1,3-ベンゼンジスルホン酸

Benzene-1,3-disulphonic acid is formed as the main product in the sulfonation of benzene or benzenesulfonic acid with excess oleum at temperatures of 80 – 250 ℃. In proportion to the oleum concentration and reaction temperature 1 – 29% of diphenyl sulfone disulfonic acid is formed as an undesired byproduct.

純化方法Free it from H2SO4 by conversion to the calcium or barium salts (using Ca(OH)2 or Ba(OH)2, and filtering). The calcium salt is then converted to the potassium salt, using K2CO3. Both the potassium and the barium salts are recrystallised from H2O, and the acid is regenerated by passing through the H+ form of a strong cation exchange resin. The acid is recrystallised twice from conductivity water and dried over CaCl2 at 25o. [Atkinson et al. J Am Chem Soc 83 1570 1961.] It has also been crystallised from Et2O and dried in a vacuum oven. The S-benzylisothiuronium salt has m 214.3o (from EtOH/H2O). [Beilstein 11 IV 553.] It is best kept as the disodium salt [831-59-4] which decomposes on heating [Beilstein 11 H 199, 11 I 48, 11 II 213, 11 III 453.]