Chlorodifluoromethane → Phosphonic acid, (difluoromethyl)-, diethyl ester

Participants

Reaction Steps

A sample of 6.82 g (171 mmol) of 60% NaH in mineral oil was washed twice with 30 ml of petroleum ether and was suspended in 130 ml of THF under argon. A solution of 22 ml (171 mmol) of diethyl phosphite was added dropwise over 45 minutes and the exotherm was controlled with a water bath. After stirring for an additional hour, 42 g (490 mmol) of chlorodifluoromethane was bubbled through the solution over 4.5 hours, while the internal temperature was maintained between 25° and 35° C. with a cool water bath. The white suspension was allowed to stir overnight, was diluted with hexane and filtered through Celite. The filtrate was evaporated to provide 27.6 g of a crude, pale yellow liquid. The crude material was fractionally distilled at 10 mm to provide 5.21 g (16%) of impure title compound (b.p. 82°-84° C.), followed by 20.66 g (64%) of title compound (b.p. 84°-86° C.) as a colorless liquid which contains a trace of impurity.

Provenance & Evidence