Trichloride, boron

Boron trichloride is a colorless, acid gas that fumes in the presence of moist air. It is packaged in steel cylinders as a liquid under its own vapor pressure of 19.1 psia (131.7 kPa abs) at 70°F (21.1°C). It reacts with water or moist air to produce hydrochloric and boric acid. 

Boron trichloride is available for commercial and industrial purposes in C.P. grade with a minimum purity of 99.9 percent by weight. A typical commercial (C.P.) grade analysis by weight is  

Boron trichloride Free chlorine as Ch Silicon as Si Phosgene 

It is also available to the electronic industry in Electronic and VLSI Echant grade. The impurity specification for the latter is  

The electronic industry benefits from boron trichloride in many applications. It is used in the production of optical fibers, as a 

TC Shipping Name Boron Trichloride TC Classification 2.3, 8 TC Label POISON GAS, CORROSIVE UN Number UN 1741 

Compressed Gas Association, Handbook of Compressed Gases Springer Science+Business Media New York 1999 

Colorless fuming liquid or gas with a pungent odor bp, 12.5°C.1 

Reacts rapidly with water, forming boric and hydrochloric acids.2 Decomposed by alcohol.1 

The gas irritates the eyes, skin, and respiratory system. The liquid irritates or burns the skin and burns the eyes. Swallowing would result in severe internal burning. Avoid breathing gas. Prevent contact with skin and eyes.2 

In warm weather, it will exist as a gas, in which case instruct others to keep out of affected area. Wear nitrile rubber gloves, laboratory coat, eye protection, and, if necessary, a self-contained breathing apparatus. Cover the spill with a 1 1 1 mixture by weight of sodium carbonate or calcium carbonate, clay cat litter (bentonite), and sand. When the boron trichloride has been absorbed, scoop the mixture into a plastic pail and, in the fume hood, very slowly add the mixture to a pail of cold water. Allow to stand for 24 hours. Test the pH of the solution and neutralize if necessary with sodium carbonate. Decant the solution to the drain. Treat the solid residue as normal refuse.2-5 

Package Lots. Place in a separate labeled container for recycling or disposal. Do not place in landfill.5 

Solubility sol saturated and halogenated hydrocarbon and aromatic solvents solubility in diethyl ether is approximately 1.5 M at 0 °C stable for several weeks in ethyl ether at 0 °C, but dec by water or alcohols. 

Form Supplied in colorless gas or fuming liquid in an ampoule BCl3-SMe2 complex (solid) and 1 M solutions in dichloromethane, hexane, heptane, and p-xylene are available. 

Handling, Storage, and Precautions a poison by inhalation and an irritant to skin, eyes, and mucous membranes. Reacts exothermically with water and moist air, forming toxic and corrosive fumes. Violent reaction occurs with aniline or phosphine. All operations should be carried out in a well-ventilated fume hood without exposure to the atmosphere. The gas can be collected and measured as a liquid by condensing in a cooled centrifuge tube and then transferred to the reaction system by distillation with a slow stream of nitrogen. 

One of the difficulties with the use of BCI3 arises from its tendency to fume profusely in air. The complex of BCI3 with dimethyl sulfide is solid, stable in air, and handled easily. By using a two-to fourfold excess of the reagent in dichloroethane at 83 C, aromatic methoxy and methylenedioxy groups can be cleaved in good yields.  

Tertiary phosphines are cleaved at the P-C bond to give diphenylphosphine oxides. Workup with Hydrogen Peroxide provides diphenylphosphinic acids (eq 1).  

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Boron trichloride, BCI3. Colourless mobile liquid, m.p. — 107°C, b.p. 12-5°C. Obtained directly from the elements or by heating B2O3 with pels in a sealed tube. The product may be purified by distillation in vacuo. It is extremely readily hydrolysed by water to boric acid. TetrachJoroborates containing the BCJ4 " ion are prepared by addition of BCI3 to metal chlorides. 

