Boron trifluoride boiling point

Both boron and aluminium chlorides can be prepared by the direct combination of the elements. Boron trichloride can also be prepared by passing chlorine gas over a strongly heated mixture of boron trioxide and carbon. Like boron trifluoride, this is a covalent compound and a gas at ordinary temperature and pressure (boiling point 285 K). It reacts vigorously with water, the mechanism probably involving initial co-ordination of a water molecule (p, 152). and hydrochloric acid is obtained ... 

The product of this reaction, a Lewis acid-Lewis base complex called infonnally boron trifluoride etherate, may look unusual but it is a stable species with properties different from those of the reactants. Its boiling point (126°C) for exanple, is much higher than that of boron trifluoride—a gas with a boiling point of — 100°C—and diethyl ether, a liquid that boils at 34°C. 

Boiling-point composition curves, 7-12 Bond refractions, 1036 Boring of corks, 55, 56 Boron trifluoride, 183, 862, 864, 865 Bouveault-Blanc reduction, 247, 249, 250, 812, 832... 

Boron trifluoride butyl etherate, purchased from Fluka AG, is chosen for its convenient boiling point. 

Boron trifluoride is a colorless gas (boiling point — 100°C) with a pungent odor. 

A mixture of benzene (156 g, 2 moles) and 1-butanol (37 g, 0.5 mole) is stirred and cooled in running water under a hood while boron trifluoride is led in until 0.5 mole (34 g) has been absorbed. Phosphoric oxide (17.7 g, 0.125 mole) is then added rapidly and the mixture is slowly raised to the boiling point whilst stirring is continued. The solution becomes turbid and separates into two layers, whereupon stirring is stopped but heating is continued for a further 3 h. The upper layer is then separated, washed with aqueous alkali, and fractionally distilled, giving sec-butylbenzene (50 g, 75%), b.p. 170-172°/744 mm. 

Nitronium salts are colorless, crystalline, very stable compounds N02 BFlt decomposes at atmospheric pressure only above 170°, without subliming, into its components NO2F + BF3. The hexafluoroantimonate salts are even more stable. The higher thermal stability may be partially also a consequence of the higher boiling points of the corresponding Lewis acid fluorides compared to boron trifluoride. 

Boron trifluoride, BFj, is a colorless gas with a vapor density of 2.34, which is heavier than air. It is water-soluble and does not support combustion. It is also water-reactive, toxic by inhalation, and corrosive to skin and tissue. The TLV is 1 ppm, and the IDLH is 100 ppm in air. The boiling point is -148°F. The four-digit UN identification number is 1008. The NFPA 704 designation is health 4, flammability 0, and reactivity 1. The primary uses are as a catalyst in organic synthesis, in instruments for measuring neutron intensity, in soldering fluxes, and in gas brazing. 

---