反应详情

温度

125 °C

Analogously to Example 3, a solution of carbodihydrazide in phenol is prepared from 3,200 g (64 mol) of hydrazine hydrate and 6,848 g (32 mol) of diphenyl carbonate and the water of hydration and also 1,500 ml of phenol are then distilled off. After addition of 3 g of dimethyltin oxide and 1,848 g (33.6 mol) of propionitrile, the mixture is heated to a weak reflux (125° C.). The temperature can be increased to 180° C. in the course of 11 hours under a continuous reflux. Thereafter, the evolution of NH3 has ended. Phenol is now distilled off at a bottom temperature of 160° C. under reduced pressure (decreasing to 15 mbar), the residue remaining liquid. Residual phenol is therefore removed under 1 mbar using an oil pump. After cooling, the residue is dissolved in 3 1 of hot water. 80 ml of diethylamine and 10 g of tartaric acid (to remove a slight turbidity caused by the catalyst) are added to the solution. A diethylamine excess and traces of phenol are removed by incipient distillation. After cooling to 10° C., the product is filtered off with suction, washed with 500 ml of cold 50% strength ethanol and dried at 100° C. in vacuo. 3,478 g (85% of theory) of 3-ethyl-4-amino-1,2,4-triazol-5-one of melting point 171° C. are obtained.

1. distillationthe water of hydration and also 1,500 ml of phenol are then distilled off
2. temperaturethe mixture is heated to
3. temperatureThe temperature can be increased to 180° C. in the course of 11 hours under a continuous reflux
4. distillationPhenol is now distilled off at a bottom temperature of 160° C. under reduced pressure (decreasing to 15 mbar)
5. customResidual phenol is therefore removed under 1 mbar
6. temperatureAfter cooling
7. dissolutionthe residue is dissolved in 3 1 of hot water
8. custom80 ml of diethylamine and 10 g of tartaric acid (to remove a slight turbidity
9. additionare added to the solution
10. customare removed by incipient distillation
11. temperatureAfter cooling to 10° C.
12. filtrationthe product is filtered off with suction
13. washwashed with 500 ml of cold 50% strength ethanol
14. customdried at 100° C. in vacuo