Pyridine,2,3,6-trichloro- (6515-09-9)

A process for the selective chlorination of a polychlorinated pyridine chosen from the group consisting of 2,6-dichloropyridine and 2,3,6-Trichloropyridine (CAS NO.6515-09-9)comprising continuously reacting chlorine in the gas phase with at least one of saidhalopyridines at a temperature of at least about 200° C. and in the presence of a catalyst selected from the group consisting of silicates, silicate clays, mineral earths and zeolites in combination with an additive selected from the groupconsisting of activated carbon, iron, zinc or a Lewis acid halide, whereby 2,6-dichloropyridine is selectively chlorinated to predominantly form 2,3,6-Trichloropyridine (CAS NO.6515-09-9), 2,3,5,6-tetrachloropyridine or mixtures thereof, and 2,3,6-Trichloropyridine (CAS NO.6515-09-9) isselectively chlorinated to predominantly form 2,3,5,6-tetrachloropyridine.