The Dow Chemical Company

Richard E Crooks

Bart J Bremmer

G Edwin Vrieland

Gail E Vrieland

Symmetrical tetrachloropyridine (2,3,5,6-tetrachloropyridine) is prepared by reacting pentachloropyridine with a source of iodide ions in the presence of a proton source and a solvent medium. The reaction is preferably carried out in a polar, aprotic solvent medium and heated at a temperature of from about 100.degree. C. to about 200.degree. C.

Preparation of symmetrical tetrachloropyridine

A process for producing 4-bromotetrachloropyridine or symmetrical tetrachloropyridine in high purity comprises the selective transhalogenation of pentachloropyridine by a bromide salt in a polar aprotic solvent at a temperature from about 100.degree. C. to about 140.degree. C. followed optionally by selective debromination by hydrogen in the presence of a noble metal catalyst and an acid acceptor to form tetrachloropyridine.

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Bay City, MI, United States of America

Richard E Crooks