ISO Factory Supply High Quality Phosphotungstic Acid

Phosphotungstic acid (PTA), tungstophosphoric acid (TPA), is a heteropoly acid with the chemical formula H3PW12O40. It is normally present as a hydrate. EPTA is the name of ethanolic phosphotungstic acid, its alcohol solution used in biology. It has the appearance of small, colorless-grayish or slightly yellow-green crystals, with melting point 89 °C (24 H2O hydrate). It is odorless and soluble in water (200 g/100 ml). It is not especially toxic, but is a mild acidic irritant. The compound is known by a variety of different names and acronyms.

After being acidified with phosphoric acid and hydrochloric acid in sodium tungstate solution, extracted with ethyl ether. Using Rosenheim and Jaenicke method, phosphotungstic acid is easy to prepare. 1000g sodium tungstate (Na2WO4 = 2H2O) and 160g sodium hydrogen phosphate two (Na2HPO4 = 2H2O) were dissolved in 1500mL boiling water. The 800mL concentrated hydrochloric acid is added to the mixture under constant stirring.

When half of the acid is added, phosphotungstic acid is separated. Because the precipitated acid must be pure, it does not need to be filtered out. The solution after cooling, adding reducing agent containing ether, until the mixture is divided into three by swing after the liquid layer so far. It takes about 600mL of ether. If necessary, add some water to dissolve sodium chloride.

The bottom layer is liquid and phosphotungstic acid ether compounds, water washed several times, each time adding sufficient ether to form third liquid layer. Then, in the ether liquid layer, the air is washed out without dust, so as to evaporate and crystallize. After filtration, the crystals are placed in the air in an open air, but do not contact the dust until they no longer have the odor of ether, and the yield is about 80%