Manufacturing Process
2-Phenyl-2-hydroxy-butyl carbamate was prepared by the following method:
49.81 g of 2-phenyl-1,2-butanediol and 25.01 g of pyridine were dissolved in
500 ml of benzene and cooled to 5°C. 34.01 g of ethyl chloroformate was
added over a period of 36 hour at 4°C to 8°C. The reaction mixture was
warmed to room temperature and stirred for 2 hours and then extracted with
100 cc each of the following:
Water, 15% hydrochloric acid, 10% sodium bicarbonate and finally water. The
solvent was stripped off. The residual oil was mixed with 300 ml of 28%
aqueous ammonia for 1 hour. The ammonia and water were vacuum distilled
at a temperature of 40°C or less. Then 300 cc of carbon tetrachloride was
added and the solution dried with sodium sulfate. The solution was cooled at
0°C and then filtered. The crystals were washed with cold carbon tetrachloride
and vacuum dried. The yield was 57 g of dried product having a melting point
of 55°C to 56.5°C.
