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|Section2= |Section4= |Section7= |Section8= }} Boron tribromide, BBr3, is a colorless, fuming liquid compound containing boron and bromine. It is decomposed by water and alcohols.〔(【引用サイトリンク】 url = http://www.cdc.gov/niosh/pel88/10294-33.html )〕 ==Chemical properties== Boron tribromide is commercially available and is a strong Lewis acid. It is an excellent demethylating or dealkylating agent for the cleavage of ethers, also with subsequent cyclization, often in the production of pharmaceuticals. The mechanism of dealkylation of tertiary alkyl ethers proceeds via the formation of a complex between the boron center and the ether oxygen followed by the elimination of an alkyl bromide to yield a dibromo(organo)borane. :ROR + BBr3 → RO+(−BBr3)R → ROBBr2 + RBr Aryl methyl ethers (as well as activated primary alkyl ethers), on the other hand are dealkylated through a bimolecular mechanism involving two BBr3-ether adducts. :RO+(−BBr3)CH3 + RO+(−BBr3)CH3→ RO(−BBr3) + CH3Br + RO+(BBr2)CH3 The dibromo(organo)borane can then undergo hydrolysis to give a hydroxyl group, boric acid, and hydrogen bromide as products. :ROBBr2 + 3H2O → ROH + B(OH)3 + 2HBr It also finds applications in olefin polymerization and in Friedel-Crafts chemistry as a Lewis acid catalyst. The electronics industry uses boron tribromide as a boron source in pre-deposition processes for doping in the manufacture of semiconductors. Boron tribromide also mediates the dealkylation of aryl alkyl ethers, for example demethylation of 3,4-dimethoxystyrene into 3,4-dihydroxystyrene. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「boron tribromide」の詳細全文を読む スポンサード リンク
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