Catechol → 4-Sulfopyrocatechol

Participants

Reaction Conditions

Reaction Steps

Catechol (180 g.) was added in portions to stirred sulfuric acid (138.5 ml.) so that the reaction temperature remained below 25° C. After addition was complete, the semi-solid mixture was heated at 45° C. for 60 minutes then cooled to room temperature and poured into ice-water (700 ml.). The solution was neutralized with solid barium carbonate, the barium sulfate collected, the filtrate acidified to pH 1 with concentrated sulfuric acid then refiltered. The filtrate was evaporated to leave crude 3,4-dihydroxybenzenesulfonic acid (182.40 g.) which was used without purification.

Provenance & Evidence