4-бромфенола

Химические свойства

4-Bromophenol is a pinkish-brown crystalline solid. four-sided biconical crystal precipitated from ether or chloroform. The melting point is 66.4 ℃, and a small amount of water can reduce the melting point a lot. Soluble in water, chloroform, easily soluble in ethanol, ether and glacial acetic acid, soluble in 7 parts of water.

прикладной

4-Bromophenol is a phenolic derivative that It can used as a reagent in Stille reactions or Intermediates of Liquid Crystals.

Подготовка

4-Bromophenol is synthesized by bromination of phenol. The bromine and carbon disulfide solution was added to the phenolic carbon disulfide solution, and the addition was started below 5°C, and the addition was completed under stirring for 2 hours. Phenol and bromine are approximately equimolar ingredients. Distill the reactant to remove carbon disulfide, and then conduct fractional distillation under reduced pressure to collect fractions at 145-150°C (3.32-3.99kPa) to obtain the product. Yield 80-84%.

Синтез

m-Bromoaniline (50 g) is dissolved by boiling in a mixture of water (400 ml) and sulfuric acid (50 ml). The solution is then cooled to 10℃ and diazotized by the addition of sodium nitrite (21 g) dissolved in a small amount of water, The resulting diazonium salt solution is run in a thin stream during fifteen to thirty minutes into a boiling mixture of water (300 ml) and sulfuric acid (100 ml) contained in a flask fitted with a dropping funnel, a steam inlet tube reaching to the bottom of the flask, and an efficient condenser set for downward distillation. During the addition of the diazonium salt solution the acid solution is heated so that its volume remains constant, and steam is passed in at such a rate that at the end of the addition approximately 1 liter of distillate has been collected. Steam distillation is then continued until 2-liters of distillate has been collected. To this is added sodium chloride (150 g), and the phenol is extracted with ether, using portions of 200, 100, and 100 ml. The ether is removed from the combined extracts and the product is distilled under reduced pressure. Eight runs of 50 g, each of m-bromoaniline gave 330 g of crude m-bromophenol boiling at 100-140℃ (20-30 mm.). Redistillation gave 313 g (77.8%) of m-bromophenol which boiled at 125-130℃ at 25 mm. Treatment of this 313 g of product with sodium hydroxide and methyl sulfate gave 285 g of m-bromoanisole (4-bromophenol), b. p. 100℃ at 20 mm[1].

Методы очистки

Crystallise the phenol from CHCl3, CCl4, pet ether (b 40-60o), or water and dry it at 70o under vacuum for 2hours. [Beilstein 6 IV 1043.]