Натрий триполифосфорнокислый

Химические свойства

white or colourless crystals, granules or powder

Использование

Sodium tripolyphosphate is a binder, stabilizer, and sequestrant that is mildly alkaline, with a pH of 10, and moderately soluble in water, with a solubility of 15g in 100ml of water at 25°C. It is used to improve the whipping properties of egg-containing angel food cake mix and meringues. It reduces gelling of juices and canned ham and tenderizes canned peas and lima beans. It is a moisture binder in cured pork and protects against discoloration and reduces shrinkage in sausage products. In algin desserts, it functions as a calcium sequestrant. Sodium tripolyphosphate is also termed pentasodium tripolyphosphate and sodium triphosphate.

Методы очистки

Purify it by repeated precipitation from aqueous solution by slow addition of MeOH and dried in air. Also a solution of anhydrous sodium tripolyphosphate (840g) in water (3.8L) is filtered, MeOH (1.4L) is added with vigorous stirring to precipitate Na5P3O10.6H2O. The precipitate is collected on a filter, air dried by suction, then left to dry in air overnight. It is crystallised twice more in this way, using a 13% aqueous solution (w/w), and leaching the crystals with 200mL portions of water [Watters et al. J Am Chem Soc 78 4855 1956]. Similarly, EtOH can be added to precipitate the salt from a filtered 12-15% aqueous solution, the final solution containing ca 25% EtOH (v/v). Air drying should be at a relative humidity of 40-60%. Heat and vacuum drying should be avoided. [Quimby J Phys Chem 58 603 1954, Klement in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I p 547 1963.]