Disodium phosphate (DSP), or disodium hydrogen phosphate, or sodium phosphate dibasic, is an

inorganic compound An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds⁠that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''. Inorgan ...

with the

chemical formula A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as pare ...

. It is one of several sodium phosphates. The

salt In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...

is known in anhydrous form as well as hydrates , where ''n'' is 2, 7, 8, and 12. All are water-soluble white powders. The anhydrous salt is

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption (chemistry), absorption or adsorption from the surrounding Natural environment, environment, which is usually at normal or room temperature. If water mol ...

. The pH of disodium hydrogen phosphate water solution is between 8.0 and 11.0, meaning it is moderately

basic Basic or BASIC may refer to: Science and technology * BASIC, a computer programming language * Basic (chemistry), having the properties of a base * Basic access authentication, in HTTP Entertainment * Basic (film), ''Basic'' (film), a 2003 film ...

: :

Production and reactions

It can be generated by neutralization of

phosphoric acid Phosphoric acid (orthophosphoric acid, monophosphoric acid or phosphoric(V) acid) is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formula . It is commonly encountered as an 85% aqueous solution, ...

with

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...

: : Industrially It is prepared in a two-step process by treating dicalcium phosphate with sodium bisulfate, which precipitates calcium sulfate:Klaus Schrödter, Gerhard Bettermann, Thomas Staffel, Friedrich Wahl, Thomas Klein, Thomas Hofmann "Phosphoric Acid and Phosphates" in ''Ullmann’s Encyclopedia of Industrial Chemistry'' 2008, Wiley-VCH, Weinheim. : In the second step, the resulting solution of monosodium phosphate is partially neutralized: :

Uses

It is used in conjunction with

trisodium phosphate Trisodium phosphate (TSP) is an inorganic compound with the chemical formula . It is a white, granular or crystalline solid, highly soluble in water, producing an alkaline solution. TSP is used as a cleaning agent, builder, lubricant, food addi ...

in foods and water softening treatment. In foods, it is used to adjust pH. Its presence prevents coagulation in the preparation of condensed milk. Similarly, it is used as an anti-caking additive in powdered products. It is used in desserts and puddings, e.g.

Cream of Wheat Cream of Wheat is an American brand of farina (food), farina, a type of breakfast porridge mix made from wheat middlings. It looks similar to grits, but is smoother in texture since it is made with ground wheat berry, wheat kernels instead of gr ...

to quicken cook time, and Jell-O Instant Pudding for thickening. In water treatment, it retards calcium scale formation. It is also found in some detergents and cleaning agents. Heating solid disodium phosphate gives the useful compound tetrasodium pyrophosphate: :

Laxative

Monobasic and dibasic sodium phosphate are used as a saline laxative to treat

constipation Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The Human feces, stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the ...

or to clean the bowel before a colonoscopy.

References

External links

* solubility in Prophylaxis alcohol {{Phosphates Sodium compounds Phosphates Edible thickening agents