Properties of sodium tripolyphosphate?

Sodium tripolyphosphate (Sodium Tripolyphosphate, STPP), chemical molecular formula was Na5P3O10, molecular weight 368, commonly known as the five or three sodium, sodium phosphate, phosphoric acid five sodium or coke sodium metaphosphate. Sodium tripolyphosphate is a white granular powder, soluble in water, insoluble in ethanol, aqueous solution was alkaline, combined with various metal ions ability. There are usually anhydrous (Na5P3O10) and six water (Na5P3O10 · 6H2O) two, anhydrous and type I (high temperature type) and type II (low temperature). Sodium tripolyphosphate product industry is often white solid powder mixture of type I and type II (also contain a small amount of normal sodium phosphate, sodium pyrophosphate and sodium hexametaphosphate etc.), the proportion of content of type I and type II products, depends on the conditions of production process. Products are hygroscopic, soluble in water, aqueous solution is alkaline. No matter in the water, solution or in the air, its hydrate is six water. Sodium tripolyphosphate chelating, suspension, dispersion, emulsion, gel, pH buffer effect, can be used as the main additives, synthetic detergent industry water soft water, tannery pretanning agent, dyeing agent, catalyst in organic synthesis, pharmaceutical industry and food additives such as dispersing agent. At present, its largest application is still powder synthetic detergent auxiliaries.