Add time:08/07/2019         Source:sciencedirect.com

The redox chemistry of Alizarin Red S (1,2-dihydroxy-9,10-anthraquinone-3-sulfonate) was studied as function of pH by photometry, potentiometric titration and cyclic voltammetry. Dependent upon solution pH three species of the oxidised form of Alizarin Red S are present. Electrochemical reduction of the anthraquinone group leads to 1,2,9,10-tetrahydroxy-anthracene-3-sulfonate. The four phenolic hydroxyl groups dissociate with increasing pH value, above pH 12 a tetra anion is the main species in solution. Cyclic voltammetry experiments in unbuffered solution indicate that the overall cathodic reduction contains electron transfer and pH-dependent protonation reactions. Above pH 12 dispersed Vat Yellow 1 could be reduced by indirect cathodic electron transfer using the fully deprotonated system as reversible redox couple. In cyclic voltammetry a reduction potential of (Ep)d = −900 mV (vs. Ag/AgCl/3 M KCl) was observed, which is sufficiently negative to reduce Vat Yellow 1. No indication for an indirect cathodic reduction of Vat Yellow 46 could be registered.

We also recommend Trading Suppliers and Manufacturers of Vat Yellow 46 (cas 12237-50-2). Pls Click Website Link as below: cas 12237-50-2 suppliers