Ethane-1,2-disulfonic acid

In a similar manner to the preparation of 1,3,2-dioxathiolane 2-oxide from 1,2-dihydroxyethane and thionyl chloride, 1,2,3-oxadithiolane 2-oxide was prepared from 2-mercaptoethanol and thionyl choride <75ACS(A)414>. 1,2,5-Oxadithiolane 2,5-dioxide (66), the cyclic anhydride of ethane-1,2-disulfinic acid, was obtained by controlled hydrolysis of ethanebis(disulfinyl) chloride <76CRV747>. The corresponding 2,2,5,5-tetroxide (67) was obtained by treatment of ethane-1,2-disulfonic acid with thionyl chloride <(66HC(2l-i)l>. 

Being the cyclic anhydride of ethane-1,2-disulfinic acid, 1,2,5-oxadithiolane 2,5-dioxide (99) hydrolyzed to the parent acid in an almost quantitative fashion on boiling for 1 minute in water (76CRV747). In an analogous manner, 1,2,5-oxadithiolane 2,2,5,5-tetroxide (100) and its benzo-, naphtho- and thieno-fused derivatives were hydrolyzed by water or, more rapidly, by hot alkali to the corresponding 1,2-disulfonic acids or their salts, respectively (66HC(21-l)l). 

Mootz, D. and Wunderlich, H., Crystalline structure of acid hydrates and oxonium salts. IV Dioxonium-1,2-ethane disulfonate, Acta Crystallogr. B26,1820-1825 (1970). 

Arylalkanes and Arylalkenes (Table VIII, p. 181). Diphenylmethane is sulfonated exclusively in the para position rather than in the more hindered ortho position. The 4-sulfonic acid is prepared by treating diphenylmethane with chlorosulfonic acid in chloroform solution at 0 the 4,4 -disulfonic acid, by the action of oleum at 100 . 1,2-Diphenyl-ethane (bibenzyl) when heated with sulfuric acid " jdelds a mixture of a disulfonic acid (probably 4,4 ) and a tetrasulfonic acid. Oleum reacts with stilbene without affecting the olefinic linkage to 3deld a disulfonic acid of unknown structure. Triphenylmethane, sj/m-tetraphenyl-ethane, and tetraphenylethylene yield sulfonic acids containing one sulfo group for each benzene ring, probably in the para position. 

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