Hydrochloric Acid → HCID 178517141, compound

Temperature

80 °C

Into a four-necked flask of 1 l capacity were charged 64.8 g (0.6 mol) of o-phenylenediamine, 31.3 g (0.5 mol) of hydrochloric acid, 36.0 g (0.6 mol) of urea and 50 ml of xylene, and a reaction was effected at 140°-150° C. for 5 hours while distilling out 20 ml of water. Then, the reaction product was charged into a four-necked flask of 1 l capacity, into which 30 g (0.75 mol) of sodium hydroxide and 600 ml of water had been previously charged, and the resulting mixture was stirred at 80° C. for 15 hours. Then, thus treated mixture was filtered while it was hot, and the filtrate was cooled to form a precipitate. The resulting precipitate was filtered, and the filter cake was washed with water to obtain the aimed 2-hydroxybenzimidazole having a melting point of 316°-317° C. in an yield of 53.6 g (66.6%).

1. distillationwhile distilling out 20 ml of water
2. additionhad been previously charged
3. filtrationThen, thus treated mixture was filtered while it
4. temperaturethe filtrate was cooled
5. customto form a precipitate
6. filtrationThe resulting precipitate was filtered
7. washthe filter cake was washed with water

ORD record

ord-c125961a713a4cc2a2e2dd9249960ed9

Source dataset

uspto-grants-1992_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05140055