Phosphotungstic acid is colorless, pale-white powder or light yellow fine crystal, it has acidity and oxidation-reduction quality which can be used as multifunctional new type catalyst of high catalytic property and stable. It can be used for homogeneous and heterogeneous reactions, and even can be used as a phase transfer catalyst, is friendly to environment which is green catalyst. It is slight weathering, soluble in alcohol, ether and water, and dissolved in about 0.5 parts water.
Mainly used as reagent for a variety of alkaloids, nitrogenous base, phenol, protein, peptone, amino acids, uric acid, urea, blood and carbohydrate reagent, and biological staining.
(1) Catalyst by organic synthesis reaction is used to take place of liquid acid which may cause environmental pollution, like sulfide acid, hydrofluoric acid, aluminium trioxide and so on. It is used as a newly developed catalyst abroad.
(2)Biochemical reagents and chromatography reagents：Commonly used as precipitation, oxidation and color developing agent in the seperation, identification of drug and toxicology research of chemical poison, medicolegal expertise and analysis of biomaterial. By analyzing the outcoming phosphotungstic acid to identify phosphorous insecticide in fruit, vegetables, plants and foods.
(3) Also used as biological reagent and pigment. It is used to precipitate proteins, alkaloids and certain amino acids. Compared to insolubility of potassium phosphotungstate and ammonium phosphotungstate, sodium phosphotungstate can be used as reagent due to its solubility.
Below are steps of using sodium tungstate as raw material to produce high purity phosphotungstic:
(1) Mix sodium tungstate solution with inorganic acid solution until active tungstic acid precipitation is obtained.
(2) Mix active tungstic acid precipitation with phosphoric acid solution until active tungstic acid precipitation get totally dissolved, then phosphotungstic solution is obtained;
(3) Adding inorganic acid precipitant into phosphotungstic acid solution to make it subside, after filtration and crystallization, high purity phosphotungstic acid can be obtained.