1343-93-7

Phosphotungstic acid is a white, crystalline solid classified as a phosphotungstate compound. Its reaction mechanism involves the formation of an acid complex through protonation by water. This can be represented by the equation: PW6O14(OH)2 + H2O → PW6O14(OH)3H+ + OH-. The resulting solution is highly acidic, typically having a pH of 2 or lower. 

Phosphotungstic acid (H3PW12O40) was used as an efficient and recyclable catalyst for the synthesis of polysubstituted quinolines through the Friedl?nder condensation of 2-aminoarylketone with carbonyl compounds, which was achieved by conventional heating under solvent-free conditions.^[1]

[1] Minoo Dabiri,  Sahareh Bashiribod. “Phosphotungstic acid: an efficient, cost-effective and recyclable catalyst for the synthesis of polysubstituted quinolines.” Molecules 14 3 (2009): 1126–44.