Benzenetrisulfonic acid

Sulfonation. Benzene is converted iato benzenesulfonic acid [98-11-3] C H SO, upon reaction with fuming sulfuric acid (oleum) or chlorosulfonic acid. y -Benzenedisulfonic acid [98-48-6] CgHgS20, is prepared by reaction of benzene-sulfonic acid with oleum for 8 h at 85°C. Often under these conditions, appreciable quantities ofT -benzenedisulfonic acid [31375-02-7] are produced. 1,3,5-Benzenetrisulfonic acid [617-99-2] C H S Og, is produced by heating the disulfonic acid with oleum at 230°C (21). 

In spite of their similarity potassium hydroxide and sodium hydroxide differ in their effects. Potassium benzenesulfonate and potassium hydroxide give an almost quantitative yield of phenol, but only a partial yield is obtained in sodium hydroxide. This relationship is, however, reversed when one tries to convert benzenetrisulfonic acid into phloroglucinol with potassium hydroxide... 

When aminobenzenesulfonic acid is heated with sulfuric acid and phosphoms pentoxide, 2-amino-l,3,5-benzenetrisulfonic acid [64775-08-4] is the product (43). 

Phloroglucinol is formed by alkaline fusion of many vegetable products, for instance, maclurin 1 or kino.2 It is also formed to a small extent by the fusion of phenol with sodium hydroxide,3 and to a larger extent by fusing resorcinol with sodium hydroxide.4 It has been produced by fusing 1,3,5-benzenetrisulfonic add with sodium hydroxide 5 and 3,5-dibromophenol with potassium hydroxide. The best yields, however, are obtained by boiling a dilute solution of triaminobenzene hydrochloride 7 or triamino-benzoic acid hydrochloride 8 with water. 

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