides, pp 5-18. Washington, DC, Manufacturing Chemists Association, 1961... 

Diborane in air may be analyzed by passing air through a PTFE filter and oxidizer-impregnated charcoal. It is oxidized to boron and desorbed with 3% H2O2. Boron is measured by plasma emission spectrometry or ICP emission spectrometry (NIOSH. 1984. Manual of Analytical Methods, 3rd ed. Cincinnati, OH National Institute for Occupational Safety and Health). Boron hydrides can be analyzed by FTIR techniques. 

SAFETY PROFILE Stable in dry air at room temperature. It decomposes above 125° forming Al, H2, and lithium hydride. Very powerful reducer. Can ignite if pulverized even in a dry box. Reacts violendy with air, acids, alcohols, benzoyl peroxide, boron trifluoride etherate, (2-chloromethyl furan + ethyl acetate), diethylene glycol dimethyl ether, diethyl ether, 1,2-dimethoxyethane, dimethyl ether, methyl ethyl ether, (nitriles + H2O), perfiuorosuccinamide,... 

SAFETY PROFILE Poison by ingestion, inhalation, and skin contact. Flammable can liberate H2. Incompatible with H2O as moisture on fibers of cellulose or as liquid. See also LITHIUM, BORON COMPOUNDS, and HYDRIDES. 

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