T-Butyl Hypobromite

Abstract

[1611-82-1] C4H9BrO (MW 153.02) (alkoxybromination of alkenes;2 bromination of alkanes;3 allylic bromination4) Physical Data: bp 44–45 °C/85 mmHg; mp −27 to −28 °C; d 1.33 g cm−3. Solubility: sol ether, CCl4, CH2Cl2. Analysis of Reagent Purity: the reagent can be assayed by thiosulfate titration of iodine liberated by the addition of the reagent to a solution of KI in aq HCl.5 Preparative Methods: prepared in 43% yield on a 0.18 mol scale by addition of t-butyl alcohol to a solution of Ag2SO4 and bromine in water.3 The product is isolated by distillation. Since much material is lost during the distillation, many workers have found it more convenient to prepare and use the reagent in solution. In one procedure the reagent is generated in CH2Cl2 solution from Hg2O, bromine, and t-butyl alcohol.6 It has also been prepared from NaBr, NaOCl, t-butyl alcohol, and acetic acid.2 Handling, Storage, and Precautions: reported3 to be stable for weeks at 0 °C in the dark. It decomposes at 85 °C, upon irradiation or by washing with 5% aq NaHCO3 solution. It also decomposes upon repeated washing with water. Should be handled in a fume hood.