Reaction of a mixture of 6-chlorocyclohexa-2,4-dienones (4) and (5) with chlorine in acetic acid gives the tetrachloro ketones (2) and (3), the major products of chlorination of 2,3,6-trimethylphenol (1a) or 4-chloro-2,3,6-trimethylphenol (1b). Reactions of this mixture of 6- chlorocyclohexa-2,4-dienones (4) and (5) in acetic acid with chlorine acetate, chlorine, chlorine in the presence of sodium acetate, and in benzene with nitrogen dioxide are described. -Ray crystal structure determinations are reported for compounds (3), (6)-(8) and (11)-(13).