26120-85-4Relevant articles and documents
UPDATING OF PENTACHLOROBENZENESULFONIC ACID
Armet, O.,Veciana, J.,Castaner, J.,Riera, J.,Carilla, J.,Riaza, J.
, p. 273 - 280 (2007/10/02)
The sulfonations of pentachlorobenzene (1) with 25percent oleum at 40 deg C or 140 deg C, or with 65percent oleum at 40 deg C give always excellent yields of pentachlorobenzenesulfonic anhydride (2).However, pentachlorobenzenesulfonic acid (3) is obtained when the working up of the reaction mixture is not mild enough to avoid the hydrolysis of the anhydride 2.Acid 3 is also synthesized starting from pentachlorophenol (4) via O-pentachlorophenyl dimethylthiocarbamate (6), its isomerization to S-pentachlorophenyl dimethylthiocarbamate (7) and final oxidation to 3.Pentachlorobenzenesulfonyl chloride (8) and anhydride (2) are also obtained from acid 3.Anhydride 2 reacts at 200 deg C with phenol 4 or pentachloroaniline (10) giving pentachlorophenyl pentachlorobenzenesulfonate (9), or a mixture of pentachlorobenzenesulfonyl pentachloroanilide (11) and pentachloroanilinium pentachlorobenzenesulfonate (12), respectively.Sulfonamide 11 can be obtained in two polymorphic forms and an ethyl ether solvate, for which interesting spectral and thermal differences are observed.