Boron tri-iodide, Blj (BClj plus HI at red heat or I2 plus NaBH ), m.p. 43°C, b.p. 2iO°C. It has very similar properties to boron trichloride. 

Other compounds containing lone pairs of electrons readily form co-ordinate links and in each case a change in spatial configuration accompanies the bond formation. The oxygen atom in dimethyl ether, CHj—O—CHj, has two lone pairs of electrons and is able to donate one pair to, for example, boron trichloride ... 

This compound, which contains atoms arranged tetrahedrally around the boron atom, can readily be isolated from a mixture of dimethyl ether and boron trichloride. On occasions a chlorine atom, in spite of its high election affinity, will donate an electron pair, an example being found in the dimerisation of gaseous monomeric aluminium chloride to give the more stable Al2Clg in which each aluminium has a tetrahedral configuration ... 

Boron forms a whole series of hydrides. The simplest of these is diborane, BjH. It may be prepared by the reduction of boron trichloride in ether by lithium aluminium hydride. This is a general method for the preparation of non-metallic hydrides. 

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 ... 

It forms an ion BCI4 only under special circumstances, and never in aqueous solutions (cf. BF3). Like the trifluoride, it is an electron pair acceptor, but the adducts formed tend to decompose more readily. Unlike the corresponding aluminium chloride, boron trichloride exists only as the monomer. 

Boron nitride can be prepared by allowing ammonia to react with boron trichloride. The first product is boron amide which decomposes on heating to give the nitride ... 

Boron exists naturally as 19.78% lOB isotope and 80.22% IIB isotope. High-purity crystalline boron may be prepared by the vapor phase reduction of boron trichloride or tribromide with hydrogen on electrically heated filaments. The impure or amorphous, boron, a brownish-black powder, can be obtained by heating the trioxide with magnesium powder. 

Boron trichloride, usually in conjunction with an additional Lewis acid, effects o-chloroacetylation of anilines. The resulting products are converted to indoles by reduction with NaBH4.[l], The strength of the Lewis acid required depends upon the substitution pattern on the ring. With ER substituents no additional... 

A solution of 2,3-dibromo-5-methoxyaniline (32 g, 0.17 mol) in CHjClj (300 ml) was stirred and cooled in an icc bath. Boron trichloride (1 M in CH2CI2, 180 ml, 0.18 mol), chloroacetonitrile (14.3 g, 0.19 mol) and TiC (1 M in CH CIj, 190ml, 0.19 mol) were added. The resulting mixture was refluxed for 1.5 h. The solution was cooled to room temperature and poured carefully on to a mixture of icc and 20% aq. HCl (700 ml). The organic layer was separated and the CH Clj removed by distillation. The residue was heated to 90°C on a water bath for 30 min. The solution was cooled and the solid collected by filtration. It was partitioned between ether (1.41) and 1 N NaOH (500 ml). The ether layer was washed with brine, dried over Na2S04 and evaporated. The residue was recrystallized from ethanol to give 2-amino-3,4-dibromo-6-methoxy-a-chloroacetophenone (55 g) in 90% yield. 

Phosphine Air, boron trichloride, bromine, chlorine, nitric acid, nitrogen oxides, nitrous acid, oxygen, silver nitrate... 

One of the first applications of this technique was to the enrichment of and "B isotopes, present as 18.7 and 81.3 per cent, respectively, in natural abundance. Boron trichloride, BCI3, dissociates when irradiated with a pulsed CO2 laser in the 3g vibrational band at 958 cm (vj is an e vibration of the planar, D j, molecule). One of the products of dissociation was detected by reaction with O2 to form BO which then produced chemiluminescence (emission of radiation as a result of energy gained by chemical reaction) in the visible region due to A U — fluorescence. Irradiation in the 3g band of BCls or "BCI3 resulted in °BO or BO chemiluminescence. The fluorescence of °BO is easily resolved from that of "BO. 

