Boron trichloride, reaction

Boron trichloride, reaction with 2-aminobiphenyl, 46, 66 Boron trifluoride, in preparation of ni-tronium tetrafluoroborate, 47, 56 with hydrogen fluoride in isomerization of /-cymene to tM-cymene, 47, 41... 

As can be seen in Fig. 2.1, if the temperature is raised sufficiently, AG becomes negative and the diborane reaction proceeds at a much lower temperature than the boron trichloride reaction. 

Similar reactions occur with many other chlorine-containing compounds, BCI3 being produced (see Boron Trichloride reactions). Anhydrous borax and BCI3 are obtained when it is heated with sodium chloride at 800°C ... 

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). 

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). 

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] ... 

Another reagent system that has been recently employed in the Paal synthesis of thiophenes is the combination of bis(trialkyltin)- or bis(triaryltin) sulfides with boron trichloride. Known as the Steliou reagent,it has been utilized in the transformation of 1,4-diketone 11 to thiophene 12. Higher yields are obtained in shorter reaction times in contrast to the use of Lawesson s reagent. Additionally, others have noted the relative ease of the work-up procedure using the Steliou conditions, and the fact that the tributyltinchloride byproduct of the reaction is reusable. Similarly, the combination of the bis(trimethylsilyl)sulfide has been used in conjunction with trimethylsilyltriflate for the preparation of thiophenes in an analogous manner. ... 

Treatment of l,4 3,6-dianhydro-D-glucitol with boron trichloride gives l,6-dichloro-l,6-dideoxy-D-glucitol (20). Although methyl 6-chloro-6-deoxy-a-D-glucopyranoside (isolated as the tribenzoate) could be isolated from the reaction of methyl 3,6-anhydro-a-D-glucopyranoside with boron trichloride (21), the application to the isomeric furanoside derivative led to complex results. 

Sodium borohydride is a white crystalline solid produced from the reaction between sodium hydride and boron trichloride dissolved in a nonaqueous solvent ... 

A demonstration of the feasibility of a reaction is illustrated in the following example regarding the formation of titanium diboride using either diborane or boron trichloride as a boron source, as shown in the following reactions ... 

Coatings and monolithic components of h-BN are usually produced by CVD by the reaction of a boron halide with ammonia. MOCVD and plasma-CVD are also used. The reaction of boron trichloride and ammonia is as follows ... 

C21-0008. Sulfur tetrafluoride fluorinates boron trichloride according to the following unbalanced equation BCI3 + SF4 BF3 + SCI2 + CI2 This is both a redox reaction and a metathesis reaction, (a)... 

Dinitrogen tetroxide has a highly exothermic reaction with boron trichloride. 

With boron trichloride, phenyiamine forms a complex. The reaction is very exothermic if the medium is not cooled enough and if no solvent is used, nothing can be done to avoid detonation. 

Tris(alkylamino)boranes, B(NHR)3, can be synthesized through a simple reaction involving boron trichloride and an excess of the corresponding primary alky-lamine (scheme 17).57,58 This reaction may also lead to alkylaminoborazines of... 

On addition of boron trichloride, dropwise, to methanol an explosion and fire resulted. The academic reporter appears unaware that reaction of these was reported in 1834, and attributes the explosion to water in his methanol. Since the chloride is a gas, ability to add it dropwise is puzzling. Had a phonetic error meant PC13 was employed the fire would be intelligible, since phosphine would be formed as a pyrophoric byproduct. 

The procedure described here involves the use of copper, rather than mercury, as a chlorine-getter. In this case, presumably, the principal reaction is heterogeneous in nature and involves the attack of metallic copper by gaseous boron trichloride, according to the equation ... 

Tris(dimethylamino)borane has been prepared by dimethyl-aminolysis of boron trichloride, with or without solvent,1-5 and by the reaction of boron trifluoride with dimethylamine in the presence of a suitable Grignard reagent.6 The procedure described here is a modification of the reaction of dimethylamine with boron trichloride in pentane as the solvent. 

A 2-1. three-necked flask is equipped with a stirrer, a 500-ml. dropping funnel protected by a calcium chloride drying tube, and a reflux condenser topped with a potassium hydroxide drying tube. The reaction vessel is cooled in an ice-salt bath and is charged with 500 ml. of dry pentane and 293 g. (6.5 mols) of anhydrous dimethylamine. A solution of 117.2 g. (1 mol) of boron trichloride in 400 ml. of pentane, prepared by passing the gaseous chloride into chilled pentane, is added slowly with... 

The original method1 reported for the preparation of trichloroborazine involves the use of borazine. However, this procedure is not recommended because of the difficulty of preparing this heterocycle and its hydrolytic instability. More recently, this trichloroborazine has been prepared directly from ammonium chloride and boron trichloride at elevated temperatures with or without a solvent.2-8 Ammonium chloride may be replaced by a primary aliphatic or aromatic amine or its hydrochloride, and organodihaloboranes can be used in place of the boron trichloride to give the respective N- and B-substituted borazines.6 Boron tribromide has been used in analogous reactions to yield -B,/ , .B"-tribromoborazines.6... 

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