ORGANOMERCURY COMPOUNDS. XXVI. THERMAL DECOMPOSITION OF MERCURIC 2,6-DISUBSTITUTED BENZOATES

Article abstract of DOI:10.1016/S0022-328X(00)80993-6

The main thermal decomposition path for mercuric 2,6-disubstituted benzoates, (RCO2)2Hg (R=2,6-X2C6H3; X=F, Cl, Br, or Me), can be varied considerably.In boiling dimethyl sulphoxide, decarboxylation occurs giving the corresponding diarylmercurial (X=F or Cl) or RHgO2CR derivative (X=Me or Br).There is considerable competition from reaction of the mercuric salt with the solvent in the last three cases.With boiling pyridine as medium, the 2,6-difluorobenzoate yields a mixture of R2Hg and RHgO2CR derivatives, but the 2,6-dichlorobenzoate only gives (RCO2)2Hg(py)2.Thermal decomposition of the mercuric benzoates under vacuum yields the carbozylic acids and complex mercuration products, mainly based on 3-mercurated 2,6-disubstituted benzoates, with partial additional mercuration and/or decarboxylation.Pyrolysis of mercuric 2,6-dichlorobenzoate at atmospheric pressure results in both mercuration and decarboxylation, giving m-dichlorobenzene as the main volatile product and a complex mercurial with 1,3-dimercurated-2,6-dichlorobenzene repeating units and 2,6-dichlorophenyl terminal groups.