Hydrochloric Acid → Phenol

Beteiligte Stoffe

Reaktionsschritte

A 1 liter four-necked flask, provided with mechanical stirrer, dropping funnel, thermometer and reflux condenser was charged with a mixture of 30 grams of sodium methylate and 400 grams of diethylene glycol diethyl ether. During the course of 1 hour at 25° C 48 grams of 5-oxohexanoic acid methyl ester were uniformly added. When the ester addition was terminated, gas chromatographic analysis indicated that the ester had completely reacted. Next, the reaction mixture was acidified to pH 3.5 by adding 46 ml of concentrated hydrochloric acid and the formed crystalline sodium chloride was filtered off with suction. Gas chromatographic analysis of the filtrate indicated a yield of cyclohexanedione-1,3 of 35.0 grams ≈ 94 %. 75 g of the filtrate which, according to gas chromatographic analysis, contained 6 grams of cyclohexane-dione-1,3 were added, over a period of 1 hour, to a dehydrogenation mixture heated to 185° - 190° C and consisting of 50 ml diethylene glycol diethyl ether and 1 gram of catalyst (0.1 gram palladium on 0.9 gram of carbon). As soon as the development of gas was terminated (1210 ml), the reaction mixture was cooled while flushing with nitrogen, the catalyst was filtered off with suction, washed with a little diethylene glycol diethyl ether, the filtrate was analyzed by gas chromatography and then distilled under reduced pressure. After a solvent fraction (boiling point under 15 mm Hg 78- 84° C) and a small amount of phenol, pure resorcinol was obtained.

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