Chloroform → 3-Chloro-2-hydroxybenzaldehyde

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A sodium hydroxide solution (266 g, 6.65 mol in 1000 ml water) in a 3000 ml round bottom flask, equipped with a mechanical stirrer, addition funnel (250 ml), and a reflux condenser was warmed to 60° C. o-Chlorophenol (126 g, 0.98 mol) was added, dissolving instantly. Chloroform (262 g, 2.20 mol) was then introduced slowly over a one-hour period. After stirring at 60° C. for an additional two hours, the temperature was raised to 80° C. for sixteen hours. The excess chloroform was then allowed to distill off, the reaction acidified with 6 N sulfuric acid, and the mixture steam distilled. Six liters of distillate were extracted with ether, the ethereal solution dried with MgSO4, the slurry filtered, and the solvent evaporated under reduced pressure. A yellow oil composed of both the desired product and 3-chloro-4-hydroxybenzaldehyde remained. Pouring the oil into 500 ml of vigorously stirred hexane generated a white precipitate of 3-chloro-4-hydroxybenzaldehyde which was filtered off. Yield: 8%. The hexane filtrate was evaporated under reduced pressure yielding an oil which crystallized upon standing at room temperature for 24 hours. The yield of 3-chloro-2-hydroxybenzaldehyde was 8.01 g (5%), m.p. 51°-53° C.

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