A mixture of
400 ml. of diethylene glycol (Note
1) and
49.5 g. (0.14 mole) of 1,1-di-(p-chlorophenyl)-2,2,2-trichloroethane (Note
2) is placed in a
1-l. three-necked flask fitted with a
stirrer, a
reflux condenser, and a
thermometer. To this is added a solution of
63 g. (1.12 mole) of potassium hydroxide in 35 ml. of water. The mixture is stirred and refluxed for 6 hours at such a rate that the temperature is maintained at 134–137° (Note
3) and (Note
4). The mixture is allowed to cool and, with vigorous stirring, is poured into 1 l. of cold water. The insoluble material is filtered and washed twice with 50-ml. portions of warm water (Note
5). The filtrate is then boiled gently for 5 minutes with
2 g. of Norit; the
carbon is removed, the filtrate is acidified to litmus with
20% sulfuric acid (approximately 120 ml.), and then an additional 30 ml. of acid is added. The mixture is cooled to 0–5°; the precipitate is collected by filtration under suction, washed free of sulfate ions with water, and dried at 100–110°. The product is
di-(p-chlorophenyl) acetic acid melting at
163–165°; it weighs
27–28.5 g. (
69–73%). For purification, this material is dissolved in
100 ml. of boiling 95% ethanol, the solution is filtered, and approximately 45 ml. of water is added to the boiling filtrate until it just becomes turbid. The solution is then cooled to 0–5°, and the solid is removed by suction filtration. The material weighs
25–26 g. and melts at
164–166°.