Catechol-3,5-disulfonic acid

The formation of dimeric species is usually following the first step in the UO -chelate systems with catechol, catechol-3-sulfonic and catechol--3,5-disulfonic acids (Tiron) at pH 4 - 5 and probably accompanies other equilibria in the system of chromotropic acid at pH 3,9 - 4,2 ... 

Several metals, including iron, copper and tin, can fog emulsions. Emulsions can be partly stabilized by sequestering these metallic species with suitable ligands. Catechol derivatives are reported to be helpful in preventing fog from this source. Examples include 1,2-dihydroxy-benzene-4-sulfonic acid (sodium salt) and l,2-dihydroxybenzene-3,5-disulfonic acid (disodium salt).37... 

Most compounds of this type are cyclic sulfite and sulfate esters of aromatic 1,2-diols as well as anhydrides of aromatic 1,2-disulfonic acids. The simplest representatives with unsubstituted benzene rings are 1,3,2-benzodioxathiole 2-oxide (48) (catechol sulfite), the corresponding 2,2-dioxide (156) (catechol sulfate) and 2,1,3-benzoxadithiole 1,1,3,3-tetroxide (158) (1,2-benzenedisulfonic anhydride). Compound (48) was synthesized by refluxing catechol with thionyl chloride in the presence of pyridine. In a similar fashion, from 2-mercaptophenol 1,2,3-benzoxadithiole 2-oxide was prepared (81AG603). The dioxide (156) was obtained in two steps by reaction of catechol monosodium salt with sulfuryl chloride in benzene at 0-10 °C and subsequent reflux of the intermediate (155) in the presence of pyridine. 

Resorcinol (m-dihydroxybenzene) is of greater commercial importance than catechol. It was first produced by Wilhelm Komer in 1868 by alkali fusion of iodophenol. Current industrial processes for resorcinol production are based either on benzene-m-disulfonic acid, which is converted to the dihydroxy com-... 

The action of chlorosulfonic acid on di- and polyhydric phenols has been examined. Catechol (1,2-dihydroxybenzene, 151) reacts with the reagent (two equivalents) at room temperature (24 hours) to yield the 3,5-disulfonic acid 152. On the other hand, heating catechol 151 with excess reagent (10 equivalents) at 110°C afforded the corresponding disulfonyl chloride 153 (Equation 50). If the reaction mixture is heated at 150 °C (8 hours), the product was the cyclic sulfate of the 3,5-disulfonyl chloride 154 (Equation 50) which is probably formed by acid-catalysed dehydration of the initially formed hydrogen sulfate 155. ... 

The phenolic ring in estrone can be readily oxidized. Reaction of estrone with Fremy salts (peroxylamine disulfonate) affords a mixture of the two isomeric catechols. In a more controlled manner, treatment of estrone with 2-iodoxybenzoic acid (22-1) leads intially to a mixture of the 2,3-quinone (22-2) and its 3,4-isomer (22-3) (Scheme 3.22). These products are then reduced in situ with ascorbic acid to afford 2-hydroxyestrone (22-4) and 4-hydroxyestrone (22-5). 

---