Barium 5-(tert-butyl)-2,3-dihydroxybenzenesulfonate

Catechols and their derivatives attract great scientific interest due to the broad spectrum of their functional properties, including complexation, redox behavior, association ability and antioxidant activity. Because of the low molecular mass and two-electron redox process, they are considered to be a promising energy storage compound in different types of electrochemical power sources, such as metal-ion batteries or redox flow batteries. Herein, we report a preparation of the sterically hindered sulfonated catechol, namely the barium salt of 5-(tert-butyl)-2,3-dihydroxybenzenesulfonic acid, by the direct sulfonation of 4-tert-butylcatechol, by concentrated sulfuric acid. The proposed procedure is green and atom-economic, providing the desired product in high yield after simple purification. The solvent-free procedure is inexpensive and highly scalable, which enables direct industrial production of the title product. The resulting product was characterized by the H-1 and C-13 nuclear magnetic resonance (NMR) and ESI-high resolution mass spectrometry (ESI-HRMS).