Preparation of Bis l-Hydroxy-2,2,2-Trichloroethyl Urea

To a flask equipped with a mechanical stirrer water, condenser, and thermometer was added 162.2 g (1.1 mole) of chloral, 100 ml water, and 150 ml of concentrated HCl. The mixture was stirred at 70-80°C while 30 g (0.5 mole) of urea was added all at once. The resulting mixture was stirred for 5 hr to yield a white precipitate. The precipitate was filtered, washed with water until the wash water was pH 7.0, and then dried. The product is recrystallized from aqueous ethanol to give 101.2 g white needles (57% yield), m.p. 193°-194°C. 

The use of solvents to prepare the above compound can be avoided as described in reference 35. However, special equipment is required in order to allow efficient stirring of the solid reaction mixture. The structure of an isomer of the above compound was said to be obtained on recrystallization from aqueous methanol, but it was not clearly defined. 

Propylene oxide was reported to be capable of reacting with the above compound to give polymers useful for flame-retarding polyurethane foam [36]. 

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