CORRESPONDENCE - Synthesis of DDT with Chlorosulfonic Acid as the Condensation Agent

Abstract

The 30 square foot filter has five auxiliary centrifugal pumps, one vacuum pump, one compressor for refrigeration, one blower, one agitator, and a motor drive; hence no decrease in the speci-

A study of the reported condensation of chloral with p-chlorobenzenesulfonic acid. An improved synthesis of p-chlorobenzenesulfonic acid*

“…chilled saturated NaCl solution to the filtrate from the original water-insoluble crude filter cake vielded 41. 5 Gm. dry sodium pchlorobenzenesulfonate (theoretical weight equivalent to 0.2 mol.…”

“…STUDY of the literature on the synthesis of A DDT indicated that while many condensing agents have been considered, only sulfuric acid (11), chlorosulfonic acid (4, 13), and hydrofluoric acid (15) have been successfully employed in its preparation. The technical production of DDT has been limited to the exclusive use of the h-st-mentioned condensing agent, even though it was pointed out recently that the economic operating limit of this method as expressed in terms of the percentage theoretical yield of pure DDT, is appreciably lower than that by the chlorosulfonic acid method (5). In 1945 an article by Giral and Range1 (7), in an obscure periodical, announced the synthesis of DDT in quantitative yield from chloral and p-chlorobenzenesulfonic acid according to the following reaction : CC13CH( 0 ) +Z~-CIC~H&O~H+H&O, Moreover, these authors postulated that the condensation of chloral with chlorobenzene in the presence of sulfuric acid occurs through the formation of an intermediate compound, p-chlorobenzenesulfonic acid and therefore they believed the quality of the DDT technical product might be improved through the direct synthesis of the insecticide according to the above-indicated equation.…”