Benzene Sulphochloride

On Sulphonyl Chlorides and Sulphonamides.—The conversion of benzenesulphonic acid into its chloride and amide shows that derivatives of sulphonic acids, analogous to those of carboxylic acids, can be obtained. The sulpho-chlorides are much less reactive than are the chlorides of the carboxylic acids benzene sulphochloride, for example, can be dis-stilled in steam almost without decomposition. 

The decomposition by alkalis of benzene sulphohydroxamic acid— from benzene sulphochloride and hydroxylamine—likewise leads, as was already mentioned, to the sulphinic acid (Piloty). 

Thiophenol.—Benzene sulphochloride (8 g.) is allowed to run in small portions from a dropping funnel into a round-bottomed flask containing 20 g. of finely granulated tin and 50 c.c. of concentrated hydrochloric acid. During the addition of the sulphochloride and until most of the tin has dissolved, the flask, which is fitted with a double neck attachment carrying a reflux condenser, is heated on the boiling water bath. The mercaptan produced is distilled with steam and extracted from the distillate with ether. The ethereal solution is dried over sodium sulphate, the ether is removed by distillation, and the thiophenol which forms the residue is likewise distilled. It passes over as an almost colourless liquid at 173°. 

Kolbe has now begun to use Odling s notation (see p. 462) of dashes to represent the atomicity of a radical. Gerhardt and Chancel had previously given a table of compounds in which replaced carbon monoxide C 0 , and announced the discovery of benzene sulphochloride, C6H5SO2CI, as chlorure phenylsulfureux , C H S 0 C1. 

Since N02 and S03H are substituents of the second order, a second substituent enters in the m-position. Oleum containing a high percentage of sulphur trioxide finally converts benzene into benzene tri-sulphonic acid. Chlorosulphonic acid condenses with aromatic hydrocarbons, giving aryl sulphochlorides. 

A sulphochloride of tungsten, SWSg.WCls, has been obtained by heating the hexachloride with liquid hydrogen sulphide in a sealed tube for thirty-six hours at 60° to 05° C. It is a brown powder, insoluble in carbon disulphide, alcohol, or benzene it is decomposed by water. If heated to redness in the air, it takes hre. It is readily oxidised by nitric acid or fused 230tash. 

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