Sodium Hydroxide → HCID 178524411, compound

Participants

Reaction Steps

To an agitated solution of 216.0 g (5.4 mole) of sodium hydroxide pellets in 2.25 liters of 5% (1.51 moles) sodium hypochlorite solution was added 150.0 g (1.08 mole) of 2-hydroxynicotinic acid. Temperature of the mixture was 20°-32° C. After 4 hr mass spectrographic analysis showed some starting 2-hydroxynicotinic acid was present. An additional liter of 5% (0.67 moles) of sodium hypochlorite solution was added and stirring was continued overnight. Starting 2-hydroxynicotinic acid was no longer present. Slow acidification with 690 ml of concentrated of the reaction mixture under agitation over a 1.25 hr period resulted in conversion to a mass of porous fluffy salt crystals. As more acid was added severe bubbling occurred and half of the reactor contents had to be removed. Both portions were completely acidified, the total of additional acid being 100 ml concentrated hydrochloric acid. The mixture was filtered on a large sintered glass funnel and crystals became gooey and difficult to handle. Once the filter cake had reached a mud-like stage, it was slurried in 500 ml of 6N hydrochloric acid and refiltered. The filter cake was rinsed with 350 ml of water and subjected to vacuum for several hours. The filter cake was rinsed first with 300 ml of 1:1 isopropyl ether/isopropyl alcohol then with 300 ml of 3:1 isopropyl ether/isopropyl alcohol and subjected to vacuum filtration for several hours. The crystals were desicated under vacuum using a heat lamp. The weight of dry crystals was 84.5 g (45.1%). However 1HNMR analysis indicated that the product contained 10-12% impurity≠(3,5-dichloro-2-hydroxypyridine). See Example 3 for the method of computing impurity. The original filtrate also contained this impurity.

Provenance & Evidence