Hydrochloric Acid → Phenyl chloroformate

Participants

Reaction Conditions

Reaction Steps

A four-necked flask equipped with a gas inlet, a dry ice condenser, a mechanical stirrer, a thermocouple and a sampling port is charged with phenol (Aldrich, 287.5 g, 2.907 mol) and triphenyl phosphite (10.12 g, 32.61 mmol). The temperature is raised to 140° C. and phosgene (274 g, 2.77 mol) is added over a 465 minute period. Phosgene/phenol molar ratio is 0.95. A recirculating aqueous sodium hydroxide scrubber is used to neutralize the coproduct hydrochloric acid and to destroy traces of phosgene which are not condensed in the condenser. After the phosgene addition is stopped, a nitrogen stream is used to purge residual phosgene and the reactor is cooled to ambient temperature. The colorless crude product is isolated by vacuum distillation to give phenyl chloroformate (417.84 g, bp 73°-77° C. at 14 mm Hg) containing 6.6 percent by weight residual phenol. Selectivity to phenyl chloroformate is 95 mole percent based on phenol, 90 mole percent based on phosgene.

Provenance & Evidence