Abstract: Phenyl (bromodichloromethy1) mercury reacts with carboxylic acids in benzene at 80" to give high yields of phenylmercuric bromide and dichloromethyl esters, RCOOCClzH. With trichloroacetic acid phenyl-mercury cleavage becomes an important side reaction. Evidence is presented that it is the monomeric RCOOH (not the hydrogen-bonded dimer) which is the reactive species. A mechanism in which the carboxylic acid reacts with ...