METHOD FOR PREPARING TETRACHLOROPICOLINIC ACID Russian patent published in 2006 - IPC C07D213/79 C07D213/84 C07D213/61 

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for preparing tetrachloropicolinic acid. Method involves interaction of 2-cyanopyridine with chlorine in presence of catalysts wherein phosphorus chlorides are used in the amount 2-60 weight % of the initial load of 2-cyanopyridine, and phosphorus oxychlorides also. The chlorination process is carried out in the melt at temperature 120-200°C and under pressure up to 0.6 MPa followed by dosing the reaction mass into a mixture of water with sulfuric acid, and then hydrolysis is carried out in the presence of phosphoric acid formed after hydrolysis of phosphorus chlorides. The end product is isolated by the known procedures. Method provides simplifying the process by using the standard equipment, improving ecological indices and reducing energy consumptions.

EFFECT: improved preparing method.

2 cl, 6 ex