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°.