Decaborane oxidation

The explosion limits for decaborane-02 mixtures were reported by Bauer and Wiberly. For a 22/1 [02]/[BioHi4] mixture, the lower explosion limit was at 85 torn The second explosion limit extended from 100-114 torr over a temperature range from 78-112 C. At pressures greater than 114 torr, explosion occurred below 80 °C. Addition of N2 decreased the temperature necessary for explosion at a given total pressure the second explosion limit was raised at any temperature between 80 and 120 °C. 

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This sequence of reactions is a useful route to the pure element, but more complex boranes form when the heating is less severe. When diborane is heated to 100°C, for instance, it forms decaborane, B]0H14, a solid that melts at 100°C. Decaborane is stable in air, is oxidized by water only slowly, and is an example of the general rule that heavier boranes are less flammable than boranes of low molar mass. 

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. 

Copper(II) sulfate Cumene hydroperoxide Cyanides Cyclohexanol Cyclohexanone Decaborane-14 Diazomethane 1,1-Dichloroethylene Dimethylformamide Hydroxylamine, magnesium Acids (inorganic or organic) Acids, water or steam, fluorine, magnesium, nitric acid and nitrates, nitrites Oxidants Hydrogen peroxide, nitric acid Dimethyl sulfoxide, ethers, halocarbons Alkali metals, calcium sulfate Air, chlorotrifluoroethylene, ozone, perchloryl fluoride Halocarbons, inorganic and organic nitrates, bromine, chromium(VI) oxide, aluminum trimethyl, phosphorus trioxide... 

Boranes oxidize in air to form boron oxides. Diborane spontaneously ignites in air around 50°C. The presence of impurities can lower the ignition temperature. Tetraborane decomposes slowly at ordinary temperatures but rapidly on heating. Decaborane is very stable at ordinary temperatures. When heated at 300°C, it slowly decomposes to boron and hydrogen. All boranes decompose to their elements at elevated temperatures. 

Decaborane dianion, oxidative coupling, 26 73 Decaboron decahalides, 26 13, 48 hydrogenation of chloride, 26 48 pyrolysis of dianions, 26 48 Decabromotriselenate(lI,IV), 35 290 Decadiene complexes with silver, 12 340 Decaholotellurate(IV), structure, 35 249-251 Decarbonylation, thermal, of trifluoroacetyl derivatives, 27 295-300... 

Dicarbadodecaborane, preparation and structure of, 5 342-343 Dicarbomethoxy acetylene, 45 48, 49 Dicarbon decaboranes, 26 85 base degradation, 26 90 bonding, 26 62 dianions, 26 78-79 reaction with Lewis bases, 26 85 1,2-Dicarbonic acid dichlorides, 33 300 Dicarbon nonaborane anion, oxidative coupling, 26 73... 

Pentaborane Diborane Decaborane Sodium borate Boron trifluoride Calcium borate Boron tribromide Boron oxide Total dust Respirable fraction Sodium tetraborate Decahydrate... 

Bis(cyclopentadienyl)bis(pentafluorophenyl)zirconium, 3824 Bis(cyclopentadienyldinitrosylchromium), 3269 Bis(cyclopentadienyl)hexafluoro-2-butynechromium, 3629 Bis(cyclopentadienyl)lead, 3288 Bis(cyclopentadienyl)magnesium, 3271 Bis(cyclopentadienyl)manganese, 3272 Bis(cyclopentadienyl)niobium tetrahydroborate, 3318 Bis(cyclopentadienyl)pentafluorophenylzirconium hydroxide, 3696 Bis(cyclopentadienyl)phenylvanadium, 3698 Bis(cyclopentadienyl)titanium selenate, 3287 Bis(cyclopentadienyl)tungsten diazide oxide, 3279 Bis(cyclopentadienyl)vanadium diazide, 3280 Bis(cyclopentadienyl)zirconium, 3290 Bis(l,2-diaminoethane)diaquacobalt(III) perchlorate, 1787 Bis(l,2-diaminoethane)dichlorocobalt(III) chlorate, 1780 Bis(l,2-diaminoethane)dichlorocobalt(III) perchlorate, 1781 c/i-Bisf 1,2-diaminoethane)dinitrocobalt(III) iodate, 1782 Bis(l,2-diaminoethane)dinitrocobalt(III) perchlorate, 1778 Bis(l,2-diaminoethane)hydroxooxorhenium(V) perchlorate, 1785 Bis(l, 2-diaminopropane)-ds-dichlorochromium(III) perchlorate, 2609 1,10-Bis(diazonio)decaboran(8)ate, 0197... 

Caution. The decaborane is purified by sublimation at 60° at 10 mm. The sublimation apparatus should he situated in a hood which is well shielded. If air should accidentally contact decaborane at elevated temperatures, a violent oxidative decomposition might result. Decaborane is toxic therefore one shoidd avoid breathing the vapor or allowing the compound to contact the skin. 

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