| Popis: |
The homogeneous sulfonation of 1,2-dihydroxybenzene (1), its monomethyl (2) and dimethyl ether (3) in concentrated aqueous sulfuric acid at 25°C has been studied and isomer distributions, as well as rate coefficients for the sulfonation of 1–3 and their monosulfonic acids, have been determined. In 73.5-87.5% H2SO4, 1 yields the 3- and 4-sulfonic acids in a ratio of 25:75, 2 yields the 4-, 5- and 6-sulfonic acids in a ratio of 46:36:18 in 73.5% H2SO4 and 50:39:11 in 87.5% H2SO4, whereas 3 yields only the 4-sulfonic acid. The remarkable absence of the 3-sulfonic acid ( 87.5% H2SO4, the 4-sulfonic acid of 1 and the 5-sulfonic acid of 2 are present in part in the form of their hydrogen sulfate. In that acid region, the 3- and 4-sulforic acids of 1 both yield the 3,5-disulfonic acid, the 4- and 6-sulfonic acids of 2 both yield the 4,6-disulfonic acid and the 4-sulfonic acid of 3 mainly yields the 4,6- together with some 4,5-disulfonic acid. |
