Boron -bromide BBr

Boron Bromide. Approximately 30% of BBr produced in the United States is consumed in the manufacture of proprietory pharmaceuticals (qv) (7). BBr is used in the manufacture of isotopicaHy enriched crystalline boron, as a Etiedel-Crafts catalyst in various polymerization, alkylation, and acylation reactions, and in semiconductor doping and etching. Examples of use of BBr as a catalyst include copolymerization of butadiene with olefins (112) polymerization of ethylene and propylene (113), and A/-vinylcarbazole (114) in hydroboration reactions and in tritium labeling of steroids and aryl rings (5). 

BBrs Boron bromide, 3 27, 29 BCla Boron chloride, 3 27, 28, 29... 

BBr, [l0B]Boron bromide, 22 219 BClF4PtSjC6H,B, Platinum(Q), chloro-tris(dimethyl sulfide)-, tetrafluorobor-ate(l -), 22 126... 

Scheme 8.88. A representation of the acid-catalyzed fragmentation of methyl phenyl ether (anisole) by the reaction with both hydrogen iodide (HI) and boron tribromide (BBrs). In the first case, iodomethane (methyl iodide, CH3I) and phenol are formed. In the second case, bromomethane (methyl bromide, CHsBr) and phenol result. The formation of methyl phenyl ether (anisole) from the reaction between methyl iodide and sodinm phenoxide is also shown.

BCl, BBr, and BI undergo exchange reactions to yield mixed boron hahdes. Exchange reactions also occur with trialkyl, triaryl, trialkoxy, or triaryloxy boranes and with diborane. Anhydrous metal bromides and iodides can be prepared by the exchange reaction of the metal chloride or oxide and BBr or BI (21)-... 

Boron tribromide [10294-33A], BBr, is used in the manufacture of diborane and in the production of ultra high purity boron (see Boron, ELEMENTAL BoRON COMPOUNDS). Anhydrous aluminum bromide [7727-15-3], AIBr., is used as an acid catalyst in organic syntheses where it is more reactive and more soluble in organic solvents than AlCl. Tballium bromide [7789AOA], TlBr, is claimed as a component in radiographic image conversion panels (39). 

Preparation from boron trifluoride and aluminum bromide. Cleavage of an ether is effected by adding BBrj to the ice-cold ether (3 equiv.), refluxing the mixture, and removing the alkyl bromide the orthoboric ester is then hydrolyzed with 10% 3 n-Bu—O—Bu-n + BBr, —(n-BuO)jB+3n-BuBr... 

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