反应详情

According to a preferred embodiment of the process of the invention, 3,5-dichloro-2-pyridone is suspended in toluene, the water present is separated by azeotropic distillation, 0.05-0.15 mol of N,N-dimethylformamide per mol of 3,5-dichloro-2-pyridone is added, and 1.0-1.3 mols of phosgene per mol of 3,5-dichloro-2-pyridone are introduced at 75°-80° C. After the addition of phosgene has been completed, the reaction mixture is allowed to react for a further one hour at 75°-80° C., and the excess phosgene is subsequently reacted with aqueous ammonia. The phases are afterwards separated, the solvent is distilled off from the organic phase, and 2,3,5-trichloropyridine is obtained as a melt.

1. additionis added
2. customto react for a further one hour at 75°-80° C.
3. customThe phases are afterwards separated
4. distillationthe solvent is distilled off from the organic phase