Containers boron trichloride

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. 

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 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). 

A 5-1. three-necked flask is fitted with a stirrer (which may be of the glass-sleeve type lubricated with paraffin oil, or a mercury-sealed Hirshberg stirrer), an efficient condenser fitted with a calcium chloride drying tube, and a gas inlet tube. The gas inlet tube is connected with polyethylene tubing through a small bubble counter containing a nonvolatile hydrocarbon to the cylinder of boron trichloride. 

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 ... 

The boron trichloride can be reused in the experiment with only brief pumping at its melting point to remove excessive amounts of HC1. Traces of B2CU left in the BC13 have no adverse effects in subsequent runs. The reactor should be filled with nitrogen after all volatiles have been pumped out, opened to the air, and quickly put into a fume hood. The residues containing Cu, CuCl, and traces of boron chlorides, may fume slightly in air but they are not pyrophoric. 

Boron trichloride boils at 13°. To prepare the solution, the submitters poured liquid boron trichloride into a tared beaker containing dry xylene until the weight increased by 250 g. The beaker was in a methanol-ice bath. 

The checkers placed 250 ml. of dry xylene in a 500-ml. round-bottomed flask marked with a line corresponding to a volume of 424 ml. and with a gas inlet above the line. A cold finger containing a mixture of dry ice and methanol was attached to the flask, which was immersed in the same mixture. Gaseous boron trichloride (Matheson Co.) was passed in until the flask was filled to the 424-ml. line, and the cold solution was transferred to the dropping funnel. 

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... 

The reaction of ( + )-bulbocapnine methyl ether (42) with excess boron trichloride in methylene chloride containing 0.3% ethanol produces the catechol (43) together with the monophenol (44). However, with boron tribromide, it is the diphenol (45) which is produced. Both compounds (44) and (45) can be O-methylated with diazomethane to the dimethyl ether (46), and hydrolysis of (46) with dilute hydrochloric acid leads to (+)-corytuberine (47).43 Alternatively, methylation of (43), using diazomethane, affords (+)-corydine methyl ether (48). 

Boron trichloride has been reported to react with pseudohalide ions to give the mixed halogen-pseudohalogen ions BCl Z4 n (Z = CN-, NCO NCS, N3 ), none of which were isolated (107). However, only for the BC1 (CN)4 series were any individual mixed-ion llB resonances reported. The BX3OMe" ions [X = F (117), Cl (54), Br (54)) apparently disproportionate rapidly to give the BX4 ions. Early reports of fluorine-containing BF X4 species (X = halide, hydroxyl, etc.) have been summarized (162). 

Theoretically, any species that contains an unshared electron pair could act as a base. In fact, most ions and molecules that contain unshared electron pairs undergo some reactions by sharing their electron pairs. Conversely, many Lewis acids contain only six electrons in the highest occupied energy level of the central element. They react by accepting a share in an additional pair of electrons. These species are said to have an open sextet. Many compounds of the Group IIIA elements are Lewis acids, as illustrated by the reaction of boron trichloride with ammonia, presented earlier. 

Due to their reactivity towards substitution under conditions in which phenol itself is unreactive, 1-hydroxy-3-aikoxybenzenes require milder catalysts than generally employed for the former. Resorcinol monomethyl ether in benzene containing benzoyl chloride upon addition to boron trichloride (1 mole) in benzene at -lO C followed by refluxing for 10 hours and aqueous work-up at ambient temperature, afforded 2-hydroxy-4-methoxybenzophenone in 85% yield (ref.132). 

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