PREPARATIONS 249 the unchanged dimethy!aniline can therefore be recovered by steam-distillation. The reaction product is then cooled and the insoluble sulphonyl-methylaniline filtered off. The filtrate is then acidified, and the sulphonyl-aniline thus precipi-tated. Hydrolysis of these two sulphonyl compounds then regenerates the secondary and primary amines respectively. Although benzenesulphonyl chloride has for simplicity been used in the above discussion, toIuene-/>-suIphonvl chloride, CH 3 C 6 H 4 SO 2 Cl, is more fre-quently used in the laboratory, owing to its much lower cost, the latter being due in turn to the fact that toluene-/>-sulphonyl chloride is a by-product in the commercial preparation of saccharin. Toluene-p-sulphonyl chloride is a crystalline substance, of m.p. 68°: the finely powdered chloride will, however, usually react readily with amines in the Schotten-Baumann reaction; it does not react so readily with alcohols, but the reaction may be promoted consider-ably by first dissolving the chloride in some inert water-soluble solvent such as
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This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.