| 摘要 |
<p>A process for the preparation of 2,3,5,6-tetrachloropyridine of formula (I) consists in that 3,3,5-trichloroglutarimide of formula (II) is reacted either a) with phosphorus trichloride or phosphorus oxytrichloride or mixtures thereof in the presence from the start of catalytic amounts of hydrogen chloride, followed by a conversion of polyphosphorus compounds formed into phosphorus oxytrichloride by supplying chlorine, optionally only after supplying further phosphorus trichloride, or b) with phosphorus trichloride and chlorine, optionally in the presence of phosphorus oxytrichloride as a solvent, followed by a dehydrochlorination of the reaction mixture and finally conversion of polyphosphorus compounds formed into phosphorus oxytrichloride by supplying chlorine, optionally only after supplying further phosphorus trichloride.</p> |