Hafnium Boride. Hafnium diboride [12007-23-7] HfB2, is a gray crystalline soHd. It is usually prepared by the reaction of hafnium oxide with carbon and either boron oxide or boron carbide, but it can also be prepared from mixtures of hafnium tetrachloride, boron trichloride, and hydrogen above 2000°C, or by direct synthesis from the elements. Hafnium diboride is attacked by hydrofluoric acid but is resistant to nearly all other reagents at room temperature. Hafnium dodecaboride [32342-52-2] has been prepared by direct synthesis from the elements (56). 

Although dichloroborane reacts direcdy with alkenes in the gas phase (118), its complexes with diethyl ether and dimethyl sulfide are so strong that direct hydroboration does not proceed (119,120). The addition of a decomplexing agent, eg, boron trichloride, is necessary for hydroboration. 

The reaction of 2-methyla2iridine with boron trichloride [10294-34-5] lea.ds to replacement of all three chlorides by ayiridine rings to form tri(methylethyleneimine) boron [17862-61-2] (152). The reaction of boron trifluoride [7637-07-2] with ethyleneimine at — 78°C proceeds via substitution and subsequent ring opening to yield A/-P-fluoroethyl-fl-difluorobora2ene (153). 

Phosgene can be employed in a variety of metal-recovery operations, eg, in the recovery of platinum, uranium, plutonium, and niobium (69—73). Phosgene has been proposed for the manufacture of aluminum chloride, beryllium chloride, and boron trichloride (74—76). Phosgene has been patented as a stabilizer, either by itself or in combination with thionyl chloride, for Hquid SO2 (77). 

Ti02/Na2C02/Na2AlF2/NaCl/Na2B40, at 1050°C (20). Very fine titanium diboride may be made by a gas-phase plasma process in which titanium tetrachloride and boron trichloride are reacted in a hydrogen gas heated by a d-c plasma (21). 

Boron filaments are formed by the chemical vapor deposition of boron trichloride on tungsten wire. High performance reinforcing boron fibers are available from 10—20 mm in diameter. These are used mainly in epoxy resins and aluminum and titanium. Commercial uses include golf club shafts, tennis and squash racquets, and fishing rods. The primary use is in the aerospace industry. 

In 1846 the first boric acid esters were prepared by reacting aUphatic alcohols and boron trichloride (1). The chemistry and properties of boric acid esters from that first paper through 1961 have been extensively reviewed (2). Short reviews were pubUshed in 1964, 1978, and two in 1980 (3,4). 

The reaction is irreversible and can be used to synthesize aUphatic and aromatic esters. In addition, there are no complications involving water removal or azeotrope formation. Boron tribromide can be used ia place of boron trichloride, but the bromide has a stronger tendency to halogenate the alkyl group of the alcohol (26). Boron tritiuoride does not give the ester, but gives either a complex or dehydrated product. 

Preparation. Hexagonal boron nitride can be prepared by heating boric oxide with ammonia, or by heating boric oxide, boric acid, or its salts with ammonium chloride, alkaU cyanides, or calcium cyanamide at atmospheric pressure. Elemental nitrogen does not react with boric oxide even in the presence of carbon, though it does react with elemental boron at high temperatures. Boron nitride obtained from the reaction of boron trichloride or boron trifluoride with ammonia is easily purified. 

Boron Trichloride. Boron trichloride is prepared on a large scale by the reaction of CI2 and a heated mixture of borax [1303-96-4] ... 

Boron trichlorides are highly reactive, toxic, and corrosive these ttihaUdes (BCl, BBr, BI ) react vigorously, even explosively, with water. High temperature decomposition of BX can yield toxic halogen-containing fumes. Safe handling, especially of BCl, has been reviewed (11,80). 

Boron Trichloride. Approximately 75—95% of the BCl consumed iu the United States is used to prepare boron filaments by CVD (7). These high performance fibers are used to reinforce composite materials (qv) made from epoxy resius and metals (Al, Ti). The principal markets for such composites are aerospace industries and sports equipment manufacturers. 

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